Draft version July 26, 2021 Typeset using LATEX twocolumn style in AASTeX631

Comprehensive Broadband X-ray and Multiwavelength Study of Active Galactic Nuclei in Local 57 Ultra/luminous Observed with NuSTAR and/or Swift/BAT

Satoshi Yamada ,1 Yoshihiro Ueda ,1 Atsushi Tanimoto ,2 Masatoshi Imanishi ,3, 4 Yoshiki Toba ,1, 5 Claudio Ricci ,6, 7, 8 and George C. Privon 9

1Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan 2Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan 3National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588, Japan 4Department of Astronomical Science, Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 5Research Center for Space and Cosmic Evolution, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan 6N´ucleo de Astronom´ıade la Facultad de Ingenier´ıa,Universidad Diego Portales, Av. Ej´ercito Libertador 441, Santiago, Chile 7Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, People’s Republic of China 8George Mason University, Department of Physics & Astronomy, MS 3F3, 4400 University Drive, Fairfax, VA 22030, USA 9National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA

(Received April 13, 2021; Revised June 11, 2021; Accepted Jul, 2021)

ABSTRACT We perform a systematic X-ray spectroscopic analysis of 57 local ultra/luminous infrared systems (containing 84 individual galaxies) observed with Nuclear Spectroscopic Telescope Array and/or Swift/BAT. Combining soft X-ray data obtained with Chandra, XMM-Newton, and/or Swift/XRT, we identify 40 hard (>10 keV) X-ray detected active galactic nuclei (AGNs) and con- strain their torus parameters with the X-ray clumpy torus model XCLUMPY (Tanimoto et al. 2019). Among the AGNs at z < 0.03, for which sample biases are minimized, the fraction of Compton-thick 24 −2 +14 +12 (NH ≥ 10 cm ) AGNs reaches 64−15% (6/9 sources) in late mergers, while 24−10% (3/14 sources) in early mergers, consistent with the tendency reported by Ricci et al.(2017a). We find that the bolomet- ric AGN luminosities derived from the infrared data increase, but the X-ray to bolometric luminosity ratios decrease, with merger stage. The X-ray weak AGNs in late mergers ubiquitously show massive 46 −1 outflows at sub-pc to kpc scales. Among them, the luminous AGNs (Lbol,AGN ∼ 10 erg s ) 23 −2 have relatively small column densities of .10 cm and almost super- ratios (λEdd ∼ 1.0). (22) Their torus covering factors (CT ∼ 0.6) are larger than those of Swift/BAT selected AGNs with similarly high Eddington ratios. These results suggest a scenario that, in the final stage of mergers, multiphase strong outflows are produced due to chaotic quasi-spherical inflows and the AGN becomes extremely X-ray weak and deeply buried due to obscuration by inflowing and/or outflowing material.

Keywords: Black hole physics (159); Active galactic nuclei (16); X-ray active galactic nuclei (2035); arXiv:2107.10855v1 [astro-ph.GA] 22 Jul 2021 Infrared galaxies (790); Supermassive black holes (1663); Observational astronomy (1145)

1. INTRODUCTION nomenon. Many theoretical studies (e.g., Hopkins et al. For understanding the coevolution of galaxy and su- 2006) suggest that major mergers trigger both intense permassive black hole (SMBH), gas-rich galaxy merg- formation in the galaxies and mass accretion onto ers (i.e., major mergers) are considered as a key phe- the SMBHs, being enshrouded by a huge amount of gas and dust. This makes them appear as luminous and ultraluminous infrared galaxies (U/LIRGs; Sanders & Corresponding author: Satoshi Yamada [email protected] 2 Yamada et al.

Mirabel 1996 for a review)1 containing obscured active in the AGN structure between mergers and nonmergers galactic nuclei (AGNs). ULIRGs may be in a prephase of may provide us with a clue. Yamada et al.(2020) apply quasi stellar objects () where star forming activ- the XCLUMPY model to the spectra of two “nonmerg- ities become relatively weak. Thus, studies of ULIRGs ing LIRGs” and find that their AGNs are not buried, are indispensable to reveal the whole history of star for- unlike those in late mergers. This implies that accreting mation and SMBH growth triggered by major mergers. environments are different between major mergers and Recent numerical simulations of galaxy mergers (e.g., secular processes. From a statistical study of Swift/BAT Kawaguchi et al. 2020) predict that the mass accretion selected AGNs, whose majority are nonmergers, Ricci rates can exceed the Eddington limits as the separa- et al.(2017b) suggest that the torus structure is regu- tion of the two SMBHs decreases. However, the nuclear lated by radiation pressure from the AGN. Thus, stud- environments of accreting SMBHs in U/LIRGs have ies of AGNs in U/LIRGs will enable us to answer if the been still veiled in mystery. This is because the cen- same physics works or not in deeply buried AGNs in tral regions in the final phase of mergers become deeply major mergers. “buried” with large covering factors, where even the di- Comparison of X-ray luminosities3 with bolometric rection of the lowest dust column-density can be opaque ones inferred from infrared observations also provide us to the ionizing UV photons (e.g., Imanishi et al. 2006, with information on the AGN physics in U/LIRGs. Teng 2008; Yamada et al. 2019). To shed light on the proper- et al.(2015) report that the bolometric-to-X-ray lumi- ties of these hidden AGNs, hard X-rays (>10 keV) are nosity ratio (κbol,X) of the AGN in an ULIRG is much 2 4 useful thanks to their high penetrating power against ob- larger (i.e., X-ray weak), κbol,X ∼ 10 –10 , than that of 2 scuration. In fact, Ricci et al.(2017a) identity 25 AGNs a normal AGN, for which typically κbol,X ∼ 20 (e.g., Va- in 30 interacting U/LIRGs with the Nuclear Spectro- sudevan & Fabian 2007). The reason for the difference is scopic Telescope Array (NuSTAR; Harrison et al. 2013) not clear. To answer this question, comprehensive mul- and/or Swift/BAT, which cover the 3–79 keV and 14– tiwavelength investigation of a large number of AGNs in 195 keV bands, respectively. They also report that the U/LIRGs is required. fraction of Compton-thick (CT; with hydrogen column In this work, we carry out a systematic X-ray spectral 24 −2 densities NH ≥ 10 cm ) AGNs is significantly larger study of a sample of 57 local U/LIRG systems (con- +12 +13 (65−13%) in late mergers than in early ones (35−12%). taining 84 individual galaxies) observed with NuSTAR This indicates that the AGNs in late stage mergers are and/or Swift/BAT by combining the available soft X- indeed deeply buried by CT material. ray data of Chandra, XMM-Newton, Suzaku, and/or To best constrain the properties of obscuring mate- Swift/XRT. The paper is structured as follows. Sec- rial (“torus”) in AGNs through X-ray observations, con- tion2 describes our sample and merger classification. struction of spectral models based on the realistic ge- Details of the X-ray observations and data reduction ometries of AGN tori is crucial. Since many studies in- are presented in Section3. Section4 describes our X- dicate that the torus structure is clumpy (e.g., Krolik & ray spectral analysis. In Section5 we compare our X-ray Begelman 1988; Wada & Norman 2002; H¨onig& Beckert results with those of previous multiwavelength observa- 2007; Laha et al. 2020), Tanimoto et al.(2019) develop tions. In Section6 we discuss the origin of the X-ray the X-ray clumpy torus model called XCLUMPY, which weakness, torus structure, and the connection between adopts the same geometry as that of the infrared (IR) AGN and starburst activities. Section7 summarizes our CLUMPY model (Nenkova et al. 2008a,b). The model is main conclusions. In two companion papers (Ricci et al. applied to the broadband X-ray spectra of nearby AGNs 2021a; C. Ricci et al., in preparation) we will discuss: i) to constrain their torus covering factors (e.g., Miyaji the evolution of obscuration along the merger sequence, et al. 2019; Tanimoto et al. 2020, 2021; Toba et al. 2020; and ii) the relation between X-ray emission and multi- Ogawa et al. 2021; Uematsu et al. 2021). wavelength proxies of AGN activity. The cosmological −1 −1 To understand the connection between mass accretion parameters adopted are H0 = 70 km s Mpc ,ΩM = and obscuration in mergers, investigation of differences

3 In this paper, we define “absorption-corrected X-ray luminosi- 1 LIRGs and ULIRGs are defined by using the total 8–1000 µm ties” of an AGN in the 2–10 keV and 10–50 keV bands, L2−10 11 12 12 and L10−50, as those corrected for line-of-sight absorption that luminosities of LIR = 10 –10 L and >10 L , respectively. is recognized in the X-ray spectra. It remains possible, how- 2 Considering the relation between V -band extinction and hydro- ever, that a part of the X-ray emission from the innermost region gen column density of the Galactic interstellar medium, N /A H V is completely blocked by optically thick material and hence the = 2 × 1021 cm−2 mag−1 (Draine 2003), the penetration depth of true X-ray luminosity could be underestimated, as discussed in 10 keV X-rays corresponds to at least A ∼ 500 mag. V Section 6.1.6. 3

0.3, and ΩΛ = 0.7. All uncertainties are quoted at the it is reported that they show different properties of star 90% confidence level unless otherwise stated. formation and AGN obscuration from those of stage- D mergers (e.g., Shangguan et al. 2019; Yamada et al. 2. SAMPLE DESCRIPTION 2019). Thus, we treat these objects as stage-N in this 2.1. Sample Selection work. Moreover, we re-categorize the merger stages for the seven systems by the following reasons: The IRAS Revised Bright Galaxy Sample (RBGS; Sanders et al. 2003) is an all-sky survey of IR galax- 1. NGC 1068: the galaxy is a LIRG in the GOALS ies having the IRAS 60 µm flux densities above 5.24 Jy sample but is not classified by Stierwalt et al. and Galactic latitude |b| ≥ 5◦. Our targets are taken (2013). Although NGC 1068 may show tidally in- from the GOALS sample (Armus et al. 2009), which is duced structures of a past minor merger (Tanaka a complete subset of the RBGS with an 8–1000 µm lu- et al. 2017), the host galaxy is morphologically 11 minosity threshold of LIR ≥ 10 L consisting of 180 similar to a normal . As the case of LIRGs and 22 ULIRGs at z < 0.088. NGC 7130, we treat it as a stage-N source. Most of the U/LIRGs in GOALS are interacting sys- 2. ESO 203-1: the system is assigned as a stage-D tems (Haan et al. 2011; Stierwalt et al. 2013). In to- merger by Stierwalt et al.(2013). The HST im- tal 244 and 246 nuclei are observed with the Spitzer ages show, however, that it is an early merger with SH and LH IRS modules, respectively, within the 202 two nuclei separated by ∼8 kpc (Haan et al. 2011; U/LIRG systems (Inami et al. 2013). In X-rays, the Ricci et al. 2021a). We thus regard it as a stage-B presence of AGNs in the individual nuclei is investi- merger. gated with Chandra for 106 systems (C-GOALS; Iwa- sawa et al. 2011a; Torres-Alb`a et al. 2018). Ricci 3. NGC 4418 and MCG+00-32-013: the brighter et al.(2017a) report the nuclear AGN/starburst ac- galaxy, NGC 4418, is classified as a stage-N LIRG, tivities of 30 interacting systems in GOALS, basically but recent works (Varenius et al. 2017; Boettcher using NuSTAR observations. In this work, we select et al. 2020) suggest that the central starburst ac- all 57 U/LIRG systems (containing 84 galaxies) in the tivity would be enhanced by the nearby dwarf GOALS sample observed with NuSTAR by 2020 April galaxy MCG+00-32-013 with the separation of and/or detected with Swift/BAT in the 105-month data. 29.4 kpc. Since no clear feature of galactic interac- NGC 232/NGC 235 is the only system that is detected tion is evident, we classify it as a stage-A merger. with Swift/BAT but not has been observed with NuS- 4. MCG–03-34-064: the source is classified as a TAR. Our sample consists of 46 merging and 11 non- stage-A merger consisting of MCG–03-34-064 and merging U/LIRG systems. its nearby galaxy MCG–03-34-063, whose angular 00 2.2. Merger Stages separation is 106. 2. However, they have different redshifts, 0.0165 and 0.0213, respectively. Alonso- We adopt the visually derived merger stage classifica- Herrero et al.(2012) also report this point. Thus, tion of Stierwalt et al.(2013), which is mainly based on we re-classify the brighter IR source MCG–03-34- the Hubble (HST) and Spitzer/IRAC 064 as a stage-N object. 3.6 µm images. According to their results and re- cent works (e.g., Ricci et al. 2017a), we divide the 5. IC 4518A and IC 4518B: the system is a LIRG in morphologies into five designations: “stage-A” (galaxy the GOALS sample, but is not classified by Stier- pairs prior to a first encounter); “stage-B” (post-first- walt et al.(2013). We treat it as a stage-B merger encounter with galaxy disks still symmetric and in tact according to Ricci et al.(2017a), who report signs but with signs of tidal tails); “stage-C” (showing amor- of tidal interactions and the separation of ∼12 kpc phous disks, tidal tails, and other signs of merger activ- in the optical and IR images. ity); “stage-D” (two nuclei in a common envelop); and 6. IRAS F18293–3413: the galaxy is assigned as a “stage-N” (no signs of merger activity or massive neigh- stage-C merger by Stierwalt et al.(2013). As bors). Hereafter, stage-A and B galaxies are assigned as noted by Ricci et al.(2017a), however, the HST “early mergers”, stage-C and D sources are “late merg- imaging shows that the two sources do not share ers”, and stage-N objects are “nonmergers”. a common envelop, and the object seems to be There remain possibilities that some stage-N sources, in a past merger (Haan et al. 2011). Considering such as NGC 7130 (Davies et al. 2014), are past mergers. the much smaller size of the companion source, we In general, however, it is very difficult to distinguish re-categorized it as a stage-N object. whether a stage-N source is a past merger or not. Also, 4 Yamada et al.

Table 1. Basic Information of our Sample

IRAS Name Object Name R.A. Decl. z M D12 D12 log(LIR) IRS

(J2000) (J2000) (arcsec) (kpc) (L ) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

F00085–1223 NGC 34 00:11:06.61 −12:06:28.33 0.0196 D S S 11.49 Y F00163–1039 N MCG–02-01-052 00:18:50.15 −10:21:41.49 0.0273 B 56.1 30.7 [11.48] n F00163–1039 S MCG–02-01-051 00:18:50.90 −10:22:36.49 0.0271 B 56.1 30.7 11.48 Y F00344–3349 ESO 350-38 00:36:52.49 −33:33:17.23 0.0206 C 5.2g 2.2g 11.28 Y F00402–2349 W NGC 232 00:42:45.81 −23:33:40.69 0.0226 B 120.8 54.7 [11.44]: Y F00402–2349 E NGC 235 00:42:52.81 −23:32:27.71 0.0222 B 120.8 54.7 [11.44]: Y F00506+7248 E MCG+12-02-001 00:54:03.94 +73:05:05.23 0.0157 C 0.9h 0.3h 11.50 Y F01053–1746 W IC 1623A 01:07:46.49 −17:30:22.50a 0.0201 C 15.7 6.4 [11.71] n F01053–1746 E IC 1623B 01:07:47.57 −17:30:25.04 0.0203 C 15.7 6.4 11.71 Y F02071–1023 W2 NGC 833 02:09:20.85 −10:07:59.11 0.0129 A 56.4 15.3 [11.05]: Y F02071–1023 W NGC 835 02:09:24.61 −10:08:09.31 0.0136 A 56.4 15.3 [11.05]: Y F02071–1023 E NGC 838 02:09:38.56 −10:08:46.12 0.0128 A 148.8 39.1 [11.05]: Y F02071–1023 S NGC 839 02:09:42.73 −10:11:01.64 0.0129 A 148.8 39.1 [11.05]: Y F02401–0013 NGC 1068 02:42:40.77 −00:00:47.84 0.0038† N n n 11.40 Y F03117+4151 N UGC 2608 03:15:01.41 +42:02:08.39 0.0233 N n n 11.41 Y F03117+4151 S UGC 2612 03:15:14.60 +41:58:50.51 0.0318 N n n [11.41] Y F03164+4119 NGC 1275 03:19:48.16 +41:30:42.11 0.0176 N n n 11.26 Y F03316–3618 NGC 1365 03:33:36.46 −36:08:26.37 0.0055† N n n 11.00 Y F04454–4838 ESO 203-1 04:46:49.54 −48:33:29.90a 0.0529 B 7.5a 7.7a 11.86 Y F05054+1718 W CGCG 468-002W 05:08:19.71 +17:21:48.09 0.0175 B 29.5 10.3 [11.22]: Y F05054+1718 E CGCG 468-002E 05:08:21.21 +17:22:08.34 0.0168 B 29.5 10.3 [11.22]: Y F05189–2524 IRAS F05189–2524 05:21:01.40 −25:21:45.27 0.0426 D S S 12.16 Y F06076–2139 N IRAS F06076–2139 06:09:45.79 −21:40:23.52 0.0374 C 8.3 6.2 11.65 Y F06076–2139 S 2MASS 06094601–2140312 06:09:46.01 −21:40:31.26 0.0374 C 8.3 6.2 [11.65] n F08354+2555 NGC 2623 08:38:24.02 +25:45:16.29 0.0185 D S S 11.60 Y F08520–6850 W ESO 060-IG016 West 08:52:29.36 −69:02:01.07 0.0451 B 15.4 13.6 [11.82] n F08520–6850 E ESO 060-IG016 East 08:52:32.05 −69:01:55.74 0.0451 B 15.4 13.6 11.82 Y F08572+3915 IRAS F08572+3915 09:00:25.36 +39:03:54.23 0.0580 D 4.4h 5.6h 12.16 Y F09320+6134 UGC 5101 09:35:51.69 +61:21:10.52 0.0394 D S S 12.01 Y F09333+4841 W MCG+08-18-012 09:36:30.86 +48:28:10.46 0.0252 A 65.3 33.6 [11.34] n F09333+4841 E MCG+08-18-013 09:36:37.19 +48:28:27.86 0.0259 A 65.3 33.6 11.34 Y F10015–0614 S MCG–01-26-013 10:03:57.03 −06:29:47.12 0.0161 A 108.8 36.5 [11.37] n F10015–0614 N NGC 3110 10:04:02.12 −06:28:29.12 0.0169 A 108.8 36.5 11.37 Y F10038–3338 ESO 374-IG032 10:06:04.58 −33:53:05.55 0.0340 D S S 11.78 Y F10257–4339 NGC 3256 10:27:51.28 −43:54:13.55 0.0094 D 5.1h 1.0h 11.64 Y F10565+2448 IRAS F10565+2448 10:59:18.13 +24:32:34.74 0.0431 D 7.4h 6.7h 12.08 Y F11257+5850 W NGC 3690 West 11:28:31.00 +58:33:41.20b 0.0102 C 22.0 4.6 [11.93]: Y F11257+5850 E NGC 3690 East 11:28:33.70 +58:33:47.20b 0.0104 C 22.0 4.6 [11.93]: Y F12043–3140 N ESO 440-58 12:06:51.80 −31:56:47.00 0.0232 B 11.8 5.5 [11.43]: Y F12043–3140 S MCG–05-29-017 12:06:51.87 −31:56:58.75 0.0228 B 11.8 5.5 [11.43]: Y F12112+0305 IRAS F12112+0305 12:13:46.11 +02:48:41.50 0.0733 D 3.0i 4.1i 12.36 Y F12243–0036 NW NGC 4418 12:26:54.63 −00:52:39.51 0.0073† A 179.9 29.4 11.19 Y

Table 1 continued 5 Table 1 (continued)

IRAS Name Object Name R.A. Decl. z M D12 D12 log(LIR) IRS

(J2000) (J2000) (arcsec) (kpc) (L ) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

F12243–0036 SE MCG+00-32-013 12:27:04.53 −00:54:21.14 0.0074† A 179.9 29.4 [11.19] n F12540+5708 Mrk 231 12:56:14.23 +56:52:25.24 0.0422 D S S 12.57 Y F12590+2934 S NGC 4922S 13:01:24.51 +29:18:30.15 0.0239 C 22.1 10.6 [11.38] n F12590+2934 N NGC 4922N 13:01:25.27 +29:18:49.88 0.0236 C 22.1 10.6 11.38 Y F13126+2453 IC 860 13:15:03.51 +24:37:07.80 0.0112 N n n 11.14 Y 13120–5453 IRAS 13120–5453 13:15:06.38 −55:09:22.60 0.0308 D S S 12.32 Y F13188+0036 NGC 5104 13:21:23.12 +00:20:33.38 0.0186 N n n 11.27 Y F13197–1627 MCG–03-34-064 13:22:24.48 −16:43:42.09 0.0165 N n n 11.28 Y F13229–2934 NGC 5135 13:25:44.06 −29:50:01.24 0.0137 N n n 11.30 Y F13362+4831 S Mrk 266B 13:38:17.35 +48:16:31.90 0.0276 B 10.1 5.6 [11.56]: Y F13362+4831 N Mrk 266A 13:38:17.78 +48:16:41.02 0.0279 B 10.1 5.6 [11.56]: Y F13428+5608 Mrk 273 13:44:42.07 +55:53:13.17 0.0378 D 0.9h 0.7h 12.21 Y F14348–1447 IRAS F14348–1447 14:37:38.32 −15:00:23.97 0.0827 D 3.4j 5.2j 12.39 Y F14378–3651 IRAS F14378–3651 14:40:59.01 −37:04:31.94 0.0681 D S S 12.23 Y F14544–4255 W IC 4518A 14:57:41.18 −43:07:55.49c 0.0163 B 35.5 11.5 11.23 Y F14544–4255 E IC 4518B 14:57:44.41 −43:07:52.69 0.0155 B 35.5 11.5 [11.23] n F15250+3608 IRAS F15250+3608 15:26:59.43 +35:58:37.23 0.0552 D 0.7k 0.8 12.08 Y F15327+2340 W Arp 220W 15:34:57.22 +23:30:11.49d 0.0181 D 1.0 0.4 [12.28]: Y(u) F15327+2340 E Arp 220E 15:34:57.29 +23:30:11.34d 0.0181 D 1.0 0.4 [12.28]: Y(u) F16504+0228 S NGC 6240S 16:52:58.90 +02:24:03.36e 0.0245 D 1.7 0.8 [11.93]: Y(u) F16504+0228 N NGC 6240N 16:52:58.92 +02:24:05.03e 0.0245 D 1.7 0.8 [11.93]: Y(u) F16577+5900 N NGC 6285 16:58:24.02 +58:57:21.23 0.0190 B 91.0 34.5 [11.37] Y F16577+5900 S NGC 6286 16:58:31.38 +58:56:10.21 0.0183 B 91.0 34.5 11.37 Y F17138–1017 IRAS F17138–1017 17:16:35.70 −10:20:38.00 0.0173 D S S 11.49 Y F18293–3413 IRAS F18293–3413 18:32:41.18 −34:11:27.46 0.0182 N S S 11.88 Y F19297–0406 IRAS F19297–0406 19:32:22.30 −04:00:01.79 0.0857 D S S 12.45 Y F20221–2458 SW NGC 6907 20:25:06.94 −24:48:38.16 0.0106 B 43.9 9.4 11.11 Y F20221–2458 NE NGC 6908 20:25:08.97 −24:48:04.11f 0.0102 B 43.9 9.4 [11.11] n 20264+2533 W NGC 6921 20:28:28.84 +25:43:24.19 0.0145 A 91.4 26.5 [11.11] n 20264+2533 E MCG+04-48-002 20:28:35.06 +25:44:00.18 0.0139 A 91.4 26.5 11.11 Y F20550+1655 NW II Zw 096 20:57:23.63 +17:07:44.60 0.0355 C 11.6 8.1 [11.94]: Y F20550+1655 SE IRAS F20550+1655 SE 20:57:24.08 +17:07:34.96 0.0350 C 11.6 8.1 [11.94]: Y F20551–4250 ESO 286-19 20:58:26.82 −42:38:59.42 0.0430 D S S 12.06 Y F21453–3511 NGC 7130 21:48:19.49 −34:57:04.73 0.0162 N n n 11.42 Y F23007+0836 S NGC 7469 23:03:15.67 +08:52:25.28 0.0163 A 79.7 26.2 11.65 Y F23007+0836 N IC 5283 23:03:18.00 +08:53:37.13 0.0160 A 79.7 26.2 [11.65] n F23128–5919 ESO 148-2 23:15:46.77 −59:03:15.94 0.0446 C 4.5l 3.9 12.06 Y F23157+0618 NGC 7591 23:18:16.27 +06:35:09.11 0.0165 N n n 11.12 Y F23254+0830 W NGC 7674 23:27:56.70 +08:46:44.24 0.0289 A 33.3 19.5 11.56 Y F23254+0830 E MCG+01-59-081 23:27:58.75 +08:46:57.88 0.0295 A 33.3 19.5 [11.56] n

Table 1 continued 6 Yamada et al. Table 1 (continued)

IRAS Name Object Name R.A. Decl. z M D12 D12 log(LIR) IRS

(J2000) (J2000) (arcsec) (kpc) (L ) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

23262+0314 W NGC 7679 23:28:46.67 +03:30:40.99 0.0171 A 269.8 93.8 11.11 Y 23262+0314 E NGC 7682 23:29:03.90 +03:32:00.00 0.0171 A 269.8 93.8 [11.11] n

Note—Columns: (1) IRAS name; (2) object name; (3–4) the best available source right ascension and declination (J2000) in CDS Portal (based on SIMBAD; http://cdsportal.u-strasbg.fr/); (5) in NASA/IPAC Extragalactic Database (NED); (6) merger stage as classified from the (HST) and IRAC 3.6 µm imaging (Stierwalt et al. 2013); (7–8) the separation between the two nuclei in arcsec and kpc. S and n mean that a single nucleus is observed in merging and nonmerging U/LIRGs, respectively; (9) logarithmic total IR luminosity in units of L (Armus et al. 2009). Values in brackets should be upper limits due to contamination from nearby much brighter (or equally bright with the suffix “:”) IR sources. (10) Y and n mark detection and nondetection with Spitzer/IRS in the 10–20 µm (SH) or 19–38 µm (LH) band, respectively (Alonso-Herrero et al. 2012; Mazzarella et al. 2012; Inami et al. 2013). The (u) means that the two nuclei are not clearly divided. References: The source positions in Column (3–4) and the separations in Column (7–8) are adopted from the references: (a) Haan et al. (2011); (b) Zezas et al.(2003); (c) Alonso-Herrero et al.(2020); (d) Scoville et al.(2017); (e) Puccetti et al.(2016); (f) NED; (g) Kunth et al.(2003); (h) Ricci et al.(2017a); (i) Imanishi et al.(2020); (j) Imanishi & Saito(2014); (k) Scoville et al.(2000); (l) Zenner & Lenzen (1993).

† We utilize redshift-independent measurements of the distance for the closest objects (at z < 0.01), NGC 1068 (14.4 Mpc; Tully 1988; Bauer et al. 2015), NGC 1365 (17.3 Mpc; Venturi et al. 2018), and NGC 4418/MCG+00-32-013 (34 Mpc; e.g., Ohyama et al. 2019).

to confirm the presence of AGN(s) in each system as reported in AppendixB. 7 NGC 6907 and NGC 6908: NGC 6907 is classified 2.4. Characteristics of Our Sample as stage-N but Madore et al.(2007) suggest that Figure1 shows the histograms of the 8–1000 µm IR lu- NGC 6907 and the dwarf galaxy NGC 6908 are minosity, redshift, and merger stage for the U/LIRGs in interacting and show tidal signatures. The sep- the GOALS, C-GOALS, and our samples. As seen from aration is 9.4 kpc. Thus, we treated them as a the upper and middle panels, our sample covers the full stage-B merger. 11.0 ranges of the parent GOALS sample over LIR = 10 – 12.6 2.3. Basic Information on Individual Objects 10 L and z = 0.001–0.088. A Kolmogorov-Smirnov (KS) test indicates that the difference in the IR lumi- To obtain the accurate galaxy separations in mergers, nosity distribution between our targets and the rest of we refer to the central positions not only from the SIM- the GOALS sample is significant at a >99% confidence BAD but also from the literature. We finally confirm level, while the difference in the redshift is not (p-value = them via visual inspection in the optical images (ob- 0.214). Thus, we may regard our sample as a good rep- served with HST, PanSTARRS, SDSS, and/or DSS2), resentative subsample of the local U/LIRGs, although it the mid-IR images (with Spitzer/IRAC 1–4), and/or is weakly biased toward higher IR luminosities compared the soft X-ray images (with Chandra and/or XMM- with the parent GOALS sample. Newton). The basic properties of our targets and their As shown in the bottom panel, the numbers of the five references are summarized in Table1. merger stages in our sample are 8, 10, 8, 20, and 11 for In this work, we utilize the hard X-ray observations stage-A, B, C, D, and N, whereas those in GOALS are with NuSTAR to identify the AGNs in local U/LIRGs. 36, 34, 20, 53, and 59, respectively.4 A chi-square test of To determine which galaxy in the system contains an independence suggests that the difference of the distri- AGN, we firstly check the peak position in the NuS- bution between our targets and the rest of the GOALS TAR 8–24 keV image against the galaxy positions (see sample is not significant (p-value = 0.132). We note a Section 4.1). In many cases, however, NuSTAR can- possible bias that objects that show AGN features in the not resolve the merging systems because their angular soft X-ray and/or IR band may have been preferentially separations are smaller than the angular resolution (a selected to be observed with NuSTAR. The smaller frac- 00 full-width at half-maximum (FWHM) of 18 and a half tion of stage-N (nonmergers) in our sample than in the power diameter of 5800). In such cases, it is also possible that a system actually contain more than one AGNs. Thus, we also refer to the soft X-ray (i.e., Chandra 4 We treat ESO 550-25 as a stage-B merger based on the optical and/or XMM-Newton) and other multiwavelength data image, which is not classified by Stierwalt et al.(2013). 7

GOALS sample may be affected by this bias. We have to keep it mind when we discuss any statistical proper- 50 GOALS (202) ties (e.g., AGN fraction) of U/LIRGs using our sample C-GOALS (106) (see e.g., Section 5.2). This work (57) 40 2.5. Targets with Complex Spectral Features For the eight well-studied U/LIRG systems (hosting 30 10 AGNs), NGC 1068, NGC 1275, NGC 1365, Mrk 266, NGC 6240, UGC 2608, NGC 5135, and NGC 20 7469, we refer to the X-ray spectral results of previ- ous works based on the NuSTAR data. The broad- Number of sources 10 band spectra of NGC 1068, NGC 1275, and NGC 1365 are reproduced with a multi-component reflector model (Bauer et al. 2015), a jet-dominant AGN model (Rani 0 5 11.0 11.2 11.4 11.6 11.8 12.0 12.2 12.4 12.6 et al. 2018) , and a multi-layer variable absorber model log(LIR/L ) (Rivers et al. 2015), respectively. The dual AGN sys- tems of Mrk 266B/Mrk 266A (Iwasawa et al. 2020) and NGC 6240S/NGC 6240N (Puccetti et al. 2016) are ob- GOALS (202) served with Chandra by separating the individual AGN 80 C-GOALS (106) components, and their hard X-ray emissions are de- 70 This work (57) tected with NuSTAR. The absorption hydrogen column

60 densities of these five U/LIRG systems taken from the literature are summarized in Table2. 6 We also refer to 50 the NuSTAR results of UGC 2608, NGC 5135 (heavily 40 CT AGNs in stage-N LIRGs; Yamada et al. 2020), and NGC 7469 (unobscured AGN whose spectrum is sub- 30 ject to ionized warm absorbers; Ogawa et al. 2021), for

Number of sources 20 which the XCLUMPY torus model is applied; the best- fitting results are shown in Table5. In AppendixB, 10 we present detailed information obtained from previous 0 0.00 0.02 0.04 0.06 0.08 X-ray and multiwavelength studies for all 84 galaxies Redshift (z) including these 8 U/LIRG systems.

60 GOALS (202) 3. OBSERVATIONS AND DATA REDUCTION C-GOALS (106) 50 This work (57) For the 49 U/LIRG systems other than the 8 sys- tems mentioned in Section 2.5, we analyzed all the 40 available data of NuSTAR (Section 3.1), Chandra (Sec- tion 3.2), XMM-Newton (Section 3.3), and Suzaku (Sec- 30 tion 3.4), observed by 2020 April. We also analyzed their Swift/XRT data when no other soft X-ray data 20

Number of sources 5 NGC 1275 is a radio galaxy in the Perseus cluster hosting a low- 10 luminosity AGN ( Collaboration et al. 2018). The con- tamination of the jet emission makes it difficult to constrain the 0 nuclear structure. Thus, we only discuss its X-ray flux and band A B C D N ratio in this paper. Merger stage 6 The hydrogen column densities of NGC 1068, NGC 1365, Mrk 266B/Mrk 266A and NGC 6240S/NGC 6240N are derived Figure 1. Upper panel: histogram of IR luminosity (LIR) with other torus models than XCLUMPY. We note that the col- for the whole GOALS sample (gray) compared with the C- umn densities obtained with XCLUMPY are consistent with the GOALS sample (blue) and our sample (red). Middle panel: values obtained with smooth-torus models for the other AGNs in histogram of redshift (taken from NED). Bottom panel: his- our sample (see also AppendixB). togram of merger stage. 8 Yamada et al.

Table 2. Previous NuSTAR Works for AGNs with Complex Spectral Features

LoS Object NH Model Ref. (1) (2) (3) (4)

NGC 1068 ∼1000 Multi-component reflector model Bauer et al.(2015) NGC 1275 ··· Jet-dominant AGN model in the Perseus Cluster Rani et al.(2018) NGC 1365 ∼10 Multi-layer variable absorber model Rivers et al.(2015) Mrk 266B/Mrk 266A 700/6.8 Dual-AGN model Iwasawa et al.(2020) +21 +72 NGC 6240S/NGC 6240N 147−17/155−23 Dual-AGN model Puccetti et al.(2016) Note—Columns: (1) object name; (2) line-of-sight hydrogen column density in units of 1022 cm−2; (3–4) X-ray spectral model and their references.

were available, and utilized the Swift/BAT spectra in nearby sources and CCD gaps. Net exposure times for the 105 month catalog if detected (Section 3.5). For the these targets range from ∼10 ks to ∼200 ks. After con- other 8 systems, we reduced the same data as used in firming that the spectra of the two plane mod- their references (see Section 2.5) and obtained the count ules (FPMA and FPMB; FPM) agreed with each other rates, in order to treat the results in a uniform manner within the statistical uncertainties, we coadded them for all the 57 systems. A log of the X-ray observations with the addascaspec task. of our sample is provided in Table3. In the following, 3.2. Chandra we describe the data reduction for each satellite. We analyzed the Chandra/ACIS (Garmire et al. 2003) 3.1. NuSTAR imaging data of 46 U/LIRG systems, most of which were NuSTAR (Harrison et al. 2013), the first satellite ca- obtained by the project to follow up GOALS objects pable of focusing hard X-rays of 3–79 keV, observed 56 (PI: D. Sanders, see Iwasawa et al. 2011a and Torres- U/LIRG systems in the GOALS sample by Cycle-4. Ten Alb`aet al. 2018). The data reduction was performed systems were observed in Cycle-1 (PI: F.E. Bauer) and with the Chandra data analysis package ciao v4.11 and other 14 systems are in Cycle-3 (PIs: C. Ricci; G. C. the Calibration database (CALDB) v4.8.4.1. The event Privon) as campaigns of observing local U/LIRGs in files were reprocessed with the chandra repro tool. different merger stages. We analyzed all these data in- The source spectrum was extracted from the circular 00 cluding those of the other 32 systems in the archive. region of a typically 10 radius centered on the optical We reduced the data using the NuSTAR Data position or the X-ray peak position for a bright source. Analysis Software (nustardas) v1.8.0 within HEA- We adopt a radius large enough to include the extended 00 SOFT v6.25, adopting the calibration files released emission of the whole galaxy, between 3 (for a galaxy 00 on 2019 May 13. Calibrated and cleaned event files in a close merging system, ESO 440-58) and 50 (for the were produced using the nupipeline script with the nearest source, NGC 1068). The background spectrum saamode=optimized and tentacle=yes options. was taken from a nearby source-free circular region with 00 00 The nuproducts task was used to extract the source the same, or 10 radius when the source radius is <10 . spectra, background spectra, and response files. We 3.3. XMM-Newton adopted circular source regions of 4500 radii or those of 3000 or smaller radii7 when there are contaminating The XMM-Newton (Jansen et al. 2001) data of 35 nearby sources close to the target. We also chose 3000 U/LIRG systems were utilized in this work. We re- radii when the signal-to-noise (S/N) ratios of the 8– duced the EPIC/MOS (MOS1, MOS2) and EPIC/pn 24 keV count rates obtained from the 4500 radius re- data with the standard Science Analysis System (sas) gions were lower than <3σ. The background spectra v17.0.0 (Gabriel et al. 2004), and then processed their were taken from the annuluses centered on the X-ray raw data files by the emproc and epproc scripts, re- sources with inner and outer radii of 9000 and 15000, re- spectively. We filtered out periods of high background spectively, by avoiding regions of contamination from activity. The threshold is set to be 1.5 times the aver- aged count rates obtained from periods with ≤0.5 counts s−1 in the energy range above 10 keV. The source spec- 7 We adopted circular regions of 2500 radii for MCG–02-01-052, trum was extracted from a circular region with a radius NGC 833, and IRAS F14348–1447. of typically 2500, whereas the background was from a 9 source-free circular region with a radius of 4000 in the radii of 9000 and 15000, respectively. All spectra of each same CCD chips. We generated the ARF with arfgen object were combined to improve the photon statistics. and RMF with rmfgen. The spectra and response files To better constrain the broadband spectra, we also of EPIC/MOS1 and MOS2 were combined. utilized the time-averaged Swift/BAT spectra in the 105-month catalog (Oh et al. 2018)9, which cover the 3.4. Suzaku 14–195 keV band. To identify the counterparts, we For 18 U/LIRG systems, we utilized the data of the matched our targets with the Swift/BAT catalog within Suzaku (Mitsuda et al. 2007) observations. Suzaku car- error radii defined as: ried the X-ray CCD cameras called the X-ray Imag- s  30.5 2 ing Spectrometers (XIS), covering the 0.2–12 keV band. Error radius (arcmin) = + 0.12, (1) XIS-0, XIS-2, and XIS-3 are frontside-illuminated cam- S/N eras (XIS-FI) and XIS-1 is a backside-illuminated one where S/N represents the significance level of of the (XIS-BI). XIS-2 data were not available after 2006 BAT detection (see Oh et al. 2018). Thus, we adopted November due to the malfunction. We generated the the BAT spectra for 11 galaxies (NGC 235, CGCG cleaned event files with the Suzaku calibration database 468–002W, IRAS F05189–2524, UGC 5101, MCG–03- released on 2018 October 23. The source spectrum was 34-064, Mrk 273, IC 4518A, MCG+04-48-002, NGC selected from a circular region of 1.07 radius, while the 7130, NGC 7674, and NGC 7679) except for the dual background was from a partial annulus with inner and AGN system NGC 833/NGC 835 and 5 systems for outer radii of 3.00 and 5.07 within the field of view by ex- which we refer to the previous NuSTAR results (NGC cluding regions of nearby sources. The ARFs and RMFs 1068, NGC 1275, NGC 1365, NGC 6240S/NGC 6240N, were generated using xisarfgen and xisrmfgen tasks and NGC 7469; see Section 2.5). (Ishisaki et al. 2007), respectively. The spectra and re- sponses of the XIS-FI detectors were merged. Suzaku also carried the Hard X-ray Detector (HXD), 4. X-RAY SPECTRAL ANALYSIS a non-imaging instrument consisting of the silicon PIN diodes (covering 10–70 keV) and GSO scintillators (40– 4.1. X-ray Counts and NuSTAR Counterparts 600 keV). We did not use the GSO data, because our Since many of the U/LIRGs in our sample are inter- targets were too faint to be detected with GSO. The acting systems, we have to identify which of the two HXD-PIN data were reduced with aepipeline task. We galaxies or both contributes to the hard X-ray emission utilized the “tuned” background event files (Fukazawa observed with NuSTAR. First, we check the source peak et al. 2009) to produce the non X-ray background spec- position in the NuSTAR 8–24 keV band image, where tra of HXD-PIN, to which the simulated cosmic X-ray the AGN component is expected to dominate. If the background spectrum was added. NuSTAR position is consistent with one galaxy but not with the other, then we regard the former as the counter- 3.5. Swift part of the hard X-ray source. Here we take into account 00 We analyzed Swift/XRT data covering the ∼0.3– both the statistical (<17 ; i.e., the value of the radius 00 10 keV band for three U/LIRG systems that with 1σ enclosed fraction of ≈51 divided by the S/N ra- 00 were neither observed with Chandra, XMM-Newton, tio) and systematic (8 ; 90% confidence) errors in the as- nor Suzaku: CGCG 468-002W/CGCG 468-002E, trometry of NuSTAR (Harrison et al. 2013). If the NuS- NGC 5104, and NGC 6907/NGC 6908.8 We also ana- TAR error circle contains both galaxies, then we refer to lyzed those of ESO 148-2 and NGC 7679, which showed the previous work based on Chandra and/or other wave- large time variability between the of NuSTAR and length data to identify AGNs in either or both galaxies Chandra/XMM-Newton observations (see AppendixB). (AppendixB). We regard the galaxy that contains an The data reduction was carried out with the xrt- AGN as the counterpart of the NuSTAR source. Among pipeline v0.13.4 script. The source spectrum was taken our sample, only two systems, Mrk 266B/Mrk 266A and from a circular region with a radius of 4500, and the back- NGC 6240S/NGC 6240N, are identified as “dual-AGNs” ground was from a partial annulus with inner and outer where both nuclei significantly contribute to the hard X- ray emission observed with NuSTAR.

8 The Swift/XRT data of ObsID 33513001 and 33513002 performed on 2014 November 3 as ToO observations were not used since they may be largely affected by the emission from the in NGC 6908 (Margutti et al. 2014). 9 https://swift.gsfc.nasa.gov/results/bs105mon/ 10 Yamada et al.

Table 3. X-ray Observation Log

Object Satellite ObsID Observation Date Net Exp. (1) (2) (3) (4) (5)

NGC 34 NuSTAR 60101068002 2015-07-31 21.0/21.0 Chandra 15061 2015-07-31 14.8 XMM-Newton 0150480501 2002-12-22 21.8/21.8/14.5 MCG–02-01-052/MCG–02-01-051 NuSTAR 60101069002 2015-10-29 20.3/20.5 Chandra 13823 2011-10-30 29.6 ESO 350-38 NuSTAR 60374008002 2018-01-15 22.4/22.4 Chandra 8175 2006-10-28 (u; time-v) Chandra 16695 2015-11-29 24.7 Chandra 16696 2016-09-12 24.7 Chandra 16697 2017-11-24 23.8 NGC 232/NGC 235 Chandra 12872 2011-01-17 6.9 Chandra 15066 2013-01-04 14.8 Suzaku 708026010 2013-12-10 19.8/17.2 MCG+12-02-001 NuSTAR 60101070002 2015-08-03 25.8/25.5 Chandra 15062 2012-11-22 14.3 IC 1623A/IC 1623B NuSTAR 50401001002 2019-01-19 197.9/198.8 NuSTAR 60374003002 2018-01-29 20.9/21.0 Chandra 7063 2005-10-20 59.4 XMM-Newton 0025540101 2001-06-26 11.4/11.4/2.7 XMM-Newton 0830440101 2019-01-10 31.2/31.2/25.8 NGC 833/NGC 835/NGC 838/NGC 839 NuSTAR 60061346002 2015-09-13 18.1/18.1 Chandra 15181 2013-07-16 49.5 Chandra 15666 2013-07-18 29.7 Chandra 15667 2013-07-21 58.3 Chandra 923 2000-11-16 (u; time-v) Chandra 10394 2008-11-23 (u; time-v) XMM-Newton 0115810301 2000-01-23 52.3/47.8/44.7 Suzaku 709009010 2014-08-04 (u; cont) NGC 1068 NuSTAR 60002030002 2012-12-18 57.9/57.8 NuSTAR 60002030004 2012-12-20 48.6/48.5 NuSTAR 60002030006 2012-12-21 19.5/19.4 XMM-Newton 0111200101 2000-07-29 39.1/–/35.1 XMM-Newton 0111200201 2000-07-30 39.0/–/35.3 UGC 2608 NuSTAR 60001161002 2014-10-08 22.1/22.2 XMM-Newton 0002942401 2002-01-28 4.8/4.8/2.1 UGC 2612 NuSTAR 60001161002 2014-10-08 22.1/22.2 Chandra 17280 2015-12-11 4.7 XMM-Newton 0002942401 2002-01-28 (u; faint) XMM-Newton 0002942501 2002-01-28 (u; faint) Suzaku 701007010 2006-08-02 (u; faint) Suzaku 701007020 2007-02-04 (u; cont) NGC 1275 NuSTAR 90202046002 2017-02-01 20.3/19.5 NuSTAR 90202046004 2017-02-04 28.2/28.1

Table 3 continued 11 Table 3 (continued)

Object Satellite ObsID Observation Date Net Exp. (1) (2) (3) (4) (5)

XMM-Newton 0085110101 2001-01-30 53.1/53.1/24.6 XMM-Newton 0305780101 2006-01-29 123.3/123.3/76.1 NGC 1365 NuSTAR 60002046002 2012-07-25 36.2/36.0 NuSTAR 60002046003 2012-07-26 40.6/40.5 NuSTAR 60002046005 2012-12-24 66.2/66.3 NuSTAR 60002046007 2013-01-23 73.0/73.6 NuSTAR 60002046009 2013-02-12 69.7/69.5 XMM-Newton 0692840201 2012-07-25 133.9/133.9/118.2 XMM-Newton 0692840301 2012-12-24 121.6/121.6/107.8 XMM-Newton 0692840401 2013-01-23 125.0/125.0/92.8 XMM-Newton 0692840501 2013-02-12 122.4/122.5/115.8 ESO 203-1 NuSTAR 60374001002 2018-05-25 21.2/21.1 Chandra 7802 2008-01-17 14.8 CGCG 468-002W/CGCG 468-002E NuSTAR 60006011002 2012-07-23 15.5/15.5 Swift/XRT 49706(001–) 2013-04-17 81.5 (–011) 2014-11-11 IRAS F05189–2524 NuSTAR 60002027002 2013-02-20 22.9/23.2 NuSTAR 60002027004 2013-10-02 21.2/21.2 NuSTAR 60002027005 2013-10-02 7.9/8.0 NuSTAR 60201022002 2016-09-05 144.0/143.8 Chandra 2034 2001-10-30 19.7 Chandra 3432 2002-01-30 14.9 XMM-Newton 0085640101 2001-03-17 11.6/11.6/8.1 XMM-Newton 0722610101 2013-10-02 36.1/36.1/30.8 XMM-Newton 0790580101 2016-09-06 96.4/96.4/83.9 Suzaku 701097010 2006-04-10 78.2/48.7 IRAS F06076–2139/2MASS 06094601–2140312 NuSTAR 60370004002 2018-01-29 22.7/23.1 Chandra 15052 2012-12-12 14.8 NGC 2623 NuSTAR 60374010002 2018-05-24 38.7/38.6 Chandra 4059 2003-01-03 19.8 XMM-Newton 0025540301 2001-04-27 11.9/11.9/5.7 ESO 060-IG016 West/ESO 060-IG016 East NuSTAR 60101053002 2015-12-01 41.1/41.4 Chandra 7888 2007-05-31 14.7 IRAS F08572+3915 NuSTAR 50401004002 2019-04-04 211.2/209.3 NuSTAR 60001088002 2013-05-23 23.7/23.8 Chandra 6862 2006-01-26 14.9 (u; faint) XMM-Newton 0200630101 2004-04-13 28.2/28.3/23.5 XMM-Newton 0830420101 2019-04-05 57.6/57.5/51.0 XMM-Newton 0830420201 2019-04-07 61.2/61.2/51.9 Suzaku 701053010 2006-04-14 77.2/58.6 UGC 5101 NuSTAR 60001068002 2014-03-21 17.6/17.4 Chandra 2033 2001-05-28 49.3 XMM-Newton 0085640201 2001-11-12 33.9/34.0/26.5 Suzaku 701002010 2006-03-31 49.0/41.4

Table 3 continued 12 Yamada et al. Table 3 (continued)

Object Satellite ObsID Observation Date Net Exp. (1) (2) (3) (4) (5)

Suzaku 701002020 2006-10-31 42.2/31.6 MCG+08-18-012/MCG+08-18-013 NuSTAR 60101071002 2015-09-25 20.2/20.0 Chandra 15067 2013-06-03 13.8 MCG–01-26-013/NGC 3110 NuSTAR 60101072002 2015-11-12 18.9/18.9 Chandra 15069 2013-02-02 14.9 XMM-Newton 0550460201 2008-06-04 35.2/33.0/24.7 XMM-Newton 0550461001 2008-06-04 4.2/4.2/2.3 ESO 374-IG032 NuSTAR 60101055002 2016-01-14 51.1/51.7 Chandra 7807 2007-03-07 14.4 NGC 3256 NuSTAR 50002042002 2014-08-24 170.7/171.2 Chandra 835 2000-01-05 27.8 Chandra 3569 2003-05-23 27.2 Chandra 16026 2014-08-27 15.4 XMM-Newton 0112810201 2001-12-15 16.1/16.1/11.6 XMM-Newton 0300430101 2005-12-06 131.0/131.1/115.6 IRAS F10565+2448 NuSTAR 60001090002 2013-05-22 25.2/24.6 Chandra 3952 2003-10-23 28.9 XMM-Newton 0150320201 2003-06-17 30.7/30.7/26.4 Suzaku 702115010 2007-11-06 39.4/33.1 NGC 3690 West/NGC 3690 East NuSTAR 50002041002 2013-03-12 8.9/9.4 NuSTAR 50002041003 2013-03-13 59.8/59.7 Chandra 1641 2001-07-13 24.3 Chandra 6227 2005-02-14 10.2 Chandra 15077 2013-03-13 51.9 Chandra 15619 2013-03-12 38.5 XMM-Newton 0112810101 2001-05-06 21.3/21.3/15.4 XMM-Newton 0679381101 2011-12-15 11.2/11.2/8.5 ESO 440-58/MCG–05-29-017 NuSTAR 60101073002 2015-08-23 27.6/27.6 Chandra 15064 2013-03-20 14.8 IRAS F12112+0305 NuSTAR 60374005002 2018-01-17 18.9/18.8 Chandra 4110 2003-04-15 (u; faint) Chandra 4934 2004-07-17 (u; faint) XMM-Newton 0081340801 2001-12-30 22.3/22.3/17.9 NGC 4418/MCG+00-32-013 NuSTAR 60101052002 2015-07-03 47.2/47.0 Chandra 4060 2003-03-10 19.8 Chandra 10391 2009-02-20 5.7 Suzaku 701001010 2006-07-13 68.4/53.4 Mrk 231 NuSTAR 60002025002 2012-08-26 40.2/39.4 NuSTAR 60002025004 2013-05-09 27.5/28.2 NuSTAR 80302608002 2017-10-19 78.7/78.9 NuSTAR 90102001002 2015-04-02 31.1/31.2 NuSTAR 90102001004 2015-04-19 27.7/27.8 NuSTAR 90102001006 2015-05-28 30.4/30.3 Chandra 1031 2000-10-19 39.2 Chandra 4028 2003-02-03 39.7

Table 3 continued 13 Table 3 (continued)

Object Satellite ObsID Observation Date Net Exp. (1) (2) (3) (4) (5)

Chandra 4029 2003-02-11 38.6 Chandra 4030 2003-02-20 36.0 Chandra 11851 2010-07-11 4.8 Chandra 13947 2012-08-24 177.7 Chandra 13948 2012-08-27 173.8 Chandra 13949 2012-08-23 40.0 XMM-Newton 0081340201 2001-06-07 21.4/21.4/17.2 XMM-Newton 0770580401 2015-04-25 22.6/22.6/19.0 XMM-Newton 0770580501 2015-05-28 24.9/24.9/20.9 Suzaku 706037010 2011-04-27 197.5/75.2 NGC 4922S/NGC 4922N NuSTAR 60101074002 2015-11-17 19.9/19.7 Chandra 4775 2004-11-02 3.8 Chandra 15065 2013-11-02 14.9 Chandra 18201 2016-03-06 5.8 IC 860 NuSTAR 60301024002 2018-02-01 71.0/72.1 Chandra 10400 2009-03-24 19.2 IRAS 13120–5453 NuSTAR 60001091002 2013-02-25 26.2/26.2 Chandra 7809 2006-12-01 14.7 XMM-Newton 0693520201 2013-02-20 125.5/125.9/111.3 NGC 5104 NuSTAR 60370003002 2018-01-12 20.4/20.4 Swift/XRT 36966(001–) 2007-07-24 8.2 (–004) 2008-01-05 MCG–03-34-064 NuSTAR 60101020002 2016-01-17 76.6/78.1 Chandra 7373 2006-07-31 7.1 XMM-Newton 0206580101 2005-01-24 44.1/44.1/38.3 XMM-Newton 0506340101 2008-01-24 88.4/88.4/77.0 XMM-Newton 0763220201 2016-01-17 137.0/139.6/123.3 Suzaku 704022010 2009-07-01 (u; cont) Suzaku 707027010 2013-01-04 (u; cont) NGC 5135 NuSTAR 60001153002 2015-01-14 33.4/32.5 Chandra 2187 2001-09-04 29.3 Mrk 266B/Mrk 266A NuSTAR 60465005002 2019-02-08 29.7/30.1 Chandra 2044 2001-11-02 19.7 Mrk 273 NuSTAR 60002028002 2013-11-04 69.2/69.6 Chandra 18177 2016-09-06 59.9 Chandra 18178 2017-02-16 30.4 Chandra 19783 2017-02-18 31.8 Chandra 19784 2017-02-26 33.6 Chandra 20009 2017-02-14 34.3 Chandra 809 2000-04-19 (u; time-v) XMM-Newton 0722610201 2013-11-04 21.2/21.2/17.5 XMM-Newton 0101640401 2002-05-07 (u; time-v) XMM-Newton 0651360301 2010-05-13 (u; time-v) XMM-Newton 0651360501 2010-05-15 (u; time-v) XMM-Newton 0651360601 2010-05-17 (u; time-v)

Table 3 continued 14 Yamada et al. Table 3 (continued)

Object Satellite ObsID Observation Date Net Exp. (1) (2) (3) (4) (5)

XMM-Newton 0651360701 2010-06-26 (u; time-v) Suzaku 701050010 2006-07-07 79.9/77.4 IRAS F14348–1447 NuSTAR 60374004002 2018-01-27 21.1/21.0 Chandra 6861 2006-03-12 14.7 XMM-Newton 0081341401 2002-07-29 21.4/21.4/17.9 IRAS F14378–3651 NuSTAR 60001092002 2013-02-28 24.5/24.4 Chandra 7889 2007-06-25 13.9 IC 4518A/IC 4518B NuSTAR 60061260002 2013-08-02 7.8/7.8 XMM-Newton 0401790901 2006-08-07 11.5/11.5/8.8 XMM-Newton 0406410101 2006-08-15 24.4/–/21.2 Suzaku 706012010 2012-02-02 64.4/53.7 IRAS F15250+3608 NuSTAR 60374009002 2018-01-17 18.0/18.3 Chandra 4112 2003-08-27 9.8 XMM-Newton 0081341101 2002-02-22 19.2/19.2/15.3 Arp 220W/Arp 220E NuSTAR 60002026002 2013-08-13 66.1/66.0 Chandra 16092 2014-04-30 169.2 Chandra 16093 2014-05-07 66.7 Chandra 869 2000-06-24 (u; time-v) XMM-Newton 0101640801 2002-08-11 13.5/13.5/10.8 XMM-Newton 0101640901 2003-01-15 14.4/14.4/8.3 XMM-Newton 0722610301 2013-08-13 34.3/34.3/29.5 XMM-Newton 0205510201 2005-01-14 (u; highbg) XMM-Newton 0205510401 2005-02-19 (u; highbg) XMM-Newton 0205510501 2005-02-27 (u; highbg) Suzaku 700006010 2006-01-07 90.8/87.4 NGC 6240S/NGC 6240N NuSTAR 60002040002 2015-03-18 30.9/30.8 Chandra 12713 2011-05-31 145.4 Chandra 1590 2001-07-29 36.7 NGC 6285/NGC 6286 NuSTAR 60101075002 2015-05-29 17.2/17.2 Chandra 10566 2009-09-18 14.0 XMM-Newton 0203390701 2004-02-12 7.7/7.7/5.7 XMM-Newton 0203391201 2004-03-25 (u; highbg) IRAS F17138–1017 NuSTAR 60101076002 2015-06-26 24.8/25.2 Chandra 15063 2013-07-12 14.8 IRAS F18293–3413 NuSTAR 60101077002 2016-02-20 21.2/21.0 Chandra 7815 2007-02-25 14.0 Chandra 21379 2019-08-08 79.0 XMM-Newton 0670300701 2012-03-16 21.3/21.3/17.7 IRAS F19297–0406 NuSTAR 60374007002 2018-03-03 20.0/20.0 Chandra 7890 2007-06-18 16.4 NGC 6907/NGC 6908 NuSTAR 60370001002 2018-05-13 22.0/21.6 Swift/XRT 33513(003–) 2014-11-10 10.4 (–006) 2014-11-19 NGC 6921/MCG+04-48-002 NuSTAR 60061300002 2013-05-18 19.2/19.2

Table 3 continued 15 Table 3 (continued)

Object Satellite ObsID Observation Date Net Exp. (1) (2) (3) (4) (5)

XMM-Newton 0312192301 2006-04-23 13.7/13.7/10.8 Suzaku 702081010 2007-04-18 (u; cont) II Zw 096/IRAS F20550+1655 SE NuSTAR 60374002002 2018-03-28 29.0/29.1 Chandra 7818 2007-09-10 14.6 XMM-Newton 0670140101 2011-10-28 75.7/75.7/66.1 ESO 286-19 NuSTAR 60101054002 2015-07-30 44.5/44.0 Chandra 2036 2001-10-31 44.9 XMM-Newton 0081340401 2001-04-21 20.9/20.9/16.4 NGC 7130 NuSTAR 60061347002 2014-08-17 21.2/21.1 NuSTAR 60261006002 2016-12-15 40.2/39.9 Chandra 2188 2001-10-23 38.6 Suzaku 703012010 2008-05-11 44.5/34.2 NGC 7469 NuSTAR 60101001002 2015-06-12 21.6/21.5 XMM-Newton 0760350201 2015-06-12 –/–/62.6 IC 5283 NuSTAR 60101001002 2015-06-12 (u; cont) NuSTAR 60101001004 2015-11-24 (u; cont) NuSTAR 60101001006 2015-12-15 (u; cont) NuSTAR 60101001008 2015-12-22 (u; cont) NuSTAR 60101001010 2015-12-25 (u; cont) NuSTAR 60101001012 2015-12-27 (u; cont) NuSTAR 60101001014 2015-12-28 (u; cont) XMM-Newton 0112170101 2000-12-26 17.8/17.8/12.3 XMM-Newton 0112170301 2000-12-26 23.2/23.2/16.2 XMM-Newton 0760350201 2015-06-12 –/–/62.6 Suzaku 703028010 2008-06-24 (u; cont) ESO 148-2 NuSTAR 60374006002 2018-03-06 27.1/26.8 NuSTAR 60374006004 2018-03-29 19.1/19.0 Chandra 2037 2001-09-30 49.3 XMM-Newton 0081340301 2002-11-19 23.0/23.0/17.8 XMM-Newton 0109463601 2001-10-17 5.1/5.3/– XMM-Newton 0079940101 2005-10-22 18.4/18.4/– Swift/XRT 35164(001–) 2005-12-08 23.6 (–008) 2006-06-27 NGC 7591 NuSTAR 60370002002 2018-01-09 19.3/19.2 Chandra 10264 2009-07-05 4.9 NGC 7674/MCG+01-59-081 NuSTAR 60001151002 2014-09-30 52.0/51.9 XMM-Newton 0200660101 2004-06-02 10.1/10.1/8.1 Suzaku 708023010 2013-12-08 52.2/45.7 NGC 7679/NGC 7682 NuSTAR 60368002002 2017-10-06 22.4/21.7 XMM-Newton 0301150501 2005-05-27 19.7/19.8/16.2 Swift/XRT 88108002 2017-10-06 1.9

Note—Columns: (1) object name; (2) satellite name; (3) observation ID; (4) observation date in YYYY/MM/DD; (5) net exposure (FPMA and FPMB for NuSTAR; ACIS-S or ACIS-I for Chandra; MOS1, MOS2, and pn for XMM-Newton; each of available XIS 0, 1, 2, 3 and HXD-PIN for Suzaku; and XRT for Swift). The (u) means that the data are unused due to large time variability among the soft X-ray observations (time-v), too faint source or short exposure time (faint), contamination from brighter nearby sources (cont), or data with high background flaring throughout the observation (highbg). 16 Yamada et al.

We find that NuSTAR detects hard X-ray emission are taken into account by multiplying a constant fac- from 37 galaxies and the two inseparable dual-AGN sys- tor to the AGN transmitted component (Section 4.2.1). tems in the 8–24 keV band (or in the 10–40 keV band for For the sources whose NuSTAR total (source and back- MCG+12-02-001 and IRAS F14348–1447) at >3σ signif- ground) counts are <200 counts or the S/N ratios in the icance. These are considered to be good candidates of 8–24 keV band are <3σ, we employ the Cash statistics AGNs. Table4 summarizes the NuSTAR net count rates (Cash 1979)11, whereas we use χ2 statistics for the other (NCRNu) in the full (3–24 keV), soft (3–8 keV), and hard objects. (8–24 keV) bands, and the band ratio (the count-rate Excluding the 8 U/LIRG systems mentioned in Sec- ratio between the 8–24 keV and 3–8 keV bands) for all tion 2.5, we analyze the broadband spectra of the 31 Nu Nu Nu objects. The band ratio, BR (= NCR8−24/NCR3−8), systems that are significantly (>3σ) detected with NuS- is useful to identify obscured AGNs with a threshold of TAR in the 8–24 keV or 10–40 keV band, and those of BRNu > 1.7, corresponding to an effective photon index NGC 235, which is detected with Swift/BAT. Among of Γeff . 0.6 (Lansbury et al. 2017). Table4 also lists the 32 hard X-ray detected sources, we apply an AGN the observed 2–7 keV fluxes. These fluxes are calculated model (Section 4.2.1) to 30 sources that show hard X-ray from the broadband spectral analysis described in Sec- power law components. Whereas, we apply a starburst- tion 4.2. For the sources mentioned in Section 2.5, we dominant model (Section 4.2.2) to the other two sources, calculate the fluxes converted from the count rates of IC 1623A and NGC 3256, since their spectra show high Chandra, XMM-Newton, and/or Swift/XRT by assum- energy cutoff features around ∼10 keV and hence are ing a power-law photon index of 1.8. For the undetected likely dominated by X-ray binary (XRB) populations. sources, we constrain the 3σ upper limits by adopting The latter model is also adopted for the soft X-ray spec- the same conversion. tra of the 27 sources that are undetected with NuS- TAR in the 8–24 keV band. For 9 sources out of these 4.2. X-ray Spectral Model 59 sources, we introduce additional emission lines (Sec- We utilize xspec v12.10.1 (Arnaud 1996) for spectral tion 4.2.3) on the AGN or starburst-dominant model to fitting. Galactic absorption is considered with the phabs improve the spectral fit. model whose hydrogen column density is fixed at the value of Willingale et al.(2013). The abundances 4.2.1. AGN Model of Anders & Grevesse(1989) are assumed. The flux For the 30 AGNs detected in the hard X-ray band cross-calibration uncertainties among different instru- (see above), we apply the XCLUMPY model (Tani- ments are taken into account by multiplying constant moto et al. 2019), which is a Monte Carlo-based spectral factors. We set the constant values for NuSTAR/FPM model from clumpy tori in AGNs. The torus geometry and XMM-Newton/MOS to unity as references, whose and geometrical parameters are the same as those in the relative flux calibration is known to be accurate within CLUMPY (Nenkova et al. 2008a,b) model used for IR a few percent (Madsen et al. 2015, 2017), whereas those studies. As mentioned in Section1, many IR observa- of the other instruments are allowed to vary between tions suggest that AGN tori are not smooth but have 0.8 and 1.2. If a source is not detected with NuSTAR dusty clumpy structure (e.g., Krolik & Begelman 1988; in any bands, we adopt Chandra, XMM-Newton (MOS, Wada & Norman 2002; H¨onig& Beckert 2007). Recent pn), or Swift/XRT as the calibration reference in this X-ray spectral works also support the clumpy nature of priority order. We link that of Suzaku/HXD-PIN to AGN tori, as such models can explain a large amount 1.16 (1.18) times that of XIS-FI for the data observed of unabsorbed reflection components often observed in at the XIS (HXD) nominal pointing position, on the ba- obscured AGNs (e.g., Liu & Li 2014; Furui et al. 2016; sis of the calibration with the Crab . The XIS Tanimoto et al. 2018, 2019). Studies of the variability energy range of 1.6–1.9 keV is ignored for NGC 7674 of the line-of-sight column density using X-ray monitor- due to the large calibration error. ing data also support the clumpy structure (e.g., Lamer To obtain the highest quality spectrum from each in- et al. 2003; Puccetti et al. 2007; Risaliti et al. 2009, 2011; strument, we combine the spectra of all observations Maiolino et al. 2010; Markowitz et al. 2014; Laha et al. unless they show large time variability above ∼1 keV 2020). Thus, we regard this model as one of the most (listed in Table3 with the mark “time-v”). 10 The time realistic models. variability among the spectra of different instruments

11 The Cash statistic is also adopted for IRAS F08572+3915 where 10 When time variability is found only at lower energies, we use the the detection significance in the NuSTAR 3–8 keV band is <3σ combined spectra above ∼1–2 keV. level. 17

Table 4. X-ray Count Rates and NuSTAR Band Ratios in Our Sample

obs Nu Nu Nu Nu Gal Object F2−7 Facility NCR3−24 NCR3−8 NCR8−24 BR >3σ Det. NH (1) (2) (3) (4) (5) (6) (7) (8) (9)

NGC 34 1.7e-13 C 6.96 ± 0.49 3.04 ± 0.32 3.91 ± 0.37 1.29 ± 0.18 F S H 2.32 MCG–02-01-052 8.3e-15 C 0.14 ± 0.20 0.20 ± 0.15 <0.34 <1.70 ··· 3.51 MCG–02-01-051 5.7e-14 C 0.20 ± 0.19 0.17 ± 0.14 0.03 ± 0.12 0.18 ± 0.72 ··· 3.51 ESO 350-38 9.7e-14 C 0.62 ± 0.20 0.58 ± 0.16 0.04 ± 0.13 0.07 ± 0.22 F S 2.52 NGC 232 3.8e-14 C ··············· 1.49 NGC 235a 2.1e-12 C ··············· 1.48 MCG+12-02-001 1.0e-13 C 1.37 ± 0.23 0.92 ± 0.17 0.46 ± 0.15 0.50 ± 0.19 F S (H)b 36.1 IC 1623A 1.9e-13 C 2.88 ± 0.12 2.22 ± 0.09 0.66 ± 0.07 0.30 ± 0.03 F S H 1.45 IC 1623B (cont) C (cont) (cont) (cont) ······ 1.45 NGC 833 1.5e-13 C 11.87 ± 0.60 5.37 ± 0.41 6.42 ± 0.44 1.20 ± 0.12 F S H 2.73 NGC 835 6.0e-13 C 19.24 ± 0.76 6.63 ± 0.45 12.50 ± 0.61 1.89 ± 0.16 F S H 2.74 NGC 838 5.9e-14 C 1.16 ± 0.26 0.66 ± 0.18 0.45 ± 0.18 0.68 ± 0.33 F S 2.78 NGC 839 7.3e-14 C 0.37 ± 0.21 0.27 ± 0.14 0.08 ± 0.15 0.30 ± 0.58 ··· 2.80 NGC 1068 2.5e-12 XPN 132.40 ± 0.74 79.21 ± 0.57 52.86 ± 0.47 0.67 ± 0.01 F S H 3.22 UGC 2608 1.5e-13 X 9.55 ± 0.58 3.15 ± 0.38 6.41 ± 0.44 2.03 ± 0.28 F S H 20.3 UGC 2612 <1.5e-14 C <0.31 <0.42 <0.14 ······ 20.0 NGC 1275 3.4e-11 X 905.70 ± 3.58 637.10 ± 3.06 265.80 ± 1.84 0.42 ± 0.01 F S H 20.7 NGC 1365 7.0e-12 X 445.93 ± 1.80 246.43 ± 1.34 198.18 ± 1.20 0.80 ± 0.01 F S H 1.39 ESO 203-1 <1.1e-14 C <0.05 <0.11 <0.16 ······ 1.42 CGCG 468-002W 5.5e-12 XRT 214.10 ± 2.68 123.60 ± 2.03 89.91 ± 1.74 0.73 ± 0.02 F S H 31.1 CGCG 468-002E (cont) XRT (cont) (cont) (cont) ······ 31.1 IRAS F05189–2524 1.7e-12 C 72.86 ± 0.45 46.06 ± 0.35 26.54 ± 0.27 0.58 ± 0.01 F S H 1.80 IRAS F06076–2139 6.3e-14 C 3.46 ± 0.39 1.46 ± 0.25 1.99 ± 0.29 1.36 ± 0.31 F S H 9.56 2MASS 06094601–2140312 <1.1e-14 C (cont) (cont) (cont) ······ 9.56 NGC 2623 5.9e-14 C 1.98 ± 0.26 1.13 ± 0.18 0.84 ± 0.19 0.74 ± 0.21 F S H 3.54 ESO 060-IG016 West <8.5e-15 C (cont) (cont) (cont) ······ 7.26 ESO 060-IG016 East 1.1e-13 C 3.04 ± 0.26 1.68 ± 0.19 1.34 ± 0.18 0.80 ± 0.14 F S H 7.24 IRAS F08572+3915 1.2e-14 X 0.28 ± 0.06 0.11 ± 0.04 0.17 ± 0.04 1.55 ± 0.67 F H 2.17 UGC 5101 8.4e-14 C 15.02 ± 0.73 3.08 ± 0.37 11.85 ± 0.63 3.85 ± 0.51 F S H 3.33 MCG+08-18-012 <1.2e-14 C 0.06 ± 0.18 0.09 ± 0.13 <0.36 <4.00 ··· 1.74 MCG+08-18-013 3.7e-14 C 0.27 ± 0.18 0.33 ± 0.14 <0.27 <0.82 ··· 1.75 MCG–01-26-013 5.9e-15 C <0.28 <0.20 <0.24 ······ 3.90 NGC 3110 9.4e-14 C 0.43 ± 0.21 0.22 ± 0.14 0.22 ± 0.15 1.00 ± 0.93 ··· 3.89 ESO 374-IG032 1.2e-14 C 0.24 ± 0.12 0.21 ± 0.09 0.04 ± 0.08 0.19 ± 0.39 ··· 11.9 NGC 3256 4.5e-13 C 6.36 ± 0.17 4.92 ± 0.14 1.42 ± 0.09 0.29 ± 0.02 F S H 13.2 IRAS F10565+2448 3.8e-14 C 0.23 ± 0.19 0.41 ± 0.15 <0.15 <0.37 ··· 1.12 NGC 3690 West 8.7e-13 C 26.03 ± 0.46 11.90 ± 0.31 14.08 ± 0.34 1.18 ± 0.04 F S H 0.936 NGC 3690 East (cont) C (cont) (cont) (cont) ······ 0.935 ESO 440-58 1.7e-14 C 0.07 ± 0.15 0.07 ± 0.11 0.01 ± 0.10 0.14 ± 1.45 ··· 7.10 MCG–05-29-017 1.3e-14 C (cont) (cont) (cont) ······ 7.11

Table 4 continued 18 Yamada et al. Table 4 (continued)

obs Nu Nu Nu Nu Gal Object F2−7 Facility NCR3−24 NCR3−8 NCR8−24 BR >3σ Det. NH (1) (2) (3) (4) (5) (6) (7) (8) (9)

IRAS F12112+0305 1.3e-14 X 0.08 ± 0.19 0.22 ± 0.15 <0.22 <1.00 ··· 1.93 NGC 4418 1.4e-14 C 0.31 ± 0.12 0.19 ± 0.09 0.12 ± 0.09 0.63 ± 0.56 ··· 2.09 MCG+00-32-013 (cont) C (cont) (cont) (cont) ······ 2.09 Mrk 231 5.3e-13 C 22.50 ± 0.23 11.43 ± 0.17 11.01 ± 0.16 0.96 ± 0.02 F S H 0.992 NGC 4922S 4.1e-15 C (cont) (cont) (cont) ······ 0.966 NGC 4922N 8.0e-14 C 3.49 ± 0.42 1.59 ± 0.28 1.84 ± 0.30 1.16 ± 0.28 F S H 0.966 IC 860 <2.2e-14 C <0.27 <0.12 0.03 ± 0.07 >0.25 ··· 1.05 IRAS 13120–5453 1.7e-13 C 5.55 ± 0.41 2.92 ± 0.29 2.64 ± 0.29 0.90 ± 0.13 F S H 35.1 NGC 5104 2.6e-14 XRT 0.50 ± 0.21 0.15 ± 0.13 0.33 ± 0.16 2.20 ± 2.18 ··· 1.95 MCG–03-34-064 1.6e-12 C 86.39 ± 0.77 29.47 ± 0.45 56.78 ± 0.62 1.93 ± 0.04 F S H 6.44 NGC 5135 2.6e-13 C 13.48 ± 0.51 5.27 ± 0.33 8.19 ± 0.39 1.55 ± 0.12 F S H 6.02 Mrk 266B/Mrk 266Ac 1.7e-13 C 8.25 ± 0.44 4.29 ± 0.31 3.93 ± 0.31 0.92 ± 0.10 F S H 1.75 Mrk 273 2.0e-13 C 26.62 ± 0.47 9.48 ± 0.29 17.01 ± 0.37 1.79 ± 0.07 F S H 0.909 IRAS F14348–1447 2.5e-14 C 1.25 ± 0.32 0.79 ± 0.23 0.46 ± 0.22 0.58 ± 0.33 F S (H)b 10.8 IRAS F14378–3651 1.5e-14 C 0.28 ± 0.18 0.26 ± 0.13 0.02 ± 0.12 0.08 ± 0.46 ··· 8.22 IC 4518A 1.0e-12 X 143.00 ± 3.10 66.47 ± 2.11 76.07 ± 2.26 1.14 ± 0.05 F S H 13.1 IC 4518B 8.4e-15 XPN (cont) (cont) (cont) ······ 13.0 IRAS F15250+3608 8.7e-15 X 0.03 ± 0.19 0.09 ± 0.13 <0.33 <3.67 ··· 1.57 Arp 220W 7.1e-14 C 2.03 ± 0.19 1.54 ± 0.15 0.49 ± 0.12 0.32 ± 0.08 F S H 4.58 Arp 220E (cont) C (cont) (cont) (cont) ······ 4.58 NGC 6240S/NGC 6240Nc 1.0e-12 C 108.00 ± 1.36 26.96 ± 0.69 80.72 ± 1.17 2.99 ± 0.09 F S H 6.26 NGC 6285 1.4e-14 C 0.28 ± 0.20 0.42 ± 0.16 <0.22 <0.52 ··· 1.87 NGC 6286 5.0e-14 C 3.31 ± 0.43 0.93 ± 0.27 2.38 ± 0.33 2.56 ± 0.82 F S H 1.87 IRAS F17138–1017 8.8e-14 C 2.72 ± 0.34 1.65 ± 0.25 1.02 ± 0.23 0.62 ± 0.17 F S H 31.0 IRAS F18293–3413 1.2e-13 C 1.76 ± 0.27 1.33 ± 0.22 0.44 ± 0.16 0.33 ± 0.13 F S 14.3 IRAS F19297–0406 1.2e-14 C 0.38 ± 0.21 0.19 ± 0.14 0.20 ± 0.15 1.05 ± 1.11 ··· 28.2 NGC 6907 5.5e-14 XRT 1.06 ± 0.24 0.62 ± 0.17 0.42 ± 0.16 0.68 ± 0.32 F S 6.59 NGC 6908 (cont) XRT (cont) (cont) (cont) ······ 6.59 NGC 6921 1.8e-13 X 22.27 ± 0.91 4.47 ± 0.44 17.75 ± 0.80 3.97 ± 0.43 F S H 34.4 MCG+04-48-002 1.1e-12 X 34.81 ± 1.00 10.00 ± 0.55 24.72 ± 0.84 2.47 ± 0.16 F S H 34.5 II Zw 096 8.7e-15 C (cont) (cont) (cont) ······ 9.16 IRAS F20550+1655 SE 5.8e-14 C 1.22 ± 0.21 0.83 ± 0.16 0.39 ± 0.14 0.47 ± 0.19 F S 9.16 ESO 286-19 4.3e-14 C 0.64 ± 0.14 0.42 ± 0.11 0.20 ± 0.10 0.48 ± 0.27 F S 3.76 NGC 7130 1.5e-13 C 10.75 ± 0.34 2.89 ± 0.19 7.86 ± 0.28 2.72 ± 0.20 F S H 2.11 NGC 7469 1.9e-11 XPN 588.90 ± 3.75 365.60 ± 2.95 221.60 ± 2.30 0.61 ± 0.01 F S H 5.39 IC 5283 <1.1e-14 X (cont) (cont) (cont) ······ 5.39 ESO 148-2 1.3e-13 C 0.86 ± 0.15 0.55 ± 0.11 0.31 ± 0.10 0.56 ± 0.21 F S H 1.68 NGC 7591 <4.4e-14 C <0.53 <0.33 0.03 ± 0.14 >0.09 ··· 7.52 NGC 7674 3.5e-13 X 24.22 ± 0.52 10.96 ± 0.35 13.15 ± 0.38 1.20 ± 0.05 F S H 5.20 MCG+01-59-081 <1.6e-14 X (cont) (cont) (cont) ······ 5.19

Table 4 continued 19 Table 4 (continued)

obs Nu Nu Nu Nu Gal Object F2−7 Facility NCR3−24 NCR3−8 NCR8−24 BR >3σ Det. NH (1) (2) (3) (4) (5) (6) (7) (8) (9)

NGC 7679 4.2e-13 X 48.01 ± 1.08 28.53 ± 0.83 19.34 ± 0.70 0.68 ± 0.03 F S H 6.25 NGC 7682 1.5e-13 X 12.07 ± 0.60 5.09 ± 0.39 6.88 ± 0.45 1.35 ± 0.14 F S H 6.40

Note—Columns: (1) object name; (2–3) observed 2–7 keV flux corrected for Galactic absorption in units of erg s−1 cm−2, and the facility of the soft X-ray data. Fluxes are calculated from the best-fitting spectral model described in Section 4.2. For the sources mentioned in Section 2.5 and the undetected sources (given as upper limits), they are converted from the X-ray count rates with the HEASARC tool WebPIMMS (v4.11a; https://heasarc.gsfc.nasa.gov/cgi-bin/Tools/w3pimms/w3pimms.pl) assuming a power-law of Γ = 1.8 with Galactic absorption. The adopted soft X-ray observations of Chandra (C), XMM-Newton/MOS (X), pn (XPN), and Swift/XRT (XRT) are listed in Column (3). (4–6) background-subtracted net count rates of combined NuSTAR observations in the full (3–24 keV), soft (3–8 keV) and hard (8–24 keV) bands in units of 10−3 cts s−1; (7) NuSTAR Band ratio (i.e., the ratio of 8–24 keV and 3–8 keV count rates); (8) NuSTAR >3σ detection in the full (F), soft (S), and hard (H) bands; (9) hydrogen column density of Galactic absorption in units of 1020 cm−2 (Willingale et al. 2013). The (cont) means that the value is smaller than that of the , and is difficult to estimate due to its contamination. The error is 1σ, and the upper and lower limits are 3σ levels. aNuSTAR has not observed NGC 235, but Swift/BAT detects it in the 14–195 keV band at a 25.51σ level (Oh et al. 2018). b For MCG+12-02-001 and IRAS F14348–1447, the NuSTAR net count rates in the 8–24 keV band are 2.98σ and 2.08σ levels, while those in the 10–40 keV band are 3.37σ and 3.06σ levels, respectively. c The system hosting two bright AGNs whose emissions could not be spatially resolved with NuSTAR.

normalization is linked to that of the direct component, while the photon index (Γbin) is allowed to vary between The spectral model in the xspec terminology is rep- 1.5 and 3.0.12 The const3 is multiplied, which gives a resented as: fraction of the unabsorbed emission (fbin) relative to the transmitted AGN component at 1 keV, containing both const1 ∗ phabs ∗ zphabs∗ the XRB and scattered AGN components. Its range (const2 ∗ zphabs ∗ cabs ∗ zcutoffpl + const3 ∗ zcutoffpl is restricted within 0%–20%.13 For the three stage- D mergers whose const3 values cannot be constrained + atable{xclumpy R.fits} + atable{xclumpy L.fits} (IRAS F08572+3915, Arp 220W, and IRAS F17138– + apec[×1−3]). (2) 1017), we adopt 10% as a typical value obtained from the other stage-D mergers. In the fist term, const1 and phabs represent the instru- The third and fourth terms are the table mod- mental cross-normalization factor and Galactic absorp- els of XCLUMPY, providing the reflection contin- tion, respectively. The zphabs accounts for an absorp- uum (xclumpy R.fits) and fluorescence emission lines tion of the host galaxy when required (only for NGC (xclumpy L.fits), respectively. The free parameters are 3690W, UGC 5101, and IRAS 13120–5453). The first the hydrogen column density along the equatorial plane term represents the direct component modeled by an Equ (N : 1023–1026 cm−2), torus angular width (σ: 10◦– absorbed power-law with an exponential cutoff, which H 70◦), and inclination of the observer (i: 20◦–87◦).14 is fixed at 300 keV (e.g., Dadina 2008). The photon in- When these values are not well constrained, we first fix dex (ΓAGN) is set to be a free parameter between 1.5 and 2.5. When it cannot be well constrained, we fix it at 1.8 as a typical value in AGNs (e.g., Ueda et al. 2014; Ricci 12 This is because in reality the “scattered” component may contain et al. 2017c). We consider Compton scattering effect many soft X-ray emission lines from a photoionized plasma that are hard to be resolved with CCD spectra, making the apparent out of the line of sight (cabs), whose hydrogen column slope (i.e., that obtained with a simple power law model) steeper density (NH) is tied to that of photometric absorption than that of the direct component. Time 13 (zphabs). The const2 factor (C ) is a constant to The typical scattering fraction is .5% for the obscured AGNs with N LoS ≥ 1022 cm−2 from the 70-month Swift/BAT catalog take account of time variability among different instru- H (Gupta et al. 2021), while the fbin for AGNs in stage-D mergers ments. This is allowed to vary within 0.1–10 (i.e., a are ∼10%, indicating that the component of XRBs may signifi- factor of <10 in variability) in order to avoid unrealistic cantly affect the values (see Section 6.3). 14 solutions. The inner (rin = 0.05 pc) and outer radii (rout = 1.00 pc), the The second term, an unabsorbed cutoff power-law, radius of each clump (Rclump = 0.002 pc), the number of the clumps along the equatorial plane (N Equ = 10), and the index represents the scattering component from the AGN clump of radial clumpy distribution (q = 0.5) are fixed. and/or the emission from XRBs in the host galaxy. The 20 Yamada et al. the inclination to either 30◦, 60◦, or 80◦ that gives the 10 keV.16 Moreover, there are little signatures of AGNs smallest χ2 or C value. Furthermore, if σ is not well in these starburst-dominant and hard X-ray undetected determined, we fix it to be 20◦, a typical value obtained sources based on multiwavelength observations as dis- from a local AGN sample (Ogawa et al. 2021).15 We cussed in AppendixB. 17 LoS link the line-of-sight column density (NH ) in the first The starburst-dominant model is described as term to the value converted from these torus parame- ters by following Equation (3) in Tanimoto et al.(2019). const1 ∗ phabs ∗ zphabs ∗ (zcutoffpl + apec[×1−2]). (3) LoS When NH is found to be variable among the observa- tion epochs of different satellites, it is set to be a free The cross-normalization (const1) and Galactic absorp- tion (phabs) are the same as those in the AGN model. parameter. The normalizations and photon indices are The absorption by the host galaxy (zphabs) is adopted fixed to those of the direct component. The fifth term is optically-thin thermal emission in the host galaxy mod- only for NGC 3256. The first term represents emission from XRBs in the host galaxy. We note that this com- eled by the apec code (Smith et al. 2001). Whenever ponent would include a scattered component from the necessary, we consider two or three components with different temperatures. AGN if present. The photon index (Γbin) is allowed to The best-fit spectra of the 30 AGNs are shown in Fig- vary between 1.5 and 3.0. The second term is optically- thin thermal emission modeled by apec. ures C1–C5. The best-fit parameters, observed X-ray fluxes, observed X-ray luminosities, and the equivalent The best-fit spectra are shown in Figures C6–C10. width (EW) of the Fe Kα line are summarized in Ta- The best-fit parameters, observed fluxes, and observed luminosities are listed in Table6. AppendixB compares ble5, including the the results of UGC 2608, NGC 5135 the results of our spectral analysis with those of previous (Yamada et al. 2020), and NGC 7469 (Ogawa et al. 2021) analyzed with the XCLUMPY model. Thus, we studies for the individual sources. finally obtain X-ray spectral results of 40 AGNs, con- 4.2.3. Additional lines sisting of 33 AGNs analyzed with XCLUMPY and 7 AGNs for which we refer to the literature (NGC 1068, The XCLUMPY model contains fluorescence lines NGC 1275, NGC 1365, Mrk 266B/Mrk 266A, and from elements with atomic numbers up to Z = 30, NGC 6240S/NGC 6240N). Comparison of our results among which the Fe Kα line at 6.4 keV is the strongest. with previous works for individual sources is summa- Besides them, we also include Gaussian components rized in AppendixB. (zgauss in xspec) to model other prominent emission lines when required. In particular, emission lines from highly ionized iron ions (Fe XXV and Fe XXVI) at ∼6.7–7.0 keV are often detected from C-GOALS objects, 4.2.2. Starburst-dominant Model which are most probably produced by highly ionized in- We apply a starburst-dominant model to the two terstellar medium energized by starburst activities (see sources detected with NuSTAR in the 8–24 keV band e.g., Iwasawa et al. 2009, 2011a; Lindner et al. 2012; (IC 1623A and NGC 3256), and to the 27 sources not Gilli et al. 2014). Also, Si XIII line at 1.86 keV is often detected with NuSTAR in this band. Hereafter, we observed, which originates from AGN photoionized gas call these two and 27 sources as “starburst-dominant and/or thermal emission from the starburst region. Ac- sources” and “hard X-ray undetected sources”, respec- cordingly, we add these highly-ionized Fe and Si Kα lines tively. The two starburst-dominant sources show the if they are found to significantly improve the fit. When smallest values of the band ratio, BRNu ≈ 0.3, among necessary, we also consider other emission lines (O VIII the hard X-ray detected sources. This means that their Kα at 0.654 keV, Mg XI Kα at 1.342 keV, and Ni Kα at spectra are steeper than those of AGNs in the 3–24 keV 7.48 keV). The best-fit values of these additional lines, range (see also Section 5.1). Actually, their broad- adopted for nine sources, are listed in Table7. band spectra cannot be well reproduced with the AGN model because of the high energy cutoff features around

15 The averaged value of σ that we can constrain, ∼22◦, is consis- 16 Nu tent with the adopted typical value (20◦). We note that, even Although Arp 220W also shows BR ≈ 0.3, it does not show if different values of σ, 10◦ and 30◦, are adopted, the main re- such a cutoff feature at ∼10 keV. If we fit the spectrum with sults are almost unchanged except for the torus covering factors. zcutoffpl, we obtain Ecut > 92 keV (see AppendixB). Thus, the torus covering factors are not calculated when σ is 17 Although IC 1623B might have an AGN, its X-ray emission is fixed (Section 5.3.4). much weaker than that of IC 1623A (e.g., Grimes et al. 2006). 21 4 3[S] 58 65[B] 01 07 02[X] 08[X] ] ...... ] ] ] ] ] 2 ) ] 2 0 0 0 2 2 2 2 2 2 ν S] χ − +3 − +0 − +0 − +0 χ χ χ χ χ B] / χ / 45 01 01[X] 77[X] . . . . 7 9[X 11 11[X . . 0 0 . (C/C . /10.3 /5.46 /0.11 /0.58 4 Time 0 Time H ··· ··· ··· − +0 − +0 2 ν +4 − − +0 C N χ 5 0[X] . . / 56 21 08 67[X] 19[C] 08[C] 3 ...... 0.16 0.45 2 60.1 0 0 0 0.44 +5 − χ − +0 +0 − − +0 13.6 3.55 1.95 0.44 7 0 32 10 . 6 6 3 5 . 9 3 5 2 ...... 5 0 0 0 0 0 0 − +8 − − +0 − +0 − +1 − +0 − (f) bin BAT ······ 1 f EW C 2.3 0.6 0.6 1.5 10.4 1.20 1.20 ) 50 39 09 59 14 15 25 21 15 14 25 ...... − 0 0 0 0 1 0 obs 10 +0 − +0 − − − +0 − +0 − AGN bin XRT ··· ········· L Γ C 3.00 1.05 2.27 2.79 3.00 2.49 (=Γ log 4 3 1 0 03 10 . . 4 1 8 . . 8 7 3 . 5 ...... 4 4 0 − 0 2 0 21 +6 − obs 2 +6 − +8 − BI − +1 − +5 − +1 − +45 − AGN L C 33 A 101 5.1 5.1 9.5 15.4 10.2 log 1.20 2 06 10 17 02 16 04 22 11 09 02 23 21 07 24 − ...... 5 0 0 0 0 0 0 0 . FI obs 0 +0 − +0 − +0 − +0 − +0 − +0 − +0 − ············ ····················· ································· AGN L C 43.24 43.24 43.37 8042.14 42.34 1696.2/1.09 [ 42.48 11 423.8/1.10 [ Γ 1.50 1.20 1.66 1.86 1.66 1.67 1.77 1.98 log 2 06 05 01 05 07 20 10 07 06 01 05 06 − ...... 5 continued 0 0 0 0 0 0 0 . (f) (f) (f) (f) (f) (f) (f) bin 0 pn +0 − +0 − +0 − +0 − − − +0 − ··· L C 60 60 45 30 80 30 60 Stage-A 0.93 0.95 1.13 1.04 1.20 1.20 1.14 log Table 5 2 8 4 1 3 1 5 4 7 8 2 2 . . 8 7 01 11 05 ...... − . . . . . 0 1 4 1 5 4 9 0 . +5 +1 − +0 − +5 − +2 − apec 0 +18 − +43 − +0 +0 − σ i ······ ACIS L C 10.0 12.4 12.4 37.9 13.7 22.4 20.0 0.80 0.81 log 4 . 9 0 . 50 . 0 8 5 6 1 6 5 2 8 ...... 73 − 22 3 0 0 1 . Summary of the Best-fit Spectral Parameters for AGNs 3 − obs +68 − 10 +0 +8 − +2 − +1 − +3 − Equ H ······ ··· 11.36 41.29 41.35 41.62 42.12 42.92 248 202.2/1.10 [ 11.28 40.34 40.02 40.52 41.51 42.33 60 338.3/1.05 [ 11.62 39.53 39.67 39.92 41.41 41.9511.07 40.24 49 40.37 40.62 185.9/1.18 [ 41.46 42.57 385 142.9/1.13 [ 11.09 40.22 40.37 40.6010.41 41.19 42.58 103911.34 40.52 42.2/0.84 [ kT F N 0.1 4.4 2.2 2.1 3.6 − − − − − − − 32.0 log 100.0 Table 5 02 04 03 07 10 . . . . 0 0 − 2 obs 2 − +0 − +0 Host H ··· ··· ··· ··· ··· ··· ··· ······ ········· ·················· F 12.14 12.10 12.16 12.16 12.46 10.54 11.47 kT N − − − − − − − log 0.11 0.41 9 8 2 . 8 . 1 5 9 2 8 5 . 0 05 09 09 07 16 18 05 06 10 33 49 22 ...... − ...... 31 1 1 1 5 8 0 0 0 0 0 0 1 . − +27 obs +1 − +0 − +2 − 0 − +14 +0 − +0 − +0 − +0 − +0 − +0 − LOS H ············ 3e-7 F 12.67 13.10 13.65 13.02 13.07 10.54 11.68 kT (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) 0.0015 N < − − − − − − − < 0.77 0.89 0.64 0.38 0.36 0.49 log (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) Object NGC 833NGC 835 26.1 NGC 6921 29.8 MCG+04-48-002 173.1 72.7 NGC 7469 NGC 7674NGC 7679 29.6 22 Yamada et al. 04 05[S] . . ] ] ] ) ] ] 0 2 2 2 2 2 ν − +0 χ χ χ χ χ 3 6 4[C] 7[X] 11 17[S] 17 21[X] ...... 2 1 0 0 (C/C /0.82 +2 − Time − +1 Time H +0 − ··· ··· ··· ··· ··· ··· ··· − +0 2 ν C N χ 03 / 03[X] 29.3 21.6 . . 0.52 0.51 2 0 χ +0 − 0.34 7 . 17 05 06 5 2 4 1 3 6 2 4 3 8 2 2 4 9 ...... 0 10 0 0 1 0 5 3 1 +0 +0 − − − − +1 − − +4 − +0 +0 +0 +5 − +1 − bin BAT f EW C 5.6 2.3 0.5 0.6 9.6 3.3 0.80 1.14 20.0 ) 3.7 50 06 10 16 27 18 01 47 34 20 27 ...... − 0 0 0 0 0 (f) (f) obs 10 +0 +0 − − +0 − − +0 − +0 AGN bin XRT ··· ······ L Γ 1.8 1.8 C 0.80 1.56 3.00 1.66 2.20 1.90 (=Γ log 3 7 2 4 3 ) 03 10 . . 5 1 5 4 . . 6 1 5 6 . 0 ...... 1 5 . 0 − 0 0 0 0 13 FI 1 obs 2 +2 − +5 − BI − +0 − +0 − +0 − +3 − +23 − C +38 − AGN L C 43 A 3.1 4.0 0.6 1.5 (= 2.5 23.2 35.0 log 1.20 2 04 29 10 03 07 77 03 11 05 06 − ...... 5 0 0 0 0 0 . (f) (f) (f) (f) FI obs 0 +0 − +0 − +0 − +0 − +0 − ············ ··············· AGN L C 1.8 1.8 1.8 1.8 Γ 1.50 1.20 1.17 1.68 1.63 1.81 log 2 04 16 11 04 11 13 − ...... 5 continued 0 0 0 . (continued) (f) (f) (f) (f) (f) (f) (f) (f) bin 0 pn +0 − +0 − +0 − ··· ···································· ·················· L C 60 60 60 60 60 60 80 60 Stage-B Stage-C 41.11 41.78 42.82 43.12 71 442.4/1.08 [ 40.86 40.86 40.83 41.20 222 262.8/0.90 [C] 40.74 40.75 41.78 42.11 83 18.4/1.15 [ 40.51 40.52 41.53 42.28 177 249.8/0.92 [C] 1.07 1.09 0.99 log Table 5 2 2 0 3 9 9 9 8 . Table 5 14 29 05 15 8 ...... − . . . . . 2 1 0 5 0 35 0 . +4 − +0 − +0 − (f) (f) (f) (f) apec 0 +0 +0 − +9 − − (f) (f) σ i ··· ··· ··· ··· ACIS 1 1 L 20 20 20 20 C 19.0 14.7 17.5 0.80 0.94 60.2 1.20 log 8 9 . 50 . 1 7 4 3 8 7 3 0 0 4 4 3 1 9 ...... − 38 0 3 0 0 0 0 1 3 obs +32 − 10 +1 − +6 − +1 − +0 − +1 − +3 − +1 − Equ H ······ 10.80 40.71 40.42 40.90 42.45 42.98 105 772.6/1.12 [ 10.71 11.79 39.82 40.12 40.30 41.38 42.02 231 58.8/1.20 [ 10.61 40.49 40.73 40.95 42.47 43.43 21611.88 40.79 119.8/1.17 [ 40.36 40.93 40.84 42.00 559 893.4/1.01 [C] 12.56 12.22 12.54 kT F N 0.5 6.2 1.0 0.8 3.2 1.8 4.0 − − − − − − − − 67.1 log 08 06 10 . . 0 − 2 obs 2 − +0 Host H ······ ··············· ··· ··· ··· ··· ··· ··· ··· ··· F 11.32 11.01 12.42 12.91 11.56 13.03 12.88 12.96 kT N − − − − − − − − log 0.26 1 4 6 7 . . 2 . 0 . 0 0 1 9 5 3 5 . . 10 04 06 14 06 04 35 12 . . . 1 9 . . . 1 0 − ...... 34 7 6 0 5 277 0 0 0 0 12 0 2 1 . − +26 obs +6 − +8 − +0 − 0 +268 − +0 − +0 − +0 − +0 − − +24 +0 − +4 − LOS H ········· ····················· ········· ········· F 12.87 12.04 13.52 12.88 13.10 12.95 13.93 13.99 kT (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) N − − − − − − − − 51.4 0.90 0.79 0.26 0.92 log † (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) Object NGC 7682NGC 235 38.2 CGCG 468-002W 1.5 ESO 060-IG016 East 8.4 IC 4518ANGC 6286 17.1 MCG+12-02-001 140.2 707.5 IRAS F06076–2139 42.2 23 4[XRT] 01 02[X] ] . . . 1 ] ] ] S] 2 . ) 0 2 2 2 / ν χ − +0 18 χ χ χ X / 7[S] +975 − . 7 . 4 1[C . 60 . (C/C /0.90 Time Time +700 − H ··· ··· ··· ··· ··· ··· 19 2 ν /24.6 C +27 − N χ X] / 03 03[C] / . . 2 0 299.3 χ +0 − 6 9[C 147.9 . . 0 +0 − 0.87 2.7 7 6 23 . 0 2 7 7 5 1 . 0 3 8 5 5 1 ...... 7 0 2 3 1 0 1 0 +4 − (f) − +3 − − +2 − +0 − +6 +2 − +0 − (f) bin BAT ······ 1 f EW 10 C 4.7 7.9 1.6 7.2 2.3 1.1 15.4 1.20 50 13 16 15 06 29 08 49 10 12 26 08 32 19 08 ...... − 0 0 0 0 0 0 obs 10 +0 +0 +0 − +0 − +0 − +0 − +0 − +0 − (f) bin XRT ··· ··· 1 L Γ C 1.50 1.50 1.65 1.66 1.79 1.70 1.84 2.92 log 7 1 21 03 09 04 01 09 10 . 6 2 8 8 1 . 7 0 4 2 1 ...... 1 0 0 0 58 − 0 2 0 0 0 obs 2 +1 − BI +0 − +0 − +0 − +132 − +0 − +6 − +1 − +1 − +0 − ············ AGN L C A 2.8 7.6 2.4 1.6 0.3 111 35.3 log 0.24 1.19 0.93 2 21 02 13 07 17 21 02 08 07 − ...... 5 0 0 0 0 . (f) (f) (f) (f) (f) FI obs 0 +0 +0 − +0 − +0 − +0 − (f) ··············· ······ ··············· ··············· AGN 1 L C 1.8 1.8 1.8 1.8 1.8 Γ 1.50 2.23 2.19 1.12 0.88 log 2 4 1 . . 11 11 02 11 01 12 09 02 11 01 − ...... 5 continued 0 0 15 0 0 0 . (continued) (f) (f) (f) (f) (f) (f) (f) bin 0 pn +0 − +0 − +21 − +0 − +0 − +0 − (f) ·················· 1 L C 60 30 60 80 60 60 60 40.58 40.59 41.13 41.88 170 1042.0/0.91 [C] Stage-D 1.01 1.11 65.9 0.92 1.02 1.04 log Table 5 2 2 7 6 7 5 7 Table 5 08 08 14 03 07 02 21 09 04 03 10 ...... − ...... 1 9 0 5 0 0 0 0 0 . +6 − +8 − +0 − (f) (f) (f) (f) (f) apec 0 +0 +0 − +0 − +0 − +0 − +0 − (f) σ i ··· ACIS 1 L 20 20 20 20 20 C 11.2 44.9 11.8 0.80 0.88 0.95 1.16 1.13 0.87 log 4 . 6 5 8 . 50 . . 3 01 01 9 3 0 2 7 1 0 9 4 3 ...... 84 − 4 0 23 0 2 1 0 2 3 − obs +28 − +0 − +48 − 10 +1 − +4 − +0 − +0 − +5 − Equ H ··· 12.07 40.29 40.48 40.69 41.12 42.03 261 323.3/0.83 [C] 12.71 39.60 39.91 40.10 40.87 41.17 61 597.9/0.90 [C] 12.47 41.05 41.0611.91 41.35 40.20 41.43 40.61 42.19 40.75 277 41.31 42.02 2323.2/0.97 [C] 163 103.4/1.04 [ 11.23 42.02 41.10 41.29 41.36 42.14 39111.35 612.1/1.18 [ 41.03 41.54 41.73 43.15 43.2811.33 40.44 25 40.95 40.96 3522.7/1.17 [ 41.96 43.21 249 172.6/1.02 [ 13.01 kT F N 4.8 7.2 2.0 0.6 8.0 − − − − − − − − 18.0 0.04 49.0 log 100.0 05 05 01 01 05 06 02 01 10 ...... 0 0 0 0 − 2 obs 2 +0 − − +0 − +0 − +0 Host H ······ ······ ······ ······ ··· ··· ··· ··· ··· ··· ······ F 12.96 13.01 13.75 12.62 13.22 12.00 11.46 12.56 kT N − − − − − − − − log 0.45 0.11 0.26 0.11 7 6 6 0 1 3 2 . . 3 . . . . 6 3 6 3 . 9 29 18 04 10 03 13 09 39 29 04 08 03 13 08 . . . 1 1 . 1 5 − ...... 49 47 1 5 9 0 0 0 0 0 0 0 0 2 1 . 21 28 − − +60 +45 obs +4 − 0 − +10 +0 − +0 − +0 − +0 − +0 − +0 − +0 − +0 − +4 − LOS +285 − +129 − H ··············· F 13.41 13.79 14.31 13.18 13.31 12.07 12.89 13.58 kT (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) N − − − − − − − − 1.27 1.00 0.79 0.77 0.95 0.89 0.96 log (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) Object NGC 3690 West 302.6 NGC 4922NESO 148-2 75.9 NGC 158.5 34IRAS F05189–2524 50.3 7.5 NGC 2623IRAS F08572+3915 84.6 6.0 UGC 5101 96.3 24 Yamada et al. 9 0[S] . . 03 03[X] ] ] . . ] ] ] 27 2 2 ) ] 0 2 2 2 +54 − 2 ν χ χ − +0 χ χ χ X] χ / 18 18[C] . . 0 7[C . . 0 (C/C /0.63 2 /172.8 Time Time H ··· ··· ··· ··· ··· ··· ··· +0 − 2 ν +1 − C N χ 3[C] / 04 05[C] . 9 . . 1.46 2 . 56.1 0 9 χ +0 − +11 − 0.70 92.5 2 8 9 . 3 11 15 7 12 . 9 3 1 . 5 4 1 . 6 ...... 0 . 12 0 0 0 0 8 − +0 (f) (f) +0 − +3 +0 − +1 − +0 − − +0 bin +10 − BAT f EW 10 10 C 2.3 0.6 0.6 9.7 16.6 0.80 16.3 1.01 50 01 24 59 12 10 02 17 02 12 24 13 ...... − 0 0 0 0 obs 10 +0 +0 +0 +0 − +0 +0 − − +0 − bin XRT ··· ······ ········· ········· L Γ C 1.50 1.50 1.50 1.50 1.51 1.74 2.87 3.00 log 05 12 11 10 10 05 10 5 7 1 6 3 1 1 2 1 6 5 1 ...... 19 0 0 0 0 − 0 3 0 0 0 0 41 obs 2 +20 − BI +0 − +0 − − − +6 − +6 − +0 − +7 − +0 − +0 − +54 − AGN L C 96 A 127 2.1 9.7 2.1 1.0 1.6 2.1 log 1.10 1.09 1.20 1.20 2 08 03 13 06 14 05 06 09 03 13 04 − ...... 5 0 0 0 0 0 0 . (f) (f) (f) (f) (f) FI obs 0 +0 +0 − +0 − − − +0 − +0 − ··············· ········· ··············· AGN L C 1.8 1.8 1.8 1.8 1.8 Γ 1.50 1.02 1.06 1.20 1.20 1.71 2.01 log 2 05 07 03 15 05 01 16 05 07 03 15 06 01 − ...... 5 continued 0 0 0 0 0 0 0 . (continued) (f) (f) (f) (f) (f) (f) (f) (f) bin 0 pn +0 − +0 − +0 − +0 − +0 − +0 − − ·················· L C 80 60 60 80 60 60 60 80 40.49 40.50 40.91 41.38 120 283.9/0.81 [C] Stage-N 1.01 1.00 1.00 0.97 0.97 0.98 1.20 log Table 5 2 5 0 5 2 9 9 7 Table 5 11 06 06 05 03 15 09 07 02 05 ...... − ...... 6 2 0 5 0 0 0 0 . +8 +5 − +1 − +0 − (f) (f) (f) (f) apec 0 +0 +0 +0 − +0 − +0 − +0 − (f) σ i ··· ACIS 1 L 20 20 20 20 C 10.0 22.6 17.3 20.1 0.80 0.80 1.11 0.92 1.18 0.90 log 3 5 . . 5 50 . 5 8 01 01 7 2 4 3 4 3 . . 0 ...... 61 69 − . 4 0 0 0 1 9 3 1 − − obs +15 − +0 − 10 +8 − +2 − +1 − +19 − Equ H +19 − ··· ··· 11.29 41.16 41.20 41.48 42.34 43.22 148 349.5/1.12 [ 12.15 42.09 41.20 41.33 41.65 42.18 107 327.6/1.15 [ 11.56 41.11 41.49 41.64 42.56 43.05 81 1301.7/1.19 [ 12.45 11.48 41.2010.73 41.18 41.40 41.49 41.02 41.41 41.57 42.60 42.00 1430 43.06 425 75.1/1.04 [ 2410.3/1.20 [ 12.57 40.24 40.41 40.64 40.89 41.29 120 350.6/1.20 [ 12.64 41.08 41.50 41.64 41.85 42.57 232 776.9/0.91 [C] kT F N 15 2.1 0.5 9.2 − − − − − − − − 1.6 10.0 0.12 log 100.0 100.0 04 07 01 18 04 49 01 15 10 ...... 0 0 0 0 − 2 obs 2 − − +0 +0 − +0 +0 − Host H ······ ········· ······ ··· ··· ······ ··· ··· ··· ··· ··· F 12.15 12.68 12.04 12.92 11.77 12.67 12.97 13.34 kT N − − − − − − − − log 0.18 0.31 0.82 0.43 5 1 . . 5 4 6 0 2 . . . . 8 4 5 8 12 05 03 06 15 05 23 10 05 03 14 08 04 25 . . 2 . . 2 22 − ...... 643 20 55 2 2 5 0 0 0 0 0 0 0 310 0 1 − . − − − +21 +95 obs +5 − +2 − 0 +0 − +0 − +0 − +0 − +0 − +0 − +0 − +700 − +0 − LOS H ········· F 13.04 13.00 12.97 13.33 12.22 12.60 13.22 13.59 kT (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) N − − − − − − − − 1.26 1.00 0.81 0.82 1.93 0.91 0.77 log (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) Object Mrk 231IRAS 13120–5453 164.8 8.5 Mrk 273IRAS F14348–1447 128.3 49.6 Arp 220WIRAS F17138–1017 1000.0 1000.0 UGC 2608MCG–03-34-064 540 98.4 25 ] ] ) 2 2 ν χ χ (C/C Time Time H ··· ··· ··· 2 ν C N χ 22 / 2 χ ]. The 2 − line in [eV]; cm α 22 19 6 0 8 7 . . . . . 0 0 1 − +0 − +1 − bin BAT f EW C 0.9 2.0 1.20 and the unabsorbed X-ray 50 11 11 10 15 . . . . − 0 0 obs 10 +0 − +0 − bin XRT ············ L Γ apec C 2.39 2.64 log 09 14 12 10 . . . 0 0 57 − 13 obs 2 BI ]; (4) equatorial hydrogen column density +0 − − +203 − +31 − AGN 2 L C − 30 A 126 log 1.08 1.20 cm 2 22 13 15 11 15 14 22 19 − ...... 5 0 0 0 0 . FI obs 0 +0 − − +0 − +0 − AGN L C Γ 1.03 1.20 1.65 1.71 log 2 1 9 . . − 6 5 . (continued) +2 − (f) bin 0 pn ··· ··· L C 80 84.1 log 2 5 5 . Table 5 12 08 13 2 06 . − . . . . . 5 0 11 0 . +4 ]; (9–10) power-law photon index of the XRB and scattered components, and apec 0 +0 − +9 − +0 − σ i 1 ACIS L − C s 10.0 0.94 24.7 0.96 log 2 ]; (27–29) logarithmic observed luminosities in the 0.5–2 keV, 2–10 keV, and 10– 1 − components in [keV]; (15–20) instrumental cross normalizations of Chandra/ACIS, − 50 0 cm 3 9 . 9 . . − . 1 1 3 3 apec obs 10 +2 − − Equ H +24 − ··· ]; (25–26) logarithmic luminosities of the components of 11.33 40.79 40.89 41.16 41.10 42.43 1426 186.7/1.13 [ 11.35 40.84 41.03 41.25 41.19 42.26 2520 164.1/1.04 [ kT F 2 N 4.9 − − 9.5 − keV log 4 cm − statistics, and the reduced one divided by degrees of freedom. The mark (f) means a fixed value. 1 12 11 10 2 . . − 0 − 2 χ obs 2 − +0 ]. The fluxes and luminosities are corrected for Galactic absorption; (30) EW of the Fe-K Host H ··· ··· ······ F 1 12.67 12.43 kT N − − − log 0.68 1 2 . 4 . 05 17 03 42 ]; (5–6) torus angular width and inclination in [degree]. When these values are not well constrained, we fix − . . . . 7 2 5 0 0 1 . 280 − +13 obs − 0 +0 − +0 − LOS +1660 − H F 12.62 12.37 kT (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) N cm − − 0.88 1.09 log 24 ]; (12–14) temperatures of the 2 —Columns: (1) object name; (2) line-of-sight hydrogen column density measured with NuSTAR in [10 − error is estimated by40,000; linking (3) the hydrogen torus column density parameters of and the using host a galaxy Markov of Chain the Monte target Carlo in (MCMC) [10 chain with a length of (31) value of CashThe [C] results or of UGCspectra 2608, with NGC XCLUMPY 5135 in ( Yamada et the al. same2020 ), manner. and NGC 7469 ( Ogawa et al. 2021 ) are obtained by analyzing the 50 keV bands in [erg s cm emission in the 0.5–2 keV band in [erg s XMM-Newton/pn, Suzaku/XIS-FI, XIS-BI, Swift/XRT, andXMM-Newton, BAT, respectively; Suzaku, (21) and time10–50 variability Swift/BAT constant keV observations; of bands (22–24) the Chandra, in logarithmic [erg observed s fluxes in the 0.5–2 keV, 2–10 keV, and in [10 the parameters asnormalization described at 1 in keV Section the in [10 fraction4.2.1 ; relative to (7–8)in the power-law transmitted the photon component epochs at index of 1 of keV the in the Chandra [%]; AGN-transmitted (C), (11) component, time XMM-Newton variable and (X), line-of-sight Suzaku its hydrogen column (S), densities Swift/XRT (XRT) and BAT (B) observations in [10 For NGC 235, the cross normalization is set to unity for the Swift/BAT as the calibration reference. Note † (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) Object NGC 5135NGC 7130 670 413.3 26 Yamada et al. ) ν 11 . 0 FI (C/C − ··· ··· ··· ··· C 2 ν χ 1.20 / 2 χ 04 07 09 04 07 10 . . . . . 0 0 − obs 2 pn +0 +0 − − +0 (f) L 1 C log 0.80 0.96 1.12 2 07 08 11 02 − . . . . 5 0 0 . obs 0 +0 − +0 − (f) (f) ············································· ··············· MOS 1 1 L C 0.98 1.18 log 2 03 04 − . . 5 0 . bin 0 − +0 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) ACIS L 1 1 1 1 1 1 1 1 1 1 40.20 40.20 40.45 36.9/0.84 [C] 40.51 40.51 40.89 63.1/0.73 [C] 0.83 log 2 02 12 04 20 13 17 14 05 38 02 08 37 04 39 19 13 11 37 − ...... 5 0 0 0 0 0 0 0 0 0 . apec 0 +0 − +0 − +0 − +0 − +0 − +0 − +0 − +0 − +0 − ··· ··· kT C L 0.79 0.84 0.38 0.74 0.56 0.83 0.97 0.97 0.68 log continued Stage-B Stage-A 6 10 7 . . − 0 obs 2 cut +0 − ··· ··· ··· ··· ··· ··· ········· ······ ··· F 12.90 40.51 40.69 40.91 40.90 1102.3/0.96 [C] 13.0912.99 40.48 39.64 40.42 40.75 40.19 40.48 40.30 2206.1/1.07 [C] 40.58 1820.6/0.9213.93 [C] 13.11 39.7213.29 40.4413.63 39.92 40.37 40.1313.79 40.82 40.29 40.97 40.46 40.48 68.9/0.78 [C] 41.11 40.72 135.2/0.78 [C] 40.77 40.04 131.1/0.80 [C] 40.62 40.29 56.6/0.81 [C] 13.29 14.11 39.5113.70 39.47 38.47 39.79 39.66 39.06 397.4/0.94 [C] 39.16 39.44 852.6/1.02 [C] E Table 6 4.7 − − − − − − − − − − − log 2 0 9 7 5 5 9 7 0 1 0 . . . . . 4 0 7 6 0 8 . . . . . 7 2 6 0 5 9 − ...... 3 0 3 3 3 5 1 1 1 2 2 0 . obs +2 − +3 − +4 − +3 − +1 − 0 bin +1 − +2 − +1 − +3 − +2 − +0 − F 12.90 12.81 13.27 14.10 13.25 13.34 13.89 13.45 13.98 13.98 13.67 A 2.3 6.0 2.3 4.4 9.8 3.7 35.0 18.7 11.6 41.6 19.0 log 11 02 16 13 20 02 01 34 15 10 81 19 31 47 ...... 0 0 0 0 0 (f) (f) +0 +0 +0 +0 +0 − +0 − +0 − +0 − +0 − bin XRT · · · − Γ 1.8 1.8 C 1.50 1.50 1.50 1.50 1.77 1.52 1.66 1.63 1.70 ) FI . Summary of the X-ray Results for Starburst-dominant or Hard X-ray Undetected Sources BI Host C H · · · · · · − · · ·· · · · · · · · − · − · · ·· · · · · ·· · · · · − ·· · · · · − ·· · · · · − · · · − · − · · · · · · − ··· ··· ··· ··· ··· ··· ··· ··· ··· ··· ··· · · · · · · − C (11) (12) (13) (14) (15) (16) (17) (18) (19) N (= Table 6 Object (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) NGC 838 NGC 839 MCG+08-18-013 MCG–01-26-013 NGC 3110 NGC 4418 MCG–02-01-052 MCG–02-01-051 NGC 232 ESO 440-58 MCG–05-29-017 27 ] ] ) 2 2 ν χ χ 08 . 0 FI (C/C − ··· ··· ··· ··· ··· ··· C 2 ν χ 1.20 / 2 χ 03 05 04 10 02 04 03 28 05 11 10 ...... 0 0 0 0 0 − obs 2 pn +0 − − +0 − − +0 − +0 +0 (f) (ref) L 1 C 1 log 0.93 0.98 0.82 1.03 1.03 2 19 11 17 12 − . . . . 5 0 0 . obs 0 +0 − +0 − (f) (f) (f) (f) ·················· ········· ········· MOS 1 1 1 1 L C 1.03 0.95 log 2 04 05 16 04 04 01 − ...... 5 0 0 0 . bin 0 +0 − − − +0 +0 ············ ······ (ref) (ref) (ref) (ref) (ref) (ref) ACIS L 1 1 1 1 1 1 40.19 40.19 40.16 534.1/1.02 [C] 0.80 1.20 1.16 1.19 log 03 03 . . 0 +0 − 2 12 02 17 19 11 19 03 07 11 09 10 02 22 14 03 63 06 18 42 22 − ...... 5 0 0 0 0 0 0 0 0 0 0 . apec 0 +0 − +0 − +0 − +0 − +0 − +0 − +0 − +0 − +0 − +0 − /0.98 ··· kT C L 05 12 . . 0 0.94 0.79 0.55 0.82 0.80 0.33 0.94 0.94 0.28 0.27 log +0 − 0.37 continued (continued) 1 7 5 . 9 Stage-C Stage-D . 5 7 10 . 4 8 . . . . . 2 4 − 1 0 obs +4 − 2 +11 − cut +3 − +0 − ········· ··· ··· ··· ··· ··· ··· F 13.03 40.93 41.17 41.36 41.42 1674.3/0.90 [C] 13.28 40.74 40.96 41.17 41.36 1627.5/0.93 [C] 13.0112.69 40.3014.28 40.91 40.84 40.08 40.95 41.09 40.98 41.31 39.6113.78 446.9/1.12 [C] 41.28 40.21 526.6/1.1312.35 [ 39.84 40.41 63.0/0.90 [C] 41.2713.79 40.45 40.73 40.98 40.76 40.64 41.22 52.6/0.75 [C] 40.95 41.10 763.5/1.20 [ 41.26 41.33 418.8/0.89 [C] 13.14 40.39 40.06 40.5613.91 40.26 104.4/1.03 [C] 40.24 40.16 40.50 40.55 23.0/0.77 [C] 13.76 13.92 39.33 39.42 39.68 39.81 226.9/0.85 [C] E Table 6 6.6 8.1 − − − − − − − − − − − − Table 6 12.2 log 16.1 1 7 2 . . 6 9 2 0 1 5 3 3 1 1 . . . . . 6 3 0 4 9 0 . . . . . 7 0 3 3 5 6 − ...... 13 6 4 3 2 1 5 1 1 2 1 0 1 . +19 − obs +7 − +8 − +3 − +2 − +1 − 0 bin +1 − +1 − +1 − +2 − +1 − +1 − F 13.47 12.65 13.09 12.07 13.85 13.03 13.91 13.70 12.84 13.97 13.72 14.06 A 8.9 4.9 1.5 5.1 2.2 2.4 − 21.2 39.2 70.5 26.9 10.1 log 235.8 33 12 22 75 12 01 52 03 05 36 12 22 ...... 0 0 0 (f) (f) (f) +0 +0 +0 +0 +0 +0 +0 − +0 − +0 − (f) bin XRT · · · − 1 Γ 1.8 1.8 1.8 C 1.50 1.50 1.50 1.50 1.50 1.50 2.14 2.06 1.75 14 03 04 . . . 0 0 BI − +0 − Host H · · · · · · − · · · · · · − · · · · · ·· · · − · · · − · · · · · ·· · · − · · · − · · · · · · − ··· ··· ··· ··· ··· ··· ··· ··· ··· ··· ··· ··· · · · · · · − · · · · · · − · · · · · · − C (11) (12) (13) (14) (15) (16) (17) (18) (19) N 1.20 Object (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) IC 4518B NGC 6285 NGC 6907 ESO 350-38 IC 1623A NGC 4922S II Zw 096 IRAS F20550+1655 SE ESO 374-IG032 NGC 3256IRAS F10565+2448 IRAS F12112+0305 0.18 28 Yamada et al. ) ν FI (C/C ··· ··· ··· C 2 2 ν χ χ and / 2 χ apec 16 11 09 19 09 12 10 ...... ]; (5) cutoff 0 0 0 − 1 obs 2 pn +0 − − +0 − +0 − L s C 2 ]; (3–4) power-law log 1.00 1.02 0.95 − 2 means that it is set − cm 2 10 − . cm 1 5 0 . (ref) − obs 0 − (f) (f) 22 ········· ········· MOS 1 1 L C keV 1.20 log 6 − 2 08 09 08 10 − . . . . 5 0 0 . bin 0 − +0 +0 − (ref) (ref) (ref) ACIS L 1 1 1 40.75 40.75 40.38 39.4/0.90 [C] 40.97 40.97 41.36 41.3/0.78 [C] 1.04 0.92 log 2 11 23 23 05 10 10 33 04 − ...... 5 0 0 0 0 . apec 0 +0 − +0 − +0 − +0 − ··· ··· kT C L 1.03 0.58 1.01 0.94 log (continued) ]; (17–18) logarithmic observed luminosities in the 0.5–2 keV and 1 − Stage-N 4 10 4 ]; (15–16) logarithmic luminosities of the components of . . − 2 1 obs 2 cut − +2 − ·················· ··· ··· ··· ······ F 14.0413.82 40.8513.21 41.58 40.81 41.1413.52 41.13 41.2012.83 40.83 41.74 41.08 399.3/0.90 [C] 41.45 41.44 40.15 47.5/0.70 [C] 41.43 1183.5/0.88 40.87 [C] 40.95 41.04 1626.9/1.02 [C] 13.68 E cm 7.6 − − − − − − Table 6 log 1 − 2 5 9 7 0 1 . 7 . . 9 8 4 . . 0 2 6 − ...... 1 5 5 components in [keV]; (7–12) instrumental cross normalizations of Chandra/ACIS, 9 0 2 1 . obs +2 − +6 − 0 +11 − bin +1 − +3 − +1 − F 13.73 13.20 12.92 13.52 13.15 14.06 A 4.4 4.6 4.2 − apec 13.6 53.2 32.5 log 25 12 52 33 06 23 11 17 ...... 0 0 0 (f) +0 +0 +0 − +0 − +0 − bin XRT (ref) Γ 1 1.8 C ]. The fluxes and luminosities are corrected for Galactic absorption; (19) value of Cash [C] or 1.50 1.50 2.07 1.64 2.67 1 − BI Host H · · · · · ·· · · − · · · − · · · · · · − · · · · · · − ··· ··· ··· ··· ··· ··· ··· · · · · · · − C (11) (12) (13) (14) (15) (16) (17) (18) (19) N —Columns: (1) object name; (2) hydrogen column density of the host galaxy of the target in [10 photon index of the XRB and scattered components, and its normalization at 1 keV in [10 2–10 keV bands in [erg s to unity as thein calibration the reference 0.5–2 whenunabsorbed the keV X-ray NuSTAR and emission spectra in 2–10 have the too keV 0.5–2 poor bands keV band statistics; instatistics, in (13–14) [erg and [erg logarithmic s the s observed reduced fluxes one divided by degrees of freedom. The mark (f) means a fixed value. energy in [keV]; (6) temperaturesXMM-Newton/MOS, of pn, the Suzaku/XIS-FI, XIS-BI, Swift/XRT, and BAT, respectively. The mark 1 Note Object (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) IRAS F14378–3651 IRAS F15250+3608 IRAS F19297–0406 ESO 286-19 NGC 5104 IRAS F18293–3413 29

Table 7. Additional Emission Lines in X-ray Spectra 5.1. X-ray Color and AGN Classification The NuSTAR band ratio (BRNu) is useful to roughly Object ASi(1.86 keV) EFe AFe constrain the presence of an AGN and its classification −6 −6 (10 ) (keV) (10 ) even for hard X-ray undetected sources. In fact, the two (5) (6) (7) (8) starburst-dominant sources have much smaller band ra- Stage-A, N (AGNs) tios than those of the AGNs. Lansbury et al.(2017) ab +0.27 MCG–03-34-064 1.67−0.27 ······ report that CT AGNs can be efficiently selected by ap- NGC 7130 1.55+0.66 ······ −0.65 plying a cut at BRNu > 1.7 in the 40-month NuSTAR NGC 7674 ··· 6.97(f) 1.96+0.83 −0.83 serendipitous survey. Stage-C, D (AGNs) +0.23 Figure2 plots the NuSTAR band ratio against red- UGC 5101 0.38−0.23 ······ +1.17 shift for all objects. The curves are calculated based on NGC 3690 West 2.44−1.18 ······ +0.36 +0.02 +0.27 IRAS 13120–5453 1.02−0.35 6.67−0.03 1.04−0.26 the AGN model by assuming a photon index of ΓAGN Arp 220W 0.34+0.17 6.67+0.02 1.31+0.24 −0.17 −0.02 −0.24 (= Γbin) = 1.8, an unabsorbed X-ray emission fraction Stage-D (starburst-dominant or hard X-ray undetected sources) ◦ of fbin = 1%, a torus angular width of σ = 20 , and an NGC 3256b 9.08+0.99 6.66+0.05 1.07+0.28 −0.91 −0.04 −0.27 inclination of i = 60◦ (for N LoS = 1022 cm−2) or i = 80◦ ESO 286-19c ··· 6.56+0.12 0.45+0.41 H −0.32 −0.31 LoS 24 −2 Nu (for NH ≥ 10 cm ). As noticed, BR & 0.5, cor- Note—Columns: (1) object name; (2) normalization of the Si Kα responding to N LoS > 1022 cm−2 (black dotted curve), line at 1.86 keV; (3–4) rest-frame central energy and normalization H of the highly ionized Fe Kα line. may be used as a selection criterion to identify AGNs in a +1.25 −6 local U/LIRGs, mostly obscured ones (37/40 AGNs), by The Ni Kα line at 7.48 keV (ANi = 3.06 ×10 ) is added. −1.23 discriminating from starburst-dominant galaxies. This b −6 The Mg XI Kα line at 1.342 keV (AMg = 2.07 ± 0.39 ×10 for implies that there may be a few more AGN candidates MGC-03-34-064 and 7.39+2.19 ×10−6 for NGC 3256) is added. −2.11 even in the hard X-ray undetected (S/N < 3σ) sources, c +1.66 −6 Nu The O VIII Kα line at 0.654 keV (AO = 3.29−1.52 ×10 ) is added. which show BR ∼0.0–1.0 within the uncertainties. We note that the relation of the NuSTAR band ratio to AGN type (CT or not) differs with merger stage. Most of CT AGNs in stage-A, B, and N systems (5/7 CT AGNs, including the dual AGN in Mrk 266) have the band ratios of &1.6, well consistent with the threshold 5. X-RAY AND MULTIWAVELENGTH RESULTS value of 1.7 for normal AGNs (Lansbury et al. 2017). By Out of our sample (57 U/LIRG systems consisting of contrast, the CT AGNs in stage-C and stage-D mergers 84 individual galaxies observed with NuSTAR and/or have smaller band ratios of ≈0.5–1.2. This is because (1) 24.5 −2 Swift/BAT), we have carried out a systematic spectral some of them are heavily CT (NH & 10 cm ) where analysis for 59 galaxies by adopting the AGN model the transmitted AGN components become fainter, and or the starburst-dominant model. For the other 10 (2) the unabsorbed emission fractions are large (fbin ∼ galaxies mentioned in Section 2.5, we refer to the lit- 10%) most probably due to the enhanced contribution erature for the spectral analysis results. Among these from the XRBs associated with the intense starbursts 69 galaxies, there are 40 hard X-ray detected AGNs (e.g., Mineo et al. 2012). Nu (Section 4.2.1). According to their hydrogen column The hard X-ray undetected sources show small BR densities, we categorize them as two unobscured AGNs values (∼0.0–1.0). This suggests that many of them may LoS 22 −2 LoS 22 be starburst-dominant (see also Section 6.2), although (NH < 10 cm ), 21 obscured AGNs (NH = 10 – 24 −2 LoS 24 −2 we cannot exclude the presence of AGNs in these ob- 10 cm ), 16 CT AGNs (NH ≥ 10 cm ), and one jet-dominant AGN (NGC 1275). jects. The possible AGNs in stage-A, B, and N systems In this section, we discuss the X-ray and multiwave- are not likely to be CT by considering the threshold length properties of our sample as follows: Section 5.1 value of 1.7. Whereas, those in stage-C and D merg- describes the X-ray color and AGN classification, Sec- ers may well be CT AGNs within the uncertainties in Nu tion 5.2 the fractions of CT AGNs for different merger BR . These implications are consistent with a larger stages, Section 5.3 the properties of AGNs and host fraction of CT AGNs in late mergers than in early ones galaxies, in particular the bolometric AGN luminosities for the hard X-ray detected AGNs as reported by Ricci (Section 5.3.1), the features of multiphase outflows (Sec- et al.(2017a) and shown in the next section. tion 5.3.2), the black hole masses (Section 5.3.3), and It is also noticeable that the fractions of merger stages the Eddington ratios and bolometric correction factors among the hard X-ray detected AGNs are different be- (Section 5.3.4). tween the low and high redshift ranges. At z . 0.03, 30 Yamada et al.

5 Stage-A(Early) Stage-B(Early) Stage-C(Late) 4 Stage-D(Late) Stage-N Unobscured AGN 3 Obscured AGN logNH=24 CT AGN Dual AGN Jet-dominant AGN 2 non-AGN(SB) HX nondet.

logN =24.5 1 H

logNH=22 0 NuSTAR Band Ratio (8-24keV/3-8keV) 0.00 0.02 0.04 0.06 0.08 0.10 Redshift (z)

Figure 2. NuSTAR band ratio vs. redshift for the unobscured AGNs, obscured AGNs, CT AGNs, dual-AGNs (Mrk 266 and NGC 6240), jet-dominant AGN (NGC 1275), 8–24 keV detected but starburst-dominant sources, and 8–24 keV undetected sources. These marks are color coded by merger stage. The black dotted, dashed and solid curves show the band ratio assuming LoS 22 24 24.5 −2 an unobserved soft X-ray fraction of fbin = 1% and NH = 10 , 10 , and 10 cm , respectively.

AGNs are detected in all merger stages, whereas most It is expected that the central SMBHs rapidly grow in of AGNs at z & 0.03 are obscured ones in stage-C and these heavily obscured environments. stage-D mergers (consisting of six obscured and three Several observational approaches to prove heavy ob- CT AGNs). This may be subject to a selection bias that scuration in galaxy mergers have been attempted. Re- only luminous (but not CT) AGNs can be detectable cent observations in the submillimeter band report the with NuSTAR at higher redshifts. We have to bear it in evidence for compact obscuring material with NH > mind when discussing statistical properties of our sam- 1024 cm−2 around the nuclei on the tens-pc scales in ple. ULIRGs, known as compact obscuring nuclei (CON; Sakamoto et al. 2010; Costagliola et al. 2013; Aalto et al. 2015, 2019; Scoville et al. 2015; Falstad et al. 2021). In 5.2. Fraction of CT AGNs the mid-IR band, Yamada et al.(2019) suggest that the It is theoretically predicted that merger-driven dy- AGNs in late mergers are deeply buried in geometrically namics may trigger heavy obscuration from the galactic thick tori (e.g., Ueda et al. 2007, 2015; Imanishi et al. scales to nuclear scales around the SMBH (e.g., Barnes 2008), by using the luminosity ratio between the nuclear & Hernquist 1991; Mihos & Hernquist 1996; Springel & 12 µm (Asmus et al. 2014) and [O IV] 25.89 µm emis- Hernquist 2003; Di Matteo et al. 2005; Springel et al. sion, which originate from dusty tori and narrow line 2005; Hopkins et al. 2006; Angl´es-Alc´azaret al. 2017). regions (NLRs), respectively. In addition, by analyzing If outflows caused by the AGN do not significantly affect the X-ray spectra of 30 interacting U/LIRGs including the gas distribution, the nucleus should be surrounded 25 AGNs, Ricci et al.(2017a) study the relation between roughly spherically by gas and dust falling from random AGN obscuration and galaxy mergers. They find that directions. The numerical simulations of mergers on a all AGNs in late mergers have large column densities 23 −2 scale of &48 pc (Blecha et al. 2018) suggest that the of NH > 10 cm toward the nuclei. The estimated peak column densities reach the CT regime, and even fraction of CT AGNs in late mergers is higher (fCT = the average ones become ∼3 × 1023 cm−2 during merg- +12 +13 65−13%) than in early-merger stage (fCT = 35−12%) ers. Recent higher resolution simulations by Kawaguchi and in local hard X-ray selected AGN (fCT = 27 ± 4%; et al.(2020) also show the most luminous phase of the Burlon et al. 2011; Ricci et al. 2015). This is in line with 24 −2 AGN is obscured by gas with NH & 10 cm for an the presence of compact CT material in late mergers. 23 −2 edge-on view and NH & 10 cm for a face-on view. 31

In this work, we obtain thus-far the largest sample consisting of 39 hard X-ray detected AGNs selected from 1025 the GOALS sample (except for the jet-dominant AGN in NGC 1275). Figure3 represents the relation be- 1024 tween galaxy separation and line-of-sight column den- ] sity, color-coded by the merger stages. In our sam- 2 1023 ple, the fractions of CT AGNs are found to be fCT = m c [

50 ± 11% (9/18 sources) in the late mergers and fCT = S 22 Stage-A(Early) +12 o 10 L 22−9 % (3/15 sources) in the early mergers. Here, the H Stage-B(Early) N values and uncertainties represent the 50th and 16th– Stage-C(Late) Stage-D(Late) 1021 84th quantiles of a binomial distribution, respectively, Stage-N calculated with the beta function (Cameron 2011). The obtained values are a little smaller than the results of 1020 18 0 20 40 60 80 100 Ricci et al.(2017a). Separation [kpc] We find that the absorption column densities of NGC 7674 and NGC 7682 are smaller than those reported Figure 3. Line-of-sight hydrogen column density vs. galaxy in previous works, mainly because of the difference of separation. The blue circles, green triangles, orange dia- monds, red , and purple triangles denote the AGNs in the X-ray spectral data utilized (see AppendixB). The stage-A, B (early mergers), C, D (late mergers), and stage-N slightly smaller column density of UGC 5101 (NH ∼ (nonmergers) U/LIRGs, respectively. Single nuclei in merg- 9.6 × 1023 cm−2) than the one in the previous NuSTAR ing (stage-D) and nonmerging (stage-N) sources are plotted study (∼1.3 ×1024 cm−2; Oda et al. 2017) also works on the left and right ends, respectively. The black dotted LoS 22 −2 24 −2 to decrease the fraction of CT AGNs. Nevertheless, our and dashed lines denote NH = 10 cm and 10 cm , results support the earlier result that most AGNs in late respectively. The unobscured AGNs (NGC 7469 and NGC LoS 20 −2 23 −2 7679) are assigned upper limits of NH = 10 cm . mergers are obscured with NH & 10 cm , which is consistent with the numerical simulations. To avoid the possible selection bias mentioned in Sec- AGNs in UGC 2608 and NGC 5135 are a normal AGN tion 5.1, we also calculate the CT AGN fraction by using population seen close to edge-on through a large line- only AGNs at z < 0.03, which would give a more likely of-sight column density. We note that this CT-AGN +15 estimate of the intrinsic value. In this case, the fraction fraction in stage-N sources (fCT =64−18%; 4/6 sources) 24 −2 of AGNs with NH > 10 cm in late-merger stage is is highly uncertain under the small statistics and may +14 be subject to the sample selection bias as mentioned fCT = 64−15% (6/9 sources), where the torus opening angle of the CT materials is calculated to be 50 ± 11 de- in Section 2.4. Therefore, these results for AGNs at grees assuming the uniform-density spherical geometry z < 0.03 support the scenario that AGNs in late merg- with bipolar cone holes. We obtain a similar value, fCT ers are heavily obscured by surrounding CT material, +11 while those in early mergers and nonmergers are not = 80−16% (6/7 sources), by using sources at projected separations of 0.3–5.6 kpc.19 The fraction of CT AGNs deeply buried, as reported by recent works (e.g., Ricci +12 et al. 2017a; Yamada et al. 2019). in early mergers (fCT = 24−10%; 3/14 sources) coin- cides with that obtained from Swift/BAT AGNs (27 ± 4%; Ricci et al. 2015) within the uncertainty. Among the 5.3. Properties of AGNs and Host Galaxies from the stage-N sources, four out of six AGNs are CT AGNs; the X-ray and Multiwavelength Observations two CT AGNs in NGC 1068 and NGC 7130 may be af- 5.3.1. Bolometric AGN Luminosities fected by past mergers (Davies et al. 2014; Tanaka et al. The bolometric luminosity is one of the most impor- 2017). By analyzing the X-ray spectra with XCLUMPY, tant quantity to characterize the AGN activity. It can Yamada et al.(2020) indicate that the other two CT be calculated from the absorption-corrected 2–10 keV luminosity with a bolometric correction factor, κbol,X = 18 The fraction of the CT AGNs in late mergers with a separation Lbol,AGN/L2−10. In many works, κbol,X = 20 or 30 is +13 of 0.4–10.8 kpc is 53−12% (7/13 sources), which is also smaller adopted as a typical value (e.g., Ricci et al. 2017b). An- than the peaked value (77+13%) reported by Ricci et al.(2017a). −17 alyzing the optical, UV, to X-ray spectral energy distri- 19 If we exclude the AGNs for which we assume fscat = 10%, these +14 butions (SEDs) of nearby AGNs, Vasudevan & Fabian fractions are calculated to be 68−17% (5/7 sources) in late merg- +13 (2007) show that κbol,X actually depends on the Ed- ers and 77−17% (5/6 sources) among sources with 0.3–5.6 kpc separations. dington ratio (λEdd ≡ Lbol,AGN/LEdd, where LEdd = 38 1.26×10 MBH/M is the Eddington limit for a black- 32 Yamada et al. hole mass of MBH): κbol,X ≈ 15–30 for λEdd . 0.1, the 6.2 µm polycyclic aromatic hydrocarbons (PAH; see κbol,X ≈ 20–70 for λEdd ∼ 0.1–0.2, and κbol,X ≈ 70– also Armus et al. 2007), the S30/S15 dust continuum ra- 150 for λEdd & 0.2. However, Teng et al.(2015) report tio, and the Laurent diagram (Laurent et al. 2000). We that AGNs in some ULIRGs have much higher bolo- adopt the averaged bolometric AGN fractions based on metric corrections than these values obtained for nor- all diagnostics.20 3 mal AGNs, such as Mrk 231 (κbol,X ∼ 3 × 10 ) and The third and fourth methodologies are to directly 4 IRAS F08572+3915 (κbol,X & 10 ). Thus, it is impor- estimate the bolometric AGN luminosities from broad- tant to estimate the bolometric luminosities from other band SED decomposition and Spitzer/IRS spectral fit- wavelength observations, in particular, those in the IR ting, respectively. Shangguan et al.(2019) present a de- band (e.g., Veilleux et al. 2009a; D´ıaz-Santos et al. 2017; tailed study of the IR ∼1–500 µm SEDs of 193 U/LIRGs Shangguan et al. 2019; Toba et al. 2021a), independently in the GOALS sample. The entire sample has been of X-ray measurements. uniformly observed with the Two Micron All Sky Sur- We summarize four major methodologies to estimate vey (2MASS; Skrutskie et al. 2006), Wide-field Infrared the bolometric AGN luminosity of an U/LIRG from the Survey Explorer (WISE; Wright et al. 2010), and Her- IR spectroscopic or photometric data. The first one is schel Space Observatory (Pilbratt et al. 2010). They to use the [O IV] 25.89 µm luminosity. Its ratio to the fit the SEDs by considering the torus component for bolometric AGN luminosity is obtained for local 12 µm- which they adopt a new version of the CAT3D (H¨onig selected Seyfert galaxies (12MGS; Rush et al. 1993) & Kishimoto 2017) torus model. This model takes into by performing broadband SED decomposition (Grup- account the different sublimation temperatures for sili- pioni et al. 2016). This can be widely applied for the cate and graphite dust (producing more emission from GOALS objects because their [O IV] fluxes are system- hot dust at the inner edge of the torus than in the case atically measured from the Spitzer/IRS spectra (e.g., of a single sublimation temperature) and a com- Inami et al. 2013). The line emission comes from AGN- ponent, which allows greater flexibility to accommodate excited ions in the NLR, whose luminosity should be the diversity of IR SEDs of quasars (Zhuang et al. 2018). proportional to the AGN luminosity for a given geome- The SED fits are conducted without the wind compo- try of the NLR. Since the [O IV] line is far more robust nent, whereas the Spitzer/IRS spectral fits for 61 ob- to extinction and is less contaminated by jects are performed with an additional wind component. activity than the optical [O III]λ5007 line, it gives a more Assuming the bolometric-to-IR luminosity correction of reliable estimate of the bolometric AGN luminosity for the AGN emission to be 3.0 (e.g., Delvecchio et al. 2014), heavily obscured objects with high star formation rates we obtain the bolometric AGN luminosities from the IR like U/LIRGs. We note that the [O IV] 25.89 µm-to- 8–1000 µm luminosity of the torus component derived bolometric luminosity ratio becomes smaller for deeply from the SED fitting and Spitzer/IRS spectral analy- buried AGNs in ULIRGs where the NLR is less devel- sis. For some U/LIRGs, we also refer to the bolometric oped compared with normal AGNs (e.g., Imanishi et al. AGN luminosities obtained from Spitzer/IRS spectral 2008; Yamada et al. 2019). analysis by Alonso-Herrero et al.(2012). The second one is to use the fractional AGN contribu- We list the bolometric AGN luminosities for the tion to the bolometric “total” luminosity that includes hard X-ray detected sources in Table8 and those for the AGN and starburst components. The total bolo- starburst-dominant or hard X-ray undetected sources, metric luminosity of an U/LIRG can be calculated as most of which should be considered as upper limits, in 1.15 times the IR luminosity in the 8–1000 µm band Table9. By excluding the upper limits from the [O IV] (LIR) (e.g., Kim & Sanders 1998; Veilleux et al. 2009a; 25.89 µm luminosities, the bolometric AGN luminosities Teng et al. 2015). Table1 lists LIR for each U/LIRG obtained from the four methods are found to be approx- system; for the interacting systems, we also show iden- imately the same for each object typically with a scatter tification by Inami et al.(2013) which galaxy (or both) of ∼0.27 dex (see AppendixA). Thus, we adopt these in the system mainly contributes to the observed IR lu- averaged values as the best-estimates of the bolomet- minosity on the basis of the detection with Spitzer/IRS. D´ıaz-Santos et al.(2017) calculate the fractional AGN 20 Yamada et al.(2019) investigate the difference between the contribution to the bolometric total luminosity for each mean AGN fractions calculated by including and excluding the system in the GOALS sample with the IRS observations [Ne V]14.3/[Ne II]12.8 and [O IV]25.9/[Ne II]12.8 line flux ratios (see also Veilleux et al. 2009a; Petric et al. 2011). They because these may not good indicators in buried AGNs. The av- eraged value of the three diagnostics is slightly larger than that employ up to five methods: the [Ne V] /[Ne II] 14.3 12.8 from the five methods by a factor of 1.1–1.7. and [O IV]25.9/[Ne II]12.8 line flux ratios, the EW of 33 ric AGN luminosities. In Tables8 and9, we also list 5.3.3. Black Hole Masses in U/LIRGs the star formation rate (SFR)21 obtained with SED de- In Table 10, we list black hole masses estimated from composition and Spitzer/IRS spectral analysis (Pereira- four methods for the hard X-ray detected AGNs. Two Santaella et al. 2015; Gruppioni et al. 2016; Shangguan dynamical estimates of black hole masses are avail- et al. 2019).22 able, one from the relation with stellar mass for local AGNs (Reines & Volonteri 2015) and the other from 5.3.2. Features of Multiphase Outflows that with stellar velocity dispersion (M–σ∗ relation, Recent multiwavelength observations have detected G¨ultekinet al. 2009). The stellar masses are mainly ob- signals of outflows on the various scales in U/LIRGs tained from SED decomposition (e.g., Pereira-Santaella (Fiore et al. 2017; Fluetsch et al. 2021). Ultrafast out- et al. 2015; Shangguan et al. 2019). The stellar velocity flow (UFO), an extremely fast (∼0.1–0.3c) and highly- dispersions are taken from the literature (e.g., Dasyra ionized wind emanating from a close vicinity (∼10−2 pc) et al. 2006a,b). We also collect the photometric black- of an SMBH, is seen as X-ray blueshifted absorption hole mass estimates (e.g., Winter et al. 2009; Veilleux lines in some U/LIRGs (e.g., Tombesi et al. 2015; Fer- et al. 2009b; Haan et al. 2011) using the relation with uglio et al. 2015; Mizumoto et al. 2019). On kpc scales, H-band bulge luminosity LH,bulge (Marconi & Hunt −1 fast (an order of 1000 km s ) and massive outflow of 2003), given as logMBH = 8.19(±0.07)+1.16(±0.12) × ionized gas has been discovered by deep optical/near- (logLH,bulge − 10.8). Finally, we list black-hole mass IR spectroscopy mainly from field observations estimates from other various methods: the flux den- (IFU; e.g., Fischer et al. 2013; Rich et al. 2015; Cortijo- sity of old stellar emission at 2 µm (Caramete & Bier- Ferrero et al. 2017a; Toba et al. 2017a; Kakkad et al. mann 2010); scaling relations from McConnell & Ma 2018; Venturi et al. 2018; Smith et al. 2019; U et al. 2019; (2013) and the central velocity dispersion of the Cal- Boettcher et al. 2020; Fluetsch et al. 2021). At the far- cium triplet absorption lines (Koss et al. 2016); the IR and millimeter/submillimeter wavelengths, molecu- reverberation mapping study (Bentz & Katz 2015); a lar outflow, a cold gas wind with a size of ∼400 pc and three-dimensional plane connecting log(MBH) to a lin- a velocity of ∼500 km s−1, is observed in many U/LIRGs ear combination of logarithmic velocity dispersion and (e.g., Spoon et al. 2013; Veilleux et al. 2013; Cicone et al. luminosities of the NLR lines (Dasyra et al. 2011); the 2014; Gonz´alez-Alfonsoet al. 2017; Laha et al. 2018 and velocity dispersion of [O III] emission (Alonso-Herrero the references therein; Lutz et al. 2020; but see e.g., et al. 2012); an empirical relationship in Kaspi et al. Toba et al. 2017b). (2000) using the Hβ line width and optical continuum Fiore et al.(2017) find strong correlations between luminosity at rest-frame 5100 A(˚ Kawakatu et al. 2007); the ionized and molecular mass outflow rates and the and water masers (Kl¨ockner & Baan 2004; Lodato & bolometric AGN luminosity by using 94 AGNs with Bertin 2003; see also Izumi et al. 2016). The last rows massive winds at sub-pc to kpc spatial scales. They of Table 10 list the averages of the black-hole mass esti- also find that the maximum outflow velocity correlates mates derived from these methods. with the bolometric AGN luminosity. Thus, physical pa- We find that the black-holes mass measurements in rameters of outflows, such as outflow velocity (Voutflow) U/LIRGs from dynamical stellar mass and velocity dis- and mass outflow rate (M˙ outflow), provide rich informa- persion are systematically smaller by a factor of ∼4–9 tion on mass transportation between an SMBH and the (∼0.55–0.95 dex) than those from the other methods host galaxy. We summarize the properties of outflows (see bottom rows in Table 10). Veilleux et al.(2009b) collected from the literature for hard X-ray detected report this tendency in U/LIRGs, who conclude that it sources in Table8 and for starburst-dominant or hard is caused by a systematic difference in the velocity dis- X-ray undetected sources in Table9. persion between the optical (Ca II) and near-IR (CO) measurements. The photometric black-hole mass esti- mates may also have large uncertainties because of possi- 21 The SFRs are basically calculated from the IR luminosities of the ble effects from non-nuclear star formation, dust extinc- host galaxies through the Kennicutt(1998) relation (Gruppioni et al. 2016; Shangguan et al. 2019). Pereira-Santaella et al.(2015) tion, and point-spread function subtraction. Particu- obtain SFRs using a stellar emission model that considers several larly, the photometric estimates would be overestimated star bursts of different ages, and report that their estimates are in smaller mass hosts with smaller black-hole masses (see also in good agreement with the Kennicutt(1998) relation. Veilleux et al. 2009b). These systematic differences seem 22 We also refer to the SFRs obtained from the total (AGN and starburst) IR luminosities (Howell et al. 2010). Thus, we treat not to be correlated with either the bolometric AGN lu- the values for the hard X-ray detected AGNs (i.e., NGC 235 and minosities or Eddington ratios, as noted in AppendixA. Mrk 266B/Mrk 266A) as upper limits (listed in Table8). To minimize the selection effects of these measurements, 34 Yamada et al.

44.5 46.5 Stage-A(Early) Stage-A(Early) 44.0 Stage-B(Early) 46.0 Stage-B(Early) Stage-C(Late) Stage-C(Late) 43.5 Stage-D(Late) 45.5 Stage-D(Late) Stage-N Stage-N N

0 43.0 45.0 G 1 A , ) l R o 2 I ( 42.5 b 44.5 L L g g o l o

42.0 l 44.0

41.5 43.5

41.0 43.0

40.5 42.5 0 20 40 60 80 100 0 20 40 60 80 100 Separation [kpc] Separation [kpc]

Figure 4. Left panel: absorption-corrected 2–10 keV luminosity vs. galaxy separation. Right panel: bolometric AGN luminosity based on the IR results vs. galaxy separation. Symbols and colors are the same as in Figure3.

1 1 Stage-A(Early) Stage-A(Early) Stage-B(Early) Stage-B(Early)

] 0 Stage-C(Late) 0 Stage-C(Late) 0

2 Stage-D(Late) Stage-D(Late)

= Stage-N Stage-N

X R , I l

1 , 1 o d b d k E [

g X , 2 o 2 l d d E g o

l 3 3

4 4 0 20 40 60 80 100 0 20 40 60 80 100 Separation [kpc] Separation [kpc]

(IR) Figure 5. Left panel: X-ray based Eddington ratio vs. galaxy separation, where κbol,X (= Lbol,AGN/L2−10) = 20 is assumed. Right panel: IR based Eddington ratio vs. galaxy, where the bolometric AGN luminosities based on the IR results are adopted. The black dashed line shows the Eddington limit (λEdd = 1). Symbols and colors are the same as in Figure3. we decide to adopt the averaged value of the black-hole width is fixed to 20◦ (see Section 6.1.4 for detailed dis- masses estimated from the four methods. Hence, the cussion of CT). Eddington ratios should be considered to have system- Figures4 and5 show the relation between the L2−10, atic uncertainties of ∼0.3–0.5 dex originating from those (IR) Lbol,AGN, λEdd,X and λEdd,IR with the galaxy separa- in the black-hole mass estimates. tion. From Figure4, we find that the maximum X- 5.3.4. Eddington Ratios and Bolometric Corrections ray and bolometric AGN luminosities increase with de- creasing galaxy separation. A similar tendency of X- For the hard X-ray detected AGNs, Table 11 summa- ray luminosities is found by a study of dual-AGN sys- rizes the absorption-corrected X-ray luminosities in the tems among the Swift/BAT 58-month AGNs (Koss et al. 2–10 keV and 10–50 keV bands (L and L ), the 2−10 10−50 2012). From Figure5 we find that the maximum Ed- averaged bolometric AGN luminosities from the IR re- dington ratios estimated by the IR results (λ ) in- sults (L(IR) ), the averaged black hole mass estimates Edd,IR bol,AGN crease with decreasing the separation. The peak values (M ), the Eddington ratios from the X-ray (assum- BH reach the Eddington limits. This is consistent with re- ing κ = 20) and IR results (λ and λ ), bol,X Edd,X Edd,IR cent numerical simulations (e.g., Kawaguchi et al. 2020). the bolometric corrections (κbol,X), and the torus cov- The peak of the Eddington ratios assuming κbol,X = 20 ering factors (CT) derived from the torus parameters of XCLUMPY excluding the case when the torus angular 35

Stage-A(Early) 104 Lusso+12 104 Stage-B(Early) Stage-A(Early) Stage-C(Late) Stage-B(Early) Stage-D(Late) Stage-C(Late) Stage-D(Late) 3 Stage-N 103 10 Stage-N X X , , l l o o b b 2

10 k 2 k 10

101 101

100 0 20 40 60 80 100 4 3 2 1 0 Separation [kpc] log Edd, IR

(IR) Figure 6. Left panel: bolometric-to-X-ray correction (κbol,X = Lbol,AGN/L2−10) vs. galaxy separation. Right panel: bolometric- to-X-ray correction vs. IR-based Eddington ratio. The black solid curve and gray shaded area represent the relation and its 1σ dispersion found by Lusso et al.(2012) for type-1 AGNs. The black dashed line shows a typical value of κbol,X = 20. Symbols and colors are the same as in Figure3. accrete gas via an Eddington-limited, Bondi-Hoyle like prescription. According to their results, the maximum 104 Martocchia+17 bolometric luminosities in gas-rich major mergers can be Stage-A(Early) 45.0 46.5 −1 Stage-B(Early) ∼10 –10 erg s , while those in gas-poor mergers Stage-C(Late) are ∼1043.5–1045.0 erg s−1 (see Blecha et al. 2018). Thus, Stage-D(Late) 3 10 Stage-N the bolometric AGN luminosities observed in the late 43.5 46.5 −1

X mergers of our sample, ∼10 –10 erg s , are con- , l o

b sistent with these numerical simulations. Furthermore,

k 2 10 more recent numerical simulations of galaxy mergers on a scale of 8 pc (Yutani et al. 2021) show that the bolo- metric AGN luminosities are dramatically variable by 101 two orders of magnitude in a few Myr. This long-term time variability may also explain the dispersion of AGN 6.5 7.0 7.5 8.0 8.5 9.0 9.5 luminosity in our sample. log(M ) [M ] BH Figure6 shows the bolometric correction, κbol,X, as Figure 7. Bolometric-to-X-ray correction vs. black hole a function of the galaxy separation and the Eddington mass. The black solid curve and gray shaded area represent ratio. From the left panel in Figure6, we find that the relation and its 1σ dispersion found by Martocchia et al. the bolometric corrections in the late mergers are much (2017) for WISSH quasars, PG quasars, and XMM-Newton- larger than those in the early mergers and nonmergers. COSMOS Seyfert 1s. The black dashed line shows a typical In fact, the trend of X-ray weakness has been reported value of κbol,X = 20. Symbols and colors are the same as in for AGNs with high Eddington ratios in late mergers Figure3. (e.g., Teng et al. 2015; Yamada et al. 2018) and higher- z IR-bright dust obscured galaxies (DOGs; e.g., Ricci (λEdd,X) is much smaller than that from the IR. This et al. 2017d; Vito et al. 2018; Toba et al. 2019, 2020). may imply the X-ray weakness in late-stage mergers. Using the X-ray selected sample of 929 AGNs from Whereas, some AGNs in late mergers have moderate the XMM-Newton survey in the Cosmic Evolution Sur- or small luminosities even from the IR estimates. The vey field (XMM-COSMOS; Hasinger et al. 2007), Lusso simulations of Blecha et al.(2018) indicate that the max- et al.(2012) provide the relation between bolometric imum bolometric AGN luminosity depends on the pro- correction and Eddington ratio. However, as shown in genitor galaxy parameters such as total and stellar mass the right panel of Figure6, the bolometric corrections of the galaxy, initial gas fraction in the galaxy disc, and in some of the late (particularly stage-D) mergers are bulge-to-total mass ratio. In their simulations, black significantly higher than the expected values from this holes are modeled as gravitational sink particles that relation by a factor of ∼10–100. 36 Yamada et al.

The excess of the bolometric factors in late merg- We first examine a possibility that the absorption- ers cannot be explained by possible uncertainties in the corrected X-ray luminosities might be underestimated bolometric luminosities because both of the bolometric due to time variability. Since X-ray and IR emission (IR) correction, κX,bol = Lbol,AGN/L2−10, and Eddington ra- from an AGN arise from the innermost hot corona and (IR) 38 circumnuclear regions (∼1–10 pc scale), respectively, an tio, λEdd,IR = Lbol,AGN/(1.26 ×10 MBH), are propor- tional to the bolometric luminosity. The uncertainties object could become apparently X-ray faint if it is ob- in the black hole mass measurements (∼0.3–0.5 dex, see served in a fading phase of AGN activity (e.g., Kawa- Section 5.3.3) are also too small to account for it. These muro et al. 2017; Ichikawa et al. 2019a,b; Cooke et al. facts indicate that the AGNs in late mergers are truly 2020). For example, the AGN in NGC 7674 shows a +1071 X-ray weak. large bolometric correction of κbol,X = 529−328 , al- Martocchia et al.(2017) perform a survey of the X-ray though the galaxy is assigned as a stage-A merger. The properties of 41 objects from the WISE/SDSS selected long-term X-ray light curve of NGC 7674 shows an X- hyper-luminous (WISSH) quasars at z ∼ 2–4. These IR ray flux decrease by more than one order of magnitude sources have large bolometric corrections of ∼100–1000, between 1989 and 1996 (Gandhi et al. 2017), and hence and therefore they may be similar population to our it could still be in a fading phase when the X-ray data 23 sample. They point out a possible positive correlation were taken. However, it is very unlikely that such time between bolometric correction and black hole mass, variability explains the all X-ray weak objects in our 3 4 using the AGN sample of the XMM-COSMOS survey sample because the timescale of a decline, 10 –10 years (Lusso et al. 2012), PG quasars, and WISSH quasars. (e.g., Schawinski et al. 2010), is much shorter than the 7.0 9.5 lifetime of ULIRGs (∼30 Myr; e.g., Hopkins et al. 2008; Their black hole masses are ∼10 –10 M for the XMM-COSMOS AGNs and PG quasars, and ∼109.5– Inayoshi et al. 2018). 11.0 Thus, we suggest that the AGNs in late merger 10 M for the WISSH quasars. Figure7 show the relation of bolometric correction and black hole mass of U/LIRGs are X-ray weak in nature. Teng et al.(2015) 7.0 point out that the X-ray weakness is also common in our sample. We find that our AGNs have MBH ∼ 10 – 8.5 broad absorption line (BAL) quasars (e.g., Luo et al. 10 M and do not follow the relation of Martocchia et al.(2017). We therefore suggest that the extreme 2013, 2014), where AGN-driven outflows may partially X-ray weakness may not be regulated by the black hole block the X-ray emission from the innermost region. By mass, but seems to be a common feature among AGNs Chandra follow-up studies of BAL quasars at z = 1.6– in U/LIRGs, many of which are gas-rich mergers (e.g., 2.7, Liu et al.(2018) estimate the fraction of X-ray weak Veilleux et al. 2002; Kartaltepe et al. 2010). AGNs is ≈6%–23% among the BAL population which is much larger than that among non-BAL quasars (.2%; Gibson et al. 2008). In fact, Mrk 231, a stage-D 6. DISCUSSION ULIRG in our sample, is known to be an X-ray weak 6.1. AGN Structure in U/LIRGs BAL quasar (Teng et al. 2014; Veilleux et al. 2016). In 6.1.1. X-ray Weakness this context, it is important to investigate correlation of the X-ray weakness (i.e., bolometric correction) with Applying the XCLUMPY model to the highest-quality the properties of various-scale (sub-pc to kpc) outflows broadband X-ray spectra currently available, we have es- based on multiwavelength observations. timated the absorption-corrected 2–10 keV luminosities and absorption column densities of the local U/LIRGs 6.1.2. Multiphase Outflows with the best accuracy so far. Combining them with the bolometric AGN luminosities estimated from the As mentioned in Section 5.3.2, molecular outflows IR data in various methods, we have derived their on large scales (&0.1 kpc) are often discovered in lo- bolometric-to-X-ray correction factors, κbol,X. Our cal U/LIRGs (e.g., Gonz´alez-Alfonsoet al. 2017; Laha main finding is that the AGNs in early mergers and et al. 2018 and the references therein). It is suggested nonmergers tend to follow the relation between bolomet- that the molecular outflow velocity exhibits correlations ric correction and Eddington ratio obtained for normal with stellar mass and SFR among star-forming galax- AGNs (Lusso et al. 2012), whereas those in late merg- ies (Chisholm et al. 2015). Whereas, on the basis of ers often show larger κbol,X values than the Lusso et al. (2012) relation by a factor of ∼10–100 (see also Teng 23 It is also possible that the column density in NGC 7674 is higher et al. 2015). As noted in Section 5.3.4, the discrepancies than our estimate as reported by (Gandhi et al. 2017), if the cannot be attributed to the uncertainties in the black reflected-dominated AGN with no direct detection of transmitted hole masses and bolometric luminosities. emission is assumed (see also AppendixB). 37

1.0 Stage-D(Late) 4 Stage-D(Late) 10 Stage-N Stage-N 0.5 UFO UFO 0.0 103

R 0.5 I , d X d , l E 1.0 o b g k 102 o

l 1.5

2.0 101 2.5

3.0 0 200 400 600 800 1000 0 200 400 600 800 1000 Non 1 1 Vout, mol [km s ] Vout, mol [km s ]

Figure 8. Bolometric-to-X-ray correction vs. molecular Figure 9. IR-based Eddington ratio vs. molecular outflow outflow velocity. Symbols and colors are the same as in Fig- velocity for the hard X-ray AGNs in the 10 stage-D and ure3. The small black circle marks the detection of UFOs 6 stage-N sources. Symbols and colors are the same as in (Mizumoto et al. 2019; Smith et al. 2019). The black dashed Figure3. The small black circle marks the detection of UFOs (Mizumoto et al. 2019; Smith et al. 2019). The AGNs whose line shows a typical value of κbol,X = 20. outflow velocities or mass outflow rates are not constrained (or the presences of molecular outflows have not yet been X-ray observations of galaxies hosting molecular out- reported) are plotted on the left side. flows, Laha et al.(2018) report that the outflow veloc- ˙ ity (Vout,mol) and mass transfer rate (Mout,mol) are more that outflow rates relative to the mass accretion rates strongly correlated with AGN luminosity than with star- are much larger in merging systems than in nonmerging burst luminosity. These facts imply that, although star- systems. bursts can drive massive molecular outflows, the pres- We find that the AGNs with molecular-outflow de- ence of an AGN always boosts the power of the outflow. tections have ionized outflows detected in the optical In the hard X-ray detected AGNs among our sample, band via blueshifted [O III] emission lines (see Ta- molecular outflows are detected from 10 stage-D mergers ble8). Furthermore, as shown in Figures8 and9, X- and 1 nonmerger, although the observations may not be ray spectral features of UFOs are found in four stage- complete. Figure8 plots the bolometric-to-X-ray correc- D mergers, IRAS F05189–2524, Mrk 231, Mrk 273, tion factors (κbol,X) against outflow velocities for AGNs NGC 6240S/NGC 6240N (dual-AGN)24 and in a stage- with molecular outflow detections (excluding two stage- N LIRG, NGC 1068 (Mizumoto et al. 2019; Smith et al. D mergers, Arp 220W and NGC 6240S/NGC 6240N, 2019). Their molecular outflows seem to be driven by since their bolometric AGN luminosities are not con- the AGN activities (see also e.g., Tombesi et al. 2015; strained). A strong positive correlation is noticeable, Fiore et al. 2017). This supports the analogy of late suggesting a link between the X-ray weakness and out- merger U/LIRGs with BAL QSOs as mentioned above. flow activity. Figure9 shows the relation between molecular-outflow velocity and Eddington ratio; here we include AGNs without molecular outflow detections. A positive correlation is suggested for stage-D mergers, supporting the AGN origin for the molecular outflows. It is noteworthy that the outflow velocity in the stage- N source (NGC 1068) is smaller than those in state- D mergers at similar Eddington ratios (log λEdd,IR ∼ −0.5–0.0). Moreover, molecular outflows in the other nonmergers have not been detected. These results imply that powerful outflows can be more efficiently launched 24 The results of the dual AGNs in NGC 6240S/NGC 6240N are from late mergers than from nonmergers due to envi- not presented in Section6, since the bolometric luminosities and SFRs of individual sources cannot be separately obtained. ronmental effects. In fact, Smethurst et al.(2019) show 38 Yamada et al.

Table 8. Properties of AGN and Starburst Activities for Hard X-ray Detected AGNs

(IR) ˙ Object logL[O IV] logLbol,AGN logSFR Vout,mol logMout,mol Ref.

[O IV] fAGN SED IRS −1 −1 −1 −1 −1 −1 −1 −1 (erg s ) (erg s ) (erg s ) (erg s ) (erg s )(M yr ) (km s )(M yr )

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) Stage-A NGC 833 <39.34 <41.64 ····················· NGC 835 39.98 ± 0.03 42.41 ± 0.33 43.76 ± 0.07† ·················· +0.10 NGC 6921 ··············· 0.20−0.19 ······ 1 +0.15 +0.05 MCG+04-48-002 40.72 ± 0.03 43.66 ± 0.34 43.98 ± 0.06 ··· 43.32−0.15 1.17−0.03 ······ 2 +0.08 +0.15 +0.04 NGC 7469 41.46 ± 0.02 44.92 ± 0.35 44.67 ± 0.06 44.95−0.07 44.66−0.15 1.63−0.03 ······ 2 +0.02 +0.02 (i) NGC 7674 41.94 ± 0.01 45.73 ± 0.36 45.07 ± 0.07 45.15−0.02 ··· 1.39−0.01 ······ 2 +0.15 +0.01 NGC 7679 41.36 ± 0.01 44.75 ± 0.35 43.98 ± 0.06 ··· 43.88−0.15 1.17−0.02 ······ 2 NGC 7682 ··························· Stage-B † +0.06 NGC 235 41.28 ± 0.01 44.61 ± 0.35 44.05 ± 0.06 [44.29−0.04]: ··· <0.96 ······ 3 +0.10 +0.34 CGCG 468-002W 40.79 ± 0.01 43.78 ± 0.34 44.55 ± 0.04 [44.10−0.16]: ··· 0.70−0.38 ······ 1 +0.07 +0.01 ESO 060-IG016 East <41.06 <44.58 44.83 ± 0.06 44.85−0.06 ··· 1.83−0.02 ······ 2 +0.06 Mrk 266B 42.00 ± 0.05 45.83 ± 0.36 [44.57 ± 0.07]: [44.60−0.09]: ··· <1.61 ······ 3 +0.06 Mrk 266A ······ [44.57 ± 0.07]: [44.60−0.09]: ··· <1.35 ······ 3 +0.02 +0.15 +0.02 IC 4518A 41.70 45.33 ± 0.36 ··· 44.42−0.02 43.85−0.15 1.20−0.02 ······ 2 +0.03 NGC 6286 <40.2 <43.11 44.06 ± 0.06 ······ 1.44−0.02 ······ 2 Stage-C +0.13 +0.05 MCG+12-02-001 <40.55 <43.71 43.92 ± 0.04 44.53−0.27 ··· 1.57−0.03 ······ 2 +0.09 +0.03 IRAS F06076–2139 <40.89 <44.29 44.34 ± 0.01 ··· 44.01−0.08 1.71−0.02 ······ 2 +0.08 +0.15 +0.03 NGC 3690 West 40.82 ± 0.06 43.83 ± 0.34 [45.01 ± 0.07]: [45.36−0.11]: 43.94−0.15 [1.85−0.03]: ······ 2 +0.08 +0.05 NGC 4922N 40.74 ± 0.08 43.70 ± 0.34 44.25 ± 0.05 44.81−0.07 ··· 1.31−0.03 ······ 2 +0.14 +0.04 (i) ESO 148-2 41.85 ± 0.07 45.58 ± 0.36 44.98 ± 0.03 45.26−0.17 ··· 1.93−0.03 ······ 2 Stage-D +0.04 NGC 34 <40.69 <43.95 43.74 ± 0.02 ······ 1.47−0.04 ······ 2 +0.05 +0.01 +0.03 (i∗) IRAS F05189–2524 42.05 ± 0.03 45.92 ± 0.36 45.58 ± 0.07 45.84−0.11 45.62−0.01 1.89−0.05 574 ± 50 2.431 2,a,b +0.48 +0.26 +0.03 (i) NGC 2623 40.84 ± 0.07 43.87 ± 0.34 44.24 ± 0.03 43.52−0.57 43.39−0.26 1.63−0.04 587 1.050 2,c +0.23 +0.03 +0.19 (i) IRAS F08572+3915 <41.37 <45.12 45.48 ± 0.09 46.31−0.33 45.57−0.05 1.46−0.38 800 ± 160 3.082 2,a +0.15 +0.05 +0.08 UGC 5101 41.42 ± 0.05 44.85 ± 0.35 45.05 ± 0.05 44.82−0.20 44.54−0.04 2.02−0.06 225 ± 50 ··· 2,a +0.10 +0.01 +0.05 (i∗) Mrk 231 <41.76 <45.78 45.94 ± 0.12 46.26−0.13 46.07−0.01 2.34−0.05 700 ± 140 3.02 2,a +0.29 +0.12 +0.02 (i) IRAS 13120–5453 <41.17 <44.77 44.57 ± 0.02 44.47−0.22 44.40−0.18 2.40−0.02 520 ± 150 2.113 2,a +0.21 +0.19 +0.04 (i∗) Mrk 273 42.2 ± 0.01 46.17 ± 0.37 45.35 ± 0.08 44.83−0.39 44.05−0.08 2.15−0.05 620 ± 124 2.778 2,a +0.15 +0.05 IRAS F14348–1447 <41.45 <45.25 44.99 ± 0.05 ··· 44.11−0.16 2.37−0.07 508 ± 50 ··· 2,a +0.65 +0.07 Arp 220W [<41.06]: [<44.24]: [44.87 ± 0.05]: ··· [42.52−1.61]: [2.35−0.07]: [153 ± 50]: ··· 2,a +0.35 +0.07 (i∗) NGC 6240S [41.48 ± 0.06]: [44.95 ± 0.35]: [44.61 ± 0.02]: [44.35−1.24]: ··· [1.99−0.04]: [400 ± 100]: [2.903]: 2,a +0.35 +0.07 (i∗) NGC 6240N [41.48 ± 0.06]: [44.95 ± 0.35]: [44.61 ± 0.02]: [44.35−1.24]: ··· [1.99−0.04]: [400 ± 100]: [2.903]: 2,a +0.29 +0.05 IRAS F17138–1017 <40.73 <44.02 43.98 ± 0.04 44.13−0.33 ··· 1.58−0.05 ······ 2 Stage-N +0.09 +0.03 (i∗) NGC 1068 41.81 ± 0.01 45.51 ± 0.36 45.04 ± 0.01 44.82−0.07 ··· 1.28−0.04 150 ± 100 1.924 2,a +0.05 +0.07 +0.02 UGC 2608 42.23 ± 0.01 46.22 ± 0.37 44.75 ± 0.09 44.66−0.04 44.61−0.07 1.37−0.02 ······ 2 +0.02 (i) NGC 1365 40.96 ± 0.01 44.07 ± 0.34 44.22 ± 0.03 ······ 1.20−0.02 ······ 4 +0.01 +0.15 +0.02 MCG–03-34-064 41.81 ± 0.01 45.51 ± 0.36 44.87 ± 0.04 45.02−0.01 44.52−0.15 0.96−0.04 ······ 2 +0.03 +0.15 +0.01 (i) NGC 5135 41.52 ± 0.01 45.02 ± 0.35 44.32 ± 0.06 44.24−0.03 43.72−0.15 1.34−0.01 ······ 2 +0.07 +0.15 +0.02 (i) NGC 7130 41.08 ± 0.03 44.27 ± 0.35 44.41 ± 0.04 44.40−0.04 43.60−0.15 1.48−0.03 ······ 2

Note—Columns: (1) object name; (2) logarithmic [O IV] 25.89 µm luminosity. The values are taken from Inami et al.(2013) except for Mrk 266B Mazzarella et al. (2012) and IC 4518A (Liu et al. 2014); (3) logarithmic bolometric AGN luminosity derived from the relation of [O IV] and AGN luminosities (Gruppioni et al. 2016); (4) logarithmic bolometric AGN luminosity derived from the bolometric AGN fraction (D´ıaz-Santos et al. 2017). The bolometric-to-IR correction factor of total luminosity is assumed to be 1.15. (5–6) logarithmic bolometric AGN luminosity derived from the 1–500 µm SED decomposition and Spitzer/IRS spectral fitting (Alonso-Herrero et al. 2012; Shangguan et al. 2019). The bolometric-to-IR correction factor of the AGN luminosity is assumed to be 3.0 (Delvecchio et al. 2014); (7) logarithmic SFR; (8–9) molecular outflow velocity and logarithmic mass outflow rate. The mark (i) means that ionized outflows are detected (Fischer et al. 2013; Rich et al. 2015; Cortijo-Ferrero et al. 2017a; Kakkad et al. 2018; Venturi et al. 2018; Smith et al. 2019; Boettcher et al. 2020; Fluetsch et al. 2021), and * means that UFOs are detected (Mizumoto et al. 2019; Smith et al. 2019); (10) References of the columns (7) and (8–9) marked as “1–4” and “a–c”, respectively. Values in brackets with “:” should be considered to be upper limits due to contamination from nearby IR sources. The error and upper limit are 1σ and 3σ level. References: (1) Pereira-Santaella et al.(2015); (2) Shangguan et al.(2019); (3) Howell et al.(2010); (4) Gruppioni et al.(2016); (a) Laha et al.(2018) and the references therein; (b) Gonz´alez-Alfonsoet al.(2017); (c) Lutz et al.(2020).

† The total IR luminosities are calculated by the 40–120 µm luminosity times 1.9 (see Lutz et al. 2018). 39

Table 9. Properties of AGN and Starburst Activities for Starburst-dominant or Hard X-ray Undetected Sources

(IR) ˙ Object logL[O IV] logLbol,AGN logSFR Vout,mol logMout,mol Ref.

[O IV] fAGN SED IRS −1 −1 −1 −1 −1 −1 −1 −1 (erg s ) (erg s ) (erg s ) (erg s ) (erg s )(M yr ) (km s )(M yr )

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) Stage-A NGC 838 40.29 ± 0.03 42.93 ± 0.33 43.43 ± 0.03† ·················· NGC 839 40.06 ± 0.23 42.54 ± 0.33 43.65 ± 0.04† ···············(i) ··· MCG+08-18-012 ··························· +0.14 +0.02 MCG+08-18-013 <39.90 <42.60 44.28 ± 0.01 43.77−0.25 ··· 1.43−0.02 ······ 1 MCG–01-26-013 ··························· +0.03 NGC 3110 <40.30 <43.28 44.01 ± 0.06 ······ 1.46−0.02 ······ 1 +0.02 +0.02 (i) NGC 4418 <40.49 <43.61 44.51 ± 0.22 ··· 44.47−0.02 1.28−0.02 324 0.799 1,a MCG+00-32-013 ························(i) ··· IC 5283 ··············· 1.03 ······ 2 MCG+01-59-081 ··············· 0.25 ······ 2 Stage-B MCG–02-01-052 ··············· 0.60 ······ 2 +0.03 +0.02 MCG–02-01-051 40.60 ± 0.16 43.46 ± 0.34 43.97 ± 0.05 44.76−0.04 ··· 1.56−0.02 ······ 1 † +0.06 NGC 232 40.93 ± 0.05 44.02 ± 0.34 44.13 ± 0.03 [44.29−0.04]: ··· 1.59 ······ 2 +0.20 +0.04 ESO 203-1 <41.04 <44.55 45.07 ± 0.26 ··· 44.05−0.21 1.76−0.04 ······ 1 +0.10 +0.09 CGCG 468-002E <40.11 <42.96 ··· [44.10−0.16]: ··· 1.18−0.15 ······ 3 ESO 060-IG016 West ··························· ESO 440-58 <39.96 <42.70 ········· 0.78 ······ 2 +0.02 MCG–05-29-017 40.17 ± 0.19 42.73 ± 0.33 43.85 ± 0.03 ······ 1.46−0.02 ······ 1 IC 4518B ··························· NGC 6285 <39.77 <42.38 43.15 ± 0.04† ······ 0.88 ······ 2 +0.02 NGC 6907 39.54 ± 0.12 41.66 ± 0.32 43.71 ± 0.04 ······ 1.19−0.02 ······ 1 NGC 6908 ··························· Stage-C +0.07 +0.02 +0.07 ESO 350-38 <40.77 <44.09 44.29 ± 0.09 45.21−0.11 44.93−0.01 0.77−0.08 ······ 1 IC 1623A ··············· 1.32 ······ 2 +0.03 +0.02 IC 1623B 40.45 ± 0.38 43.21 ± 0.34 44.43 ± 0.04 44.87−0.03 ··· 1.67−0.02 ······ 1 2MASS 06094601–2140312 ··························· +0.08 +0.03 NGC 3690 East 40.59 ± 0.39 43.44 ± 0.34 ··· [45.36−0.11]: ··· [1.85−0.03]: ······ 1 NGC 4922S ··· ··· ··· ··· ··· −0.89 ······ 2 +0.21 +0.03 II Zw 096 <41.28 <44.96 [44.28 ± 0.01]: [45.27−0.13]: ··· [1.98−0.05]: ······ 1 +0.21 +0.03 IRAS F20550+1655 SE <41.21 <44.84 [44.28 ± 0.01]: [45.27−0.13]: ··· [1.98−0.05]: ······ 1 Stage-D +0.11 +0.06 +0.02 ESO 374-IG032 <40.96 <44.41 44.77 ± 0.15 44.88−0.07 44.82−0.05 1.70−0.02 ······ 1 +0.08 +0.05 NGC 3256 40.69 ± 0.04 43.61 ± 0.34 43.98 ± 0.02 44.76−0.12 ··· 1.69−0.04 250 ± 100 1.041–1.204 1,b +0.09 +0.09 +0.02 (i) IRAS F10565+2448 <41.02 <44.52 44.33 ± 0.01 43.96−0.09 44.71−0.05 2.14−0.03 450 ± 90 2.477 1,b +0.32 +0.16 +0.02 IRAS F12112+0305 <41.36 <45.10 44.78 ± 0.03 44.15−0.23 43.75−0.14 2.33−0.03 237 ± 50 ··· 1,b +0.59 +0.18 +0.11 (i) IRAS F14378–3651 <41.17 <44.77 44.57 ± 0.02 44.01−0.85 43.64−0.11 2.16−0.06 800 ± 150 2.869 1,b +0.17 +0.14 +0.09 IRAS F15250+3608 <41.48 <45.30 44.98 ± 0.16 45.68−0.32 44.58−0.13 1.79−0.09 ······ 1 +0.65 +0.07 Arp 220E [<41.06]: [<44.24]: [44.87 ± 0.05]: ··· [42.52−1.61]: [2.35−0.07]: [153 ± 50]: ··· 1,b +0.07 IRAS F19297–0406 <41.71 <45.70 44.79 ± 0.03 ······ 2.39−0.04 532 ± 50 ··· 1,b +0.16 +0.06 +0.05 (i) ESO 286-19 <41.26 <44.93 45.08 ± 0.05 45.50−0.25 45.09−0.08 1.85−0.05 500 2.176 1,c Stage-N UGC 2612 ··························· +1.22 +0.02 IC 860 <39.98 <42.74 43.56 ± 0.03 ··· 40.73−1.32 1.27−0.02 ······ 1 +0.20 +0.02 NGC 5104 40.01 ± 0.31 42.46 ± 0.33 43.91 ± 0.04 ··· 43.23−0.20 1.32−0.02 ······ 1 +0.04 IRAS F18293–3413 40.74 ± 0.06 43.70 ± 0.34 44.22 ± 0.03 ······ 1.96−0.04 ······ 1 +0.02 NGC 7591 ··············· 1.18−0.02 ······ 1

Note—Columns: (1–10) same as in Table8. References: (1) Shangguan et al.(2019); (2) Howell et al.(2010); (3) Pereira-Santaella et al.(2015); (a) Lutz et al.(2020); (b) Laha et al.(2018); (c) Imanishi et al.(2017).

† The total IR luminosities are calculated by the 40–120 µm luminosity times 1.9 (see Lutz et al. 2018). 40 Yamada et al.

Table 10. Stellar and Black Hole Masses of the Hard X-ray Detected AGNs

Object logM∗ Ref. 1 logMBH Ref. 2

M∗ M–σ∗ Lbulge others Method (M )(M )(M )(M )(M )

(1) (2) (3) (4) (5) (6) (7) (8) (9) Stage-A

NGC 833 ········· 8.97 ··· 8.24 ± 0.40 L2µm 6,7 NGC 835 10.48 1 6.90 8.16 ··· 8.50 ± 0.40 L2µm 6,7 NGC 6921 11.16 ± 0.03 2 7.62 ± 0.20 ······ 8.60 M–σ(Ca) 8 MCG+04-48-002 11.13 ± 0.20 3 7.59 ± 0.48 7.50 ± 0.40 ··· 7.85 M–σ(Ca) 9,8 NGC 7469 11.18 ± 0.20 3 7.64 ± 0.48 7.61 ± 0.40 7.00 ± 0.14 6.97 ± 0.05 reverberation 9,10,11 NGC 7674 11.25 ± 0.20 3 7.71 ± 0.48 7.56 ± 0.44 8.50 ± 0.09 8.20 ± 0.50 plane equation 12,10,13

NGC 7679 10.79 ± 0.20 3 7.23 ± 0.48 6.77 ± 0.40 ··· 8.27 ± 0.40 L2µm 9,7

NGC 7682 10.53 1 6.96 7.28 ± 0.44 ··· 8.20 ± 0.40 L2µm 12,7 Stage-B

NGC 235 10.93 4 7.38 ··· 8.76 8.47 ± 0.40 L2µm 14,7 CGCG 468-002W 10.83 ± 0.05 2 7.27 ± 0.25 ······ 8.06 ± 0.50 M–σ([O III]) 9 ESO 060-IG016 East 10.90 ± 0.20 3 7.35 ± 0.48 ··· 8.24 ± 0.09 ······ 10 Mrk 266B [11.15 ± 0.20]: 3 [7.61 ± 0.48]: ··· 8.28 ± 0.07 ······ 10 Mrk 266A [11.15 ± 0.20]: 3 [7.61 ± 0.48]: ··· 8.37 ± 0.08 ······ 10 IC 4518A 11.12 ± 0.20 3 7.58 ± 0.48 7.48 ± 0.40 ········· 9

NGC 6286 11.07 ± 0.20 3 7.52 ± 0.48 ······ 8.43 ± 0.40 L2µm 7 Stage-C MCG+12-02-001 10.61 ± 0.20 3 7.04 ± 0.48 ··············· IRAS F06076–2139 10.86 ± 0.20 3 7.30 ± 0.48 ··············· NGC 3690 West 10.36 5 6.77 7.40 ± 0.47 ········· 15 NGC 4922N 11.24 ± 0.20 3 7.70 ± 0.48 7.87 ± 0.45 ········· 16† ESO 148-2 10.97 ± 0.20 3 7.42 ± 0.48 7.57 ± 0.50 ········· 17† Stage-D NGC 34 10.76 ± 0.20 3 7.20 ± 0.48 7.71 ± 0.52 8.56 ± 0.09 ······ 18,10 IRAS F05189–2524 10.93 ± 0.20 3 7.38 ± 0.48 7.43 ± 0.50 8.32 8.62 M–σ(Ca) 13,19,20 NGC 2623 10.60 ± 0.20 3 7.03 ± 0.48 7.61 ± 0.50 7.97 ± 0.07 7.88 ± 0.50 plane equation 13,10 IRAS F08572+3915 10.49 ± 0.20 3 6.91 ± 0.48 8.37 ± 0.50 7.16 ± 0.13 ······ 16†,10 UGC 5101 11.00 ± 0.20 3 7.45 ± 0.48 8.00 ± 0.50 8.98 ± 0.11 8.23 ± 0.50 plane equation 13,10 Mrk 231 11.51 ± 0.20 3 7.99 ± 0.48 7.18 ± 0.48 8.58 7.94 Hβ EW 21†,19,22 IRAS 13120–5453 11.33 ± 0.20 3 7.80 ± 0.48 ··· 9.07 ± 0.11 ······ 10 Mrk 273 10.99 ± 0.20 3 7.44 ± 0.48 8.49 ± 0.50 8.30 9.17 ± 0.05 maser 13,19,18 IRAS F14348–1447 11.14 ± 0.20 3 7.60 ± 0.48 7.59 ± 0.54 8.32 ± 0.07 ······ 21†,10 Arp 220W [10.97 ± 0.20]: 3 [7.42 ± 0.48]: [7.75 ± 0.46]: [8.18]: ······ 21†,19 NGC 6240S [11.50 ± 0.20]: 3 [7.98 ± 0.48]: 8.85 ± 0.05 8.76 ± 0.10 ······ 23,10 NGC 6240N [11.50 ± 0.20]: 3 [7.98 ± 0.48]: 8.56 ± 0.10 8.20 ± 0.07 ······ 23,10 IRAS F17138–1017 10.72 ± 0.20 3 7.16 ± 0.48 6.37 ± 0.53 ········· 24† Stage-N NGC 1068 11.06 ± 0.20 3 7.51 ± 0.48 7.59 ± 0.44 ··· 6.96 ± 0.02 maser 12,18 † UGC 2608 10.92 ± 0.20 3 7.37 ± 0.48 7.04 ± 0.46 ··· 8.50 ± 0.40 L2µm 24 ,7

NGC 1365 11.16 4 7.62 7.50 ± 0.51 8.88 8.50 ± 0.40 L2µm 18,14,7 MCG–03-34-064 11.09 ± 0.20 3 7.54 ± 0.48 7.65 ± 0.40 8.28 8.34 ± 0.50 plane equation 9,14,13

NGC 5135 11.03 ± 0.20 3 7.48 ± 0.48 7.29 ± 0.44 ··· 8.55 ± 0.40 L2µm 12,7

NGC 7130 11.09 ± 0.20 3 7.54 ± 0.48 7.59 ± 0.44 ··· 8.55 ± 0.40 L2µm 12,7 Average (Number of Objects) Stage-A (8) 10.93 (7) ··· 7.38 (7) 7.69 (7) 7.75 (2) 8.10 (8) ······ Stage-B (7) 10.97 (5) ··· 7.42 (5) 7.48 (1) 8.41 (4) 8.32 (3) ······ Stage-C (5) 10.81 (5) ··· 7.25 (5) 7.61 (3) ············ Stage-D (13) 10.95 (10) ··· 7.39 (10) 7.83 (11) 8.38 (11) 8.37 (5) ······ Stage-N (6) 11.06 (6) ··· 7.51 (6) 7.44 (6) 8.58 (2) 8.23 (6) ······ All (39) 10.95 (33) ··· 7.39 (33) 7.68 (28) 8.34 (19) 8.23 (22) ······

Note—Columns: (1) object name; (2–3) logarithmic stellar mass and their references; (4) logarithmic black hole mass derived from the relation of stellar mass and black hole mass (Reines & Volonteri 2015); (5) logarithmic black hole mass derived from the M–σ∗ relation; (6) logarithmic black hole mass derived from the photometric bulge luminosity; (7–8) logarithmic black hole mass and the method for estimation; (9) references of the results in columns (5–7). Values in brackets with “:” should be considered to be upper limits since the components of two galaxies are not separated. The error is 1σ. References: (1) Koss et al.(2011); (2) Pereira-Santaella et al.(2015); (3) Shangguan et al.(2019); (4) Howell et al.(2010); (5) Marleau et al.(2017); (6) Gonz´alez-Mart´ınet al.(2009); (7) Caramete & Biermann(2010); (8) Koss et al.(2016); (9) Alonso-Herrero et al.(2013); (10) Haan et al.(2011); (11) Bentz & Katz(2015); (12) Marinucci et al.(2012); (13) Dasyra et al.(2011); (14) Winter et al.(2009); (15) Ptak et al.(2015); (16) SDSS Data Release 16; (17) Dasyra et al.(2006a); (18) Izumi et al.(2016) and therein references; (19) Veilleux et al. (2009b); (20) Xu et al.(2017); (21) Dasyra et al.(2006b); (22) Kawakatu et al.(2007); (23) Kollatschny et al.(2020); (24) HyperLeda. The † means that the M–σ∗ relation in G¨ultekinet al.(2009) is adopted. 41

Table 11. Summary of the AGN Properties Derived from the X-ray/IR Luminosities and Torus Parameters

(IR;lit,ave) (lit,ave) (22) (24) Object logL2−10 logL10−50 logLbol,AGN logMBH logλEdd(X/IR) κbol,X CT CT −1 −1 −1 (erg s ) (erg s ) (erg s )(M )

(1) (2) (3) (4) (5) (6) (7) (8) (9) Stage-A +0.25 +0.25 +0.25 +0.04 +0.01 NGC 833 41.99−0.24 41.97−0.24 ··· 8.61 −3.42−0.24/ ······ 0.63−0.03 0.43−0.04 +0.13 +0.13 +0.39 +0.13 +0.39 +17 +0.04 +0.01 NGC 835 42.06−0.03 42.37−0.03 43.09−0.39 7.85 −2.60−0.03/−2.87−0.39 11−6 0.61−0.01 0.45−0.02 +0.37 +0.37 +0.37 a a NGC 6921 42.80−0.44 43.01−0.44 ··· 8.11 −2.11−0.44/ ······ 0.73 0.31 +0.15 +0.15 +0.36 +0.15 +0.36 +23 +0.18a +0.02 MCG+04-48-002 42.44−0.15 42.65−0.15 43.66−0.36 7.64 −2.00−0.15/−2.09−0.36 16−10 0.82−0.12 0.46−0.14 +0.03 +0.03 +0.33 +0.03 +0.33 +39 +0.04 +0.07 NGC 7469 43.26−0.02 43.33−0.02 44.80−0.33 7.30 −0.84−0.02/−0.60−0.33 34−18 0.48−0.05 0.18−0.03 +0.33 +0.33 +0.35 +0.33 +0.35 +1071 +0.00a +0.07 NGC 7674 42.59−0.23 42.80−0.23 45.32−0.35 7.99 −2.20−0.23/−0.78−0.35 529−328 1.00−0.01 0.68−0.15 +0.06 +0.06 +0.37 +0.06 +0.37 +99 +0.21a NGC 7679 42.34−0.04 42.47−0.04 44.20−0.37 7.42 −1.88−0.04/−1.32−0.37 73−42 0.26−0.26 ··· +0.06 +0.06 +0.06 +0.00a NGC 7682 41.94−0.06 42.05−0.06 ··· 7.48 −2.33−0.06/ ······ 1.00−0.24 ··· Stage-B +0.18 +0.18 +0.41 +0.18 +0.41 +21.0 +0.13 +0.02 NGC 235 43.28−0.16 43.47−0.16 44.33−0.41 8.20 −1.72−0.16/−1.97−0.41 11.4−7.3 0.75−0.05 0.43−0.08 +0.04 +0.04 +0.40 +0.04 +0.40 +33 +0.01 +0.22a CGCG 468-002W 42.84−0.03 43.07−0.03 44.17−0.40 7.67 −1.63−0.03/−1.60−0.40 21−13 0.52−0.01 0.01−0.01 +0.07 +0.07 +0.11 +0.07 +0.11 +271 ESO 060-IG016 East 41.94−0.08 42.05−0.08 44.84−0.10 7.79 −2.65−0.08/−1.06−0.10 781−197 ······ +0.39 +0.60 +0.39 +0.60 +2125 Mrk 266B 43.13−0.36 ··· 45.83−0.60 8.28 −1.95−0.36/−0.55−0.60 504−403 ······ +0.04 +0.04 Mrk 266A 41.60−0.02 ······ 8.37 −3.57−0.02/ ············ +0.06 +0.06 +0.37 +0.06 +0.37 +69 +0.02 +0.03 IC 4518A 42.83−0.08 42.94−0.08 44.53−0.37 7.53 −1.49−0.08/−1.10−0.37 50−29 0.67−0.02 0.32−0.04 +1.21 +1.21 +0.10 +1.21 +0.10 +1719 NGC 6286 42.01−0.23 42.32−0.23 44.06−0.10 7.98 −2.77−0.23/−2.02−0.10 112−49 ······ Stage-C +0.33 +0.33 +0.16 +0.33 +0.16 +400 MCG+12-02-001 41.75−0.08 41.86−0.08 44.22−0.32 7.04 −2.09−0.08/−0.92−0.32 297−158 ······ +0.15 +0.15 +0.11 +0.15 +0.11 +52 IRAS F06076–2139 42.18−0.14 42.29−0.14 44.17−0.09 7.30 −1.92−0.14/−1.23−0.09 98−32 ······ +0.34 +0.34 +0.44 +0.34 +0.44 +43 +0.00a +0.03 NGC 3690 West 42.66−0.32 42.48−0.32 43.89−0.44 7.09 −1.22−0.32/−1.30−0.44 17−12 1.00−0.01 0.97−0.04 +0.20 +0.20 +0.34 +0.20 +0.34 +264 NGC 4922N 42.00−0.18 42.11−0.18 44.25−0.33 7.79 −2.59−0.18/−1.63−0.33 181−105 ······ +0.24 +0.24 +0.37 +0.24 +0.37 +1353 ESO 148-2 42.38−0.28 42.49−0.28 45.27−0.38 7.49 −1.91−0.28/−0.32−0.38 773−511 ······ Stage-D +0.10 +0.10 +0.03 +0.10 +0.03 +18 NGC 34 41.90−0.10 42.01−0.10 43.74−0.03 7.82 −2.72−0.10/−2.19−0.03 69−15 ······ +0.01 +0.01 +0.31 +0.01 +0.31 +216 +0.01 +0.01 IRAS F05189–2524 43.42−0.02 43.26−0.02 45.74−0.32 7.94 −1.32−0.02/−0.30−0.32 208−108 0.56−0.01 0.39−0.02 +0.11 +0.11 +0.53 +0.11 +0.53 +1770 NGC 2623 40.90−0.11 41.01−0.11 43.75−0.59 7.62 −3.52−0.11/−1.97−0.59 709−530 ······ b +0.06 +0.06 +0.24 +0.06 +0.24 +7854 IRAS F08572+3915 41.77−0.07 41.88−0.07 45.78−0.33 7.48 −2.51−0.07/+0.20−0.33 10390−5601 ······ +0.25 +0.25 +0.32 +0.25 +0.32 +73 +0.24a +0.01a UGC 5101 43.15−0.15 43.46−0.15 44.81−0.34 8.17 −1.82−0.15/−1.45−0.34 47−27 0.56−0.56 0.41−0.41 +0.02 +0.02 +0.15 +0.02 +0.15 +1125 +0.13 Mrk 231 42.65−0.02 42.97−0.02 46.09−0.17 7.92 −2.07−0.02/+0.07−0.17 2719−879 0.70−0.08 ··· +0.59 +0.59 +0.30 +0.59 +0.30 +741 IRAS 13120–5453 42.17−0.11 42.28−0.11 44.48−0.27 8.43 −3.07−0.11/−2.06−0.27 204−100 ······ +0.21 +0.21 +0.39 +0.21 +0.39 +188 +0.04 +0.02 Mrk 273 43.07−0.21 43.24−0.21 45.10−0.45 8.35 −2.08−0.21/−1.35−0.45 106−72 0.71−0.04 0.44−0.03 +0.93 +0.93 +0.18 +0.93 +0.18 +563 IRAS F14348–1447 42.70−0.40 42.81−0.40 44.55−0.20 7.84 −1.94−0.40/−1.39−0.20 71−45 ······ b +0.02 +0.02 Arp 220W 41.59−0.02 41.70−0.02 ········· / ············ +0.20 +0.20 NGC 6240S 43.72−0.19 ······ 8.81 −1.89−0.19/ ············ +0.24 +0.24 NGC 6240N 43.30−0.20 ······ 8.38 −1.88−0.20/ ············ b +0.09 +0.09 +0.34 +0.09 +0.34 +299 IRAS F17138–1017 41.68−0.06 41.79−0.06 44.05−0.39 6.76 −1.89−0.06/−0.81−0.39 238−141 ······ Stage-N +0.07 +0.35 +0.07 +0.35 +78 NGC 1068 43.34−0.08 ··· 45.12−0.35 7.35 −0.81−0.08/−0.33−0.35 60−34 ······ +0.19 +0.19 +0.32 +0.19 +0.32 +40 +0.31a +0.23a UGC 2608 43.59−0.25 43.70−0.25 45.06−0.32 7.64 −0.84−0.25/−0.68−0.32 29−18 0.45−0.45 0.28−0.28 +0.01 +0.40 +0.01 +0.40 +270 NGC 1365 41.90−0.01 ··· 44.15−0.40 8.13 −3.02−0.01/−2.08−0.40 176−107 ······ +0.06 +0.06 +0.32 +0.06 +0.32 +58 +0.02 +0.01 MCG–03-34-064 43.27−0.07 43.24−0.07 44.98−0.32 7.95 −1.48−0.07/−1.08−0.32 51−27 0.79−0.02 0.50−0.01 +0.42 +0.41 +0.32 +0.42 +0.32 +25 +0.19a +0.17a NGC 5135 43.30−0.26 43.49−0.26 44.33−0.32 7.77 −1.27−0.26/−1.55−0.32 11−7 0.44−0.44 0.26−0.26 +0.31 +0.31 +0.32 +0.31 +0.32 +35 +0.12 +0.14 NGC 7130 42.87−0.25 43.09−0.25 44.17−0.31 7.89 −1.82−0.25/−1.82−0.31 20−12 0.88−0.44 0.52−0.26

Note—Columns: (1) object name; (2–3) logarithmic absorption-corrected X-ray luminosities in the 2–10 keV and 10–50 keV bands. The errors are estimated by fixing the photon index at the best-fit value; (4) average value of the logarithmic bolometric AGN luminosities (excluding the values of upper limits) derived from the four independent estimates based on the IR properties in Table8. The error is converted to the 90% confidence level by multiplying a factor of 1.65; (5) average value of the logarithmic black hole mass derived from the four independent estimates in Table 10; 38 (6) logarithmic Eddington ratio (Lbol/LEdd). Here, the Eddington luminosity is defined as 1.26 × 10 MBH/M . The bolometric luminosities are (IR;lit,ave) obtained from 20L2−10 and Lbol,AGN , respectively; (7) bolometric-to-X-ray (2–10 keV) correction factor; (8–9) torus covering factor derived from 22 −2 24 −2 the torus parameters for Compton-thin (NH ≥ 10 cm ) and CT (NH ≥ 10 cm ) material, respectively, for the AGNs whose torus angular widths (σ) are constrained. a The parameter of torus angular width reaches a limit of its allowed range. b X-ray luminosities and bolometric correction factors are uncertain due to the assumption of fbin = 10% for these three objects. 42 Yamada et al.

These results imply that the obscuration in these three AGNs is caused by in/outflowing materials within the torus scale (a few to tens of pc), where the gravita- tional potential of the black hole dominates over that of the host galaxy.25 Alternatively, the absorption could be caused by host-galaxy interstellar medium located far away from the torus. We infer this possibility un- likely, however, because dramatic variability of the ab- sorption column density within ∼10 years is detected in IRAS F05189–2524 (Section 6.1.5). The simulations (e.g., Hopkins et al. 2006; Angl´es-Alc´azaret al. 2017; Kawaguchi et al. 2020) and observations (e.g., Satyapal et al. 2014; Kocevski et al. 2015; Ricci et al. 2017a; Ya- mada et al. 2019) show that mergers can trigger quasi- spherical inflows of material onto the inner pc-scale re- Figure 10. Line-of-sight hydrogen column density vs. IR- gion of the systems, which may also produce powerful based Eddington ratio. The black continuous line shows the outflows (see Section 6.1.2). The variability of NH and eff effective Eddington limit (λEdd; Fabian et al. 2008, 2009). the detection of UFOs are consistent with the scenario The pink triangle area represents the “forbidden” region ob- that the obscuration in these three AGNs is caused by LoS 22 tained by the effective Eddington limit and the NH = 10 the chaotic in/outflows in the nuclear region. cm−2 limit, below which absorption by outer dust lanes may become important. Symbols and colors are the same as in 6.1.4. Torus Covering Factor and Eddington Ratio Figure3. The black empty circles, empty squares, and filled As mentioned in Section 5.2, the large fractions of ob- points mark the detections of strong molecular outflows with −1 scured AGNs and CT AGNs in late mergers suggest they velocities of Vout,mol ≥ 500 km s (e.g., Gonz´alez-Alfonso et al. 2017; Laha et al. 2018 and the references therein), are deeply buried by surrounding gas and dust. On the ionized outflows (e.g., Rich et al. 2015; Kakkad et al. 2018; basis of the fraction of obscured AGNs in the Swift/BAT Fluetsch et al. 2021), and UFOs (Mizumoto et al. 2019; 70-month catalog, Ricci et al.(2017b) report that the Smith et al. 2019), respectively. torus covering factors by Compton-thin material become smaller in AGNs with larger Eddington ratios due to ra-

6.1.3. NH–λEdd Diagram diation pressure from the nuclei. Here we quantitatively investigate whether the covering fractions of our AGN In Figure 10, we plot our sample in the NH–λEdd dia- sample follow the Ricci et al.(2017b) relation obtained gram, which is useful to examine the effect of radiation from normal AGNs. pressure to obscuring material around an AGN (Fabian An advantage of the XCLUMPY model is that the et al. 2008, 2009; Kakkad et al. 2016; Ricci et al. 2017b; torus covering factors (CT) of the individual AGNs can Ishibashi et al. 2018). The horizontal line shows the be constrained by using the torus parameters: the equa- 22 −2 Equ NH = 10 cm limit below which absorption by outer torial column density (NH ) and torus angular width dust lanes may become important (Fabian et al. 2008, (σ). In the geometry of the XCLUMPY, the torus cov- 22 −2 2009). The pink triangle area above it is called as “for- ering factors for Compton-thin (NH ≥ 10 cm ) ma- bidden” region where dusty clouds within the sphere terial can be calculated by Equation (6) in Ogawa et al. of influence of the black hole are pushed away by radia- (2021): tion pressure against the gravitational force by the black ! r   hole and hence cannot survive in a stationary state. (22) Equ 22 −2 CT = sin σ In NH /(10 cm ) , (4) We find that six AGNs in stage-D mergers host both of ionized outflows (empty squares) and strong molecu- Equ 24 −2 −1 and if NH ≥ 10 cm , the value for CT material is lar outflows with Vout,mol ≥ 500 km s (empty circles), r ! and three of them with λEdd 0.5 (IRAS F05189–2524,   & (24) Equ 24 −2 IRAS F08572+3915, and Mrk 231) are located within CT = sin σ In NH /(10 cm ) . (5) the forbidden region. Note that IRAS F05189–2524 and Mrk 231 show UFOs (Mizumoto et al. 2019; Smith et al. 2019), although IRAS F08572+3915 (with the highest 25 The presence of molecular outflows in some objects with lower λEdd) is too faint to examine the presence of an UFO Eddington ratios could also be explained if they have column with the current X-ray data. densities sensitive to radiation pressure outside the line of sight. 43

1.0 1.0 ) ) 2 2

2 0.8 2 0.8 ( ( T T C C

: :

r r o o

t 0.6 t 0.6 c c a a F F

g 0.4 g 0.4 n n

i Ricci+17 i Ricci+17 r r

e Stage-A(Early) e Stage-A(Early)

v Stage-B(Early) v Stage-B(Early) o o

C 0.2 Stage-C(Late) C 0.2 Stage-C(Late) Stage-D(Late) Stage-D(Late) Stage-N Stage-N 0.0 0.0 4 3 2 1 0 4 3 2 1 0 log Edd, X log Edd, IR

Figure 11. Left panel: torus covering factor vs. X-ray based Eddington ratio assuming κbol,X = 20. Right panel: torus covering factor vs. IR-based Eddington ratio. The black solid curve and gray shaded area represent the relation and its 1σ dispersion found by Ricci et al.(2017b) for AGNs in the Swift/BAT 70-month catalog. Symbols and colors are the same as in Figure3.

The results are listed in Table 11. These correspond relation.28 However, we find that the AGNs with the to the covering factors defined in Ricci et al.(2017b), highest Eddington ratios (log λEdd,IR ∼ 0) among our (22) (24) sample, IRAS F05189–2524 and Mrk 231 (both stage- who statistically estimate CT and CT from the frac- (22) tions of the obscured and CT AGNs among the whole D mergers), have larger covering factors (CT ∼ 0.6) Swift/BAT AGNs as a function of Eddington ratio. than the expected values for normal AGNs at similar Ed- Figure 11 plots the torus covering factors against Ed- dington ratios. It is noteworthy that both objects are dington ratio. The Eddington ratios are calculated located in the forbidden region in the NH–λEdd diagram from the bolometric luminosities estimated from the X- (Section 6.1.3). These facts imply that these AGNs are ray (left) or IR (right) results. In the case of normal obscured by dusty in/outflows with large covering frac- AGNs, Tanimoto et al.(2020) and Ogawa et al.(2021) tions within the torus scale. It would be also possible show that the covering factors derived from XCLUMPY, that the nuclei in these gas-rich mergers are embedded are in good agreement with the relation of Ricci et al. by high amounts of material in the inner regions of the (2017b) by referring to the X-ray luminosities.26 By host galaxies at larger scales than the tori. We infer contrast, the covering factors of our sample become sys- that the presence of such torus-scale in/outflows and/or tematically smaller than the Ricci et al.(2017b) relation host-galaxy scale material enhances the fraction of CT when we adopt the X-ray based Eddington ratios by as- AGNs in late mergers (Section 5.2). 27 suming κbol,X = 20 (as done in Ricci et al. 2017b). LoS Since we have revealed that AGNs in U/LIRGs are X- 6.1.5. Dramatic Variability of NH in Late Mergers ray weak (Section 6.1.1), we find it more appropriate to The massive transportation of gas and dust in rapidly refer to the IR based Eddington ratios for this discus- accreting AGNs in late mergers is also supported by vari- sion. ability of the line-of-sight hydrogen column density. As The right panel of Figure 11 shows that the cover- illustrated in Figure 12, the AGN in IRAS F05189–2524, ing factors of U/LIRGs estimated with the XCLUMPY +0.31 which has large Eddington ratio (logλEdd = −0.30−0.32) model are mostly consistent with the Ricci et al.(2017b) (22) and covering factor (CT = 0.56 ± 0.01), shows sig- LoS nificant variability in the column density, from NH = 26 Zhao et al.(2020) suggest that the covering factors estimated (7.5 ± 0.1) × 1022 cm−2 in the Chandra, XMM-Newton, with the homogeneous torus model borus02 (Balokovi´cet al. and NuSTAR observations (in 2001–2002 and 2013– 2018) are also consistent with the relation in Ricci et al.(2017b). 2016) to >2.3 × 1024 cm−2 in the Suzaku observations 27 Even if the empirical relation between bolometric correction and Eddington ratios (e.g., Lusso et al. 2012) is taken into account for (in 2006). We confirm that the hard X-ray spectra ob- −1 AGNs with λEdd & 10 , e.g., κbol,X ∼ 100, it has little effect on our discussion. 28 −1 The trend at λEdd . 10 is also consistent with the IR-based results for z < 0.1 SDSS quasars by Toba et al.(2021b). 44 Yamada et al.

normal AGNs in nonmergers must be attributed to the 1025 environmental effects in late mergers. Simulations show that massive chaotic inflows toward the SMBHs may be produced in these systems. We discuss possible physical mechanisms to account 24

] 10 2 CT AGN for the X-ray weakness of the AGNs in late mergers m

c (see also Laha et al. 2018 for galaxies with molecular [

S

o outflows). As mentioned in Section 6.1.1, it cannot be H L N 1023 attributed to the current decline in the AGN activities but is likely to be associated with AGN-driven strong outflows. The X-ray luminosity could be suppressed if ESO 148-2 (stage-C) 1022 F05189-2524 (stage-D) a part of the hot corona responsible for Comptonization 2000 2005 2010 2015 2020 is destroyed by quasi-spherical inflows. It is unlikely, Date however, that inflowing material directly reaches the Figure 12. Line-of-sight hydrogen column density against hot corona region, which is very compact (<10rg where observation date for ESO 148-2 (a stage-C merger) and IRAS rg is the gravitational radius; e.g., Fabian et al. 2015). F05189–2524 (a stage-D merger). As a more plausible scenario, the analogy with BAL quasars suggests the possibility that the X-rays are at- tenuated by dust-free partial absorbers due to optically- served with NuSTAR and Suzaku/HXD show little flux thick “failed winds” in the inner regions of the obscur- variability, and that this is truly caused by variability in ing torus (Luo et al. 2013, 2014). In UV-line driven the absorption.29 The stage-C ULIRG ESO 148-2 also wind models (e.g., Czerny et al. 2017; Nomura & Ohsuga shows large variability in the hydrogen column density. 2017)30, a wind once launched from an inner region of 2 3 By conducting an extensive X-ray spectral variability the disk (at ∼ 10 –10 rg) is overionized by X-ray ir- study of 20 Compton-thin AGNs, Laha et al.(2020) infer radiation as the height increases, lose the UV opacity, that the presence of compact-scale (a few pc) inhomoge- and eventually falls back into the disk (failed winds). neous gas, which show strong variability in full-covering Under the presence of chaotic quasi-spherical inflows in 20 23 −2 absorption of NH ∼ 10 –10 cm , and a long-lived late mergers, the densities and covering factors of these population of clumpy clouds detected as partial-covering failed winds may be enhanced as material reaching the 21 23.5 −2 absorbers with NH ∼ 10 –10 cm . Although there inner disks could serve as ingredients of the wind. Then, are only two examples showing dramatic variability in these enhanced failed winds, which are dust free and do our sample, the observed transitions between Compton- not re-emit in the IR band, more efficiently block X-rays thin and CT absorption column densities in late mergers from the central regions, making the AGN SEDs ap- suggest that the intense in/outflows may produce strong parently X-ray weaker compared with normal AGNs.31 turbulence and even much thicker transient absorbers Thanks to the attenuation of X-rays, UV-driven winds than in normal AGNs. (UFOs) can be more easily launched at larger radii in AGNs. Thus, this scenario also explains the reason why 6.1.6. Unified View of AGNs in Late Merger U/LIRGs the AGN-driven winds (in the forms of UFOs, ionized winds, and molecular outflows) are more developed in To summarize, we have shown that the AGNs in late late mergers than in nonmerging systems. mergers are X-ray weak (i.e., have large bolometric cor- In Figure 13, we compare our schematic views of rections) compared with normal AGNs at the same Ed- AGNs in late mergers and nonmergers. Mid-IR and dington ratios (Section 5.3.4). A large fraction of them show evidence for multiphase outflows, which are driven by the AGNs (Section 6.1.2). Even high Eddington- 30 When the material near the disk surface is in a low-ionization ratio AGNs in late mergers have large torus covering fac- state, the radiation force on UV line transitions (the bound– tors, which are likely contributed by variable in/outflows bound transition of metals) is 10–1000 times larger than the ra- diation force due to Thomson scattering (Stevens & Kallman (Sections 6.1.3, 6.1.4, and 6.1.5). These differences from 1990), leading to a high velocity disk wind. 31 We note that to explain the X-ray weakness of a high-Eddington ratio AGN, Veilleux et al.(2016) propose strong self-shadowing 29 Hence, this variability is different from that seen in a changing- effects by geometrically thick disks, so called “slim disks”, look AGN, which is accompanied by a dramatic change in the where the photon trapping and advection are important (e.g., absorption-corrected X-ray luminosity (e.g., Noda & Done 2018; Abramowicz et al. 1988). Ruan et al. 2019; Ricci et al. 2020, 2021b). 45

Narrow line region

1 kpc Molecular outflow

Ionized outflow

UFO Corona Dusty torus

0.1 pc 1 pc 10 pc 100 pc 1 kpc Narrow line region Molecular outflow 1 kpc

Ionized outflow

Chaotic inflow

X-ray obscurer

UFO Corona Dusty torus

0.1 pc 1 pc 10 pc 100 pc 1 kpc

Figure 13. Schematic pictures of AGN structure in nonmergers (top) and late mergers (bottom). Light pink, dark pink, and orange circles represent the chaotic quasi-spherical inflows, dusty torus region, and outflowing material, respectively. In a late merger, X-ray emission from the hot corona is effectively blocked by optically-thick failed winds, and stronger UV-driven winds (UFOs) are launched than in a nonmerger (see text). In the high-Eddington ratio AGN in a late merger, a part of the inflowing material is blown away by the radiation pressure. These inflows and/or outflows make the AGN deeply “buried”.

X-ray studies of nonmerger AGNs (e.g., Yamada et al. affected by chaotic quasi-spherical inflows due to the 2019, 2020) indicate that they are not deeply buried galaxy collision. The massive inflow produces optically- by gas and dust. Numerical simulations show that thick failed winds around the corona that works as X- the innermost torus structure is shaped by radiation- ray obscurers (see Section 6.1.4), and hence powerful driven fountain-like outflows (e.g., Wada et al. 2018), UV-line driven winds (UFOs) are launched. Moreover, which are confirmed by recent ALMA observations (e.g., a part of inflowing material may be picked up to be- Izumi et al. 2018). Whereas, the AGNs in late merg- come radiation-driven dusty outflows at high Eddington ing ULIRGs (e.g., IRAS F05189–2524 and Mrk 231) are ratios as proposed by Smethurst et al.(2019). 46 Yamada et al.

Table 12. Upper Limits of AGN Luminosities for Starburst-dominant or Hard X-ray Undetected Sources

(pre;[O IV]) (lim) Object logL2−10 logL2−10 AGN Flag

logNH=23 logNH=24 logNH=24.5 (1) (2) (3) (4) (5) (6)

Stage-A NGC 838 41.92 ± 0.11 <40.96 <41.55 <42.69 n NGC 839 41.72 ± 0.23 <40.79 <41.39 <42.53 n MCG+08-18-012 ··· <41.10 <41.69 <42.82 n MCG+08-18-013 <41.71 <40.99 <41.57 <42.70 n MCG–01-26-013 ··· <40.61 <41.21 <42.35 n NGC 3110 <42.03 <41.01 <41.60 <42.74 n NGC 4418 <42.19 <40.09 <40.68 <41.82 n MCG+00-32-013 ············ n IC 5283 ············ n MCG+01-59-081 ············ n Stage-B MCG–02-01-052 ··· <41.14 <41.73 <42.85 n MCG–02-01-051 42.18 ± 0.17 <41.19 <41.77 <42.90 n NGC 232 42.47 ± 0.10 ········· n ESO 203-1 <42.65 <41.38 <41.95 <43.06 n? CGCG 468-002E <41.88 ········· n ESO 060-IG016 West ············ n ESO 440-58 <41.76 <40.97 <41.55 <42.68 n MCG–05-29-017 41.81 ± 0.20 ········· n IC 4518B ············ n NGC 6285 <41.60 <40.64 <41.23 <42.36 n NGC 6907 41.27 ± 0.18 <40.73 <41.32 <42.46 n NGC 6908 ············ n Stage-C ESO 350-38 <42.42 <40.96 <41.54 <42.67 n IC 1623A ··· <41.56 <41.88 <42.66 n(SB) IC 1623B 42.06 ± 0.34 ········· n 2MASS 06094601–2140312 ············ n NGC 3690 East 42.18 ± 0.35 ········· n NGC 4922S ············ n II Zw 096 <42.86 <41.72(u) <42.29(u) <43.41(u) n?(u) IRAS F20550+1655 SE <42.80 <41.72(u) <42.29(u) <43.41(u) n?(u) Stage-D ESO 374-IG032 <42.58 <41.24 <41.82 <42.94 n NGC 3256 42.26 ± 0.10 <40.94 <41.26 <42.05 n(SB) IRAS F10565+2448 <42.64 <41.18 <41.75 <42.87 n IRAS F12112+0305 <42.93 <41.81 <42.37 <43.47 n? IRAS F14378–3651 <42.77 <41.99 <42.54 <43.65 Y? IRAS F15250+3608 <43.04 <41.73 <42.30 <43.41 n? Arp 220E <42.67(u) <41.06(u) <41.38(u) <42.16(u) n(u) IRAS F19297–0406 <43.25 <42.43 <42.98 <44.08 n?

Table 12 continued 47 Table 12 (continued)

(pre;[O IV]) (lim) Object logL2−10 logL2−10 AGN Flag

logNH=23 logNH=24 logNH=24.5 (1) (2) (3) (4) (5) (6)

ESO 286-19 <42.84 <41.69 <42.26 <43.38 n? Stage-N UGC 2612 ··· <41.16 <41.75 <42.89 n IC 860 <41.77 <40.21 <40.80 <41.94 n NGC 5104 41.68 ± 0.29 <41.16 <41.75 <42.88 n IRAS F18293–3413 42.31 ± 0.11 <41.20 <41.79 <42.92 n NGC 7591 ··· <40.79 <41.38 <42.51 n

Note—Columns: (1) object name; (2) predicted value of logarithmic absorption-corrected 2–10 keV AGN luminosity derived from the relation of [O IV] 25.89 µm and X-ray luminosities in Liu et al.(2014). The values should be upper limits due to the X-ray weakness and contamination from starburst emission; (3–5) 3σ upper limit of the absorption- LoS −2 corrected 2–10 keV AGN luminosity based on the 8–24 keV net count rates assuming log(NH /cm ) = 23, 24, and 24.5, respectively. For the starburst-dominant sources detected with >3σ level in the 8–24 keV (IC 1623A and NGC 3256), we utilized the 20–30 keV count rates, which are non-detection but less affected by the confusion of starburst emission; (6) Flag of a detectable AGN candidate in X-rays. Possible AGNs whose X-ray luminosity could be larger than 1043 erg s−1 based on its upper limits are described as Y? and n?, both of which are divided on whether the Chandra observations indicate the presence of an AGN or not, respectively (Iwasawa et al. 2011a; Torres-Alb`a et al. 2018). Whereas, n(SB) and n mean that a starburst-dominant source with >3σ detection or non-detection in the 8–24 keV band, respectively. The (u) means that the two nuclei are not clearly separated.

45 Liu+14(Sy2) Stage-A(Early) 6.2. Upper Limits of AGN Luminosities of Hard X-ray Stage-B(Early) 44 Undetected Sources Stage-C(Late) Stage-D(Late) To unveil the X-ray properties of all targets in Stage-N 0

1 43 our sample, here we evaluate the upper limits of 2 the absorption-corrected X-ray luminosities of possible L g o AGNs in the hard X-ray undetected sources. Over half l 42 of our targets (44/84 galaxies) in local U/LIRGs are starburst-dominant or not detected with NuSTAR in 41 the 8–24 keV band. As we mentioned in Section 4.2.2, the spectra of the two hard X-ray detected sources and 40 27 undetected sources are reproduced by adopting the 39.5 40.0 40.5 41.0 41.5 42.0 42.5 logL starburst-dominant model, whereas the spectra of the [O IV] others are not available due to few statistics even by Figure 14. Absorption-corrected 2–10 keV luminosity vs. combining the soft X-ray observation data. [O IV] 25.89 µm luminosity. The solid line represents the We first calculate predicted AGN luminosities using typical relation for Seyfert 2 galaxies (i.e., Compton-thin ob- scured AGNs) found by Liu et al.(2014). The gray shaded the [O IV] luminosities as an indicator of the AGN area shows its 1σ dispersion. Symbols and colors are the emission. Liu et al.(2014) present the L2−10–L[O IV] same as in Figure3. The arrows show the 3 σ upper limits relation using the sample of total 130 unobscured and when the [O IV] emission lines are not detected. Compton-thin obscured AGNs, including a subsample of Swift/BAT AGNs (Weaver et al. 2010). An [O IV] luminosity (mainly radiated from the NLR) relative to sample. In fact, the X-ray luminosities relative to the a bolometric AGN luminosity depends on torus covering [O IV] ones are typically smaller than the relation for factor (e.g., Yamada et al. 2019). On the other hand, obscured AGNs reported by Liu et al.(2014). Thus, es- this relation should be affected by the X-ray weakness of timates of absorption-corrected X-ray luminosities from the AGNs in U/LIRGs. Figure 14 illustrates the relation the [O IV] luminosities using the Liu et al.(2014) rela- between [O IV] and absorption-corrected 2–10 keV lu- tion should be regarded as upper limits. minosities among the hard X-ray detected AGNs in our 48 Yamada et al.

Next, we calculate 3σ upper limits of the absorption- corrected X-ray luminosities from the NuSTAR net count rates in the 8–24 keV band. To convert the count 43 rates listed in Table4 into the X-ray luminosities, we uti- lize the same AGN model as described in Section 4.2.1 by 42

ignoring the scattered and other additional components. 2 s 5 . We assume a photon index of 1.8, a torus angular width b 0 o 41 ◦ ◦ LoS 23 −2 L of 20 , and inclinations of 60 (for NH = 10 cm ) g o

◦ LoS 24 24.5 −2 l Mineo+12(XRB) and 80 (for NH = 10 and 10 cm ). The ob- Stage-A(Early) 40 tained upper limits are listed in Table 12. Stage-B(Early) Stage-C(Late) According to these upper limits, we find that eight Stage-D(Late) 39 Stage-N sources might have X-ray luminosities larger than SB or HX nondet. 43 −1 10 erg s . The multiwavelength results support that 0 1 2 3 most of them show AGN signals based on the WISE log(SFR) W1–W2 color and EW of the 6.2 µm polycyclic aro- matic hydrocarbon (PAH) emission (see AppendixB).

Among them, IRAS F14378–3651 is the only candidate 43 hosting an AGN with Chandra observations (Iwasawa et al. 2011a; Torres-Alb`aet al. 2018, and see also Ta- 42 ble B1). The inferred small fraction of AGNs in the 0 1 hard X-ray undetected sources (≤8 out of 45) is consis- s b 2 o 41 tent with their small NuSTAR band ratios as reported L g o in Section 5.1. l Mineo+12(XRB) Stage-A(Early) 40 Finally, we note that possible existence of heavily ob- Stage-B(Early) scured AGNs with N 1025 cm−2 cannot be ruled Stage-C(Late) H & Stage-D(Late) out in some cases. Among the hard X-ray undetected 39 Stage-N sources, Asmus et al.(2015) present predicted hydrogen SB or HX nondet. 0 1 2 3 column densities and absorption-corrected X-ray lumi- log(SFR) nosities for four sources by utilizing the mid-IR (high angular-resolution 12 µm continuum flux) and X-ray correlation. They classify them as an AGN/starburst composite (NGC 3690E) or uncertain AGNs (NGC 4418, 43 IRAS 15250+3609, and ESO 286-19), and suggest that 25 −2 42 the column densities need to be NH & 10 cm if they 4 are AGNs. Moreover, the X-ray weakness makes it dif- 2 s b 8 ficult to identify AGNs because the 2–10 keV luminosi- o 41 L

42 −1 g ties might be 10 erg s (assigned as low-luminosity o . l Mineo+12(XRB) Stage-A(Early) AGNs in X-rays). 40 Stage-B(Early) Stage-C(Late) Stage-D(Late) 6.3. X-ray Luminosity to SFR Relation 39 Stage-N SB or HX nondet. Comparison of observed X-ray luminosities with host 0 1 2 3 galaxy SFR could be useful to separate the contributions log(SFR) from star forming activity and AGNs. Such diagnostics Figure 15. Observed 0.5–2 keV luminosity in the 0.5–2 keV are even applicable to distant U/LIRGs whose X-ray (Top panel), 2–10 keV (Middle panel), and 8–24 keV (Bot- spectral information are limited. Figure 15 plots the ob- tom panel) bands vs. SFR. The luminosities are corrected served 0.5–2 keV, 2–10 keV, and 8–24 keV luminosities for Galactic absorption. The black solid curve represents the of the total emission against SFR for both AGNs and relation between the X-ray luminosity of the XRB emission starburst-dominant or hard X-ray undetected sources. and SFR found by Mineo et al.(2012). Here we convert the Mineo et al.(2012) present the relations between the 0.5–8 keV luminosities to the 0.5–2 keV, 2–10 keV, and 8– luminosities of the XRBs and SFRs among star-forming 24 keV ones by multiplying 0.29, 0.85, and 0.61, respectively (based on a power-law with Γ = 1.1 and E = 10 keV). galaxies. Assuming a cutoff power-law model with Γ cut The gray shaded area shows its 1σ dispersion. Symbols and = 1.1 and Ecut = 10 keV as the spectrum of the XRB colors are the same as in Figure3. The small symbols mark the starburst-dominant or 8–24 keV nondetected sources. 49

the observed X-ray luminosities with the SFRs enables us to effectively identify the AGNs in early mergers, and Mineo+12(XRB) 43 Stage-A(Early) also those in late mergers if hard X-ray (> 10 keV) fluxes Stage-B(Early) are available. Stage-C(Late) Stage-D(Late) We also examine the relation of the 0.5–2 keV luminos- 42 Stage-N ity of the unabsorbed X-ray components derived from

2 SB or HX nondet. the spectral analysis with the SFR (Figure 16). The 5 n . i b 0 41

L unabsorbed emission consists of the XRB component g o

l and, if an AGN is present, the scattered component. 40 Excluding the AGNs in early mergers and nonmergers where the scattering components significantly affect the results, we find that the estimated luminosities follow 39 the Mineo et al.(2012) relation. 0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 log(SFR) 6.4. View of SMBH-Galaxy Coevolution in Our Figure 16. 0.5–2 keV luminosity of the unabsorbed X- Sample ray component vs. SFR. The luminosities are corrected for Finally, we present a view of merger-driven coevolu- Galactic absorption. The black solid curve represents the re- tion of SMBHs and their hosts. Figure 17 plots the lation between the X-ray luminosity of the XRB component bolometric AGN luminosity L(IR) as a function of and SFR found by Mineo et al.(2012). We convert the 0.5– bol,AGN SFR for the hard X-ray detected AGNs in our sample. 8 keV luminosities to the 0.5–2 keV ones by multiplying 0.29 For the hard X-ray undetected sources, we also plot the (based on a power-law with Γ = 1.1 and Ecut = 10 keV). The gray shaded area shows its 1σ dispersion. Symbols and nominal bolometric AGN luminosities derived from the colors are the same as in Figure3. The small symbols mark [O IV] luminosities33 in Table9. In addition, we mark the starburst-dominant or 8–24 keV nondetected sources. the detections of multiphase outflows, that is, strong molecular outflows with velocities of Vout,mol ≥ 500 km s−1 (e.g., Gonz´alez-Alfonsoet al. 2017; Laha et al. 2018 emission, we find that the distribution of most of the and the references therein), ionized outflows (e.g., Rich starburst-dominant or hard X-ray undetected sources et al. 2015; Kakkad et al. 2018; Fluetsch et al. 2021), are well consistent with this relation within a ≈1σ dis- and UFOs (Mizumoto et al. 2019; Smith et al. 2019). persion (≈0.43 dex). Here, the 3σ upper limits of the Here, the SFRs are mainly obtained from the broad- 8–24 keV luminosities are converted from the NuSTAR band SED decomposition (e.g., Shangguan et al. 2019) count rates in the 8–24 keV band.32 provided in Tables8 and9. Furthermore, we plot the As noticed from Figure 15, AGN-dominant sources Palmer–Green (PG) QSOs (i.e., AGN-dominant popu- tend to show larger X-ray luminosities than those pre- lation) at z < 0.134 whose bolometric AGN luminosities dicted from the LX–SFR relation for star-forming galax- and SFRs are estimated by UV-to-IR SED decomposi- ies, indicating the contributions from the AGNs to the tion (Lyu et al. 2017). observed luminosities. These excesses are the most sig- We compare our results with the prediction from the nificant in the 8–24 keV band, whereas they become coevolution scenario (see also e.g., Ueda et al. 2018). less evident in softer bands, particularly for late merg- If the evolution of SMBHs and their hosts is exactly ers. This is because the fraction of heavily obscured simultaneous, their AGN and star-forming activities are AGNs, whose contributions to the observed fluxes below expected to follow the relation described as 10 keV are suppressed, increase with merger stage (Sec- tion 5.2). By using the observed 8–24 keV luminosities, A × M˙ BH = SFR × (1 − R), (6) most of the AGNs in U/LIRGs seems to be separatable from starburst-dominant sources. Thus, comparison of where A represents the ratio of stellar masses to black hole masses in local universe and R is the fraction of

32 To convert a 8–24 keV count rate to a flux, we assume a cut- off power-law model with Γ = 1.8 and Ecut = 10 keV for the 33 This is because the estimates from the [O IV] emission is con- starburst-dominant and hard X-ray undetected sources, which is taminated by starburst emission (Gruppioni et al. 2016), and a typical spectral shape based on the results in Section 4.2.2. thus basically present conservative upper limits of the AGN lu- This model approximately represents the summed emission from minosities for the starburst-dominant sources. the XRBs and the photoionized plasma by the AGN. 34 We only choose the PG QSOs at z < 0.1 to reduce the selection bias among PG QSOs and our U/LIRGs (z < 0.088). 50 Yamada et al.

Figure 17. IR-based bolometric AGN luminosity vs. SFR. The black dotted line represents the relation found by Trakhtenbrot & Netzer(2010) for low- z Seyfert 2s, QUEST QSOs, and high-z QSOs. The pink dashed line and shaded area show the regression line in the log–log space and its 1σ dispersion among the hard X-ray detected AGNs in mergers (stages A through D), respectively (see Equation (8)). The black solid line is the galaxy-SMBH “simultaneous evolution” lines for A = 200 (see also Ueda et al. 2018). Symbols and colors are the same as in Figure3. The small and large crosses represent the PG QSOs at 11 11 12 z < 0.1 with LIR < 10 L and LIR = 10 –10 L (LIRGs), respectively, whose LIR values are derived from the UV-to-IR SED decomposition (Lyu et al. 2017). The small symbols mark the starburst-dominant or 8–24 keV nondetected sources, whose LIR values are derived from the [O IV] luminosities. The black empty circles, empty squares, and filled points mark the detections −1 of strong molecular outflows with velocities of Vout,mol ≥ 500 km s (e.g., Gonz´alez-Alfonso et al. 2017; Laha et al. 2018 and the references therein), ionized outflows (e.g., Rich et al. 2015; Kakkad et al. 2018; Fluetsch et al. 2021), and UFOs (Mizumoto et al. 2019; Smith et al. 2019), respectively. stellar masses that are taken back to interstellar medium 2014). We thus draw the galaxy-SMBH “simultaneous (return fraction). As a representative value, we assume evolution” relation in the figure. R = 0.41 based on a Chabrier(2003) initial mass func- To quantitatively evaluate the correlation between (IR) tion. Considering that the majority of U/LIRGs should Lbol,AGN and SFR for AGNs in merging U/LIRGs, we be the progenitors of bulge-dominated galaxies (e.g., perform a linear regression analysis in log–log space Hopkins et al. 2008), we adopt A ∼ 200 for the stellar and a correlation analysis for the hard X-ray detected masses only in bulge components35 based on the latest AGNs in mergers (stages A through D).36 We employ calibration by Kormendy & Ho(2013). The mass accre- a Bayesian maximum likelihood method of Kelly(2007) tion rate onto the SMBH can be calculated by using a in which the errors in the two parameters are taken into radiative efficiency (η) as account (see also e.g., Toba et al. 2019; Setoguchi et al. 2021). The best-fitting linear function is ˙ (IR) 2 MBH = Lbol,AGN × (1 − η)/(ηc ), (7) where c is the speed of light. Here, we adopt η = 0.05, (IR) as estimated by comparison of the local SMBH mass logLbol,AGN = 0.90 logSFR + 43.11, (8) density and the AGN luminosity fraction (Ueda et al.

36 We exclude two AGNs in stage-B mergers, NGC 235 and 35 We note that even if we adopt the value for the total stellar mass Mrk 266B, because their SFRs are obtained from the total (AGN in both bulges and disks (A ∼ 400; e.g., Ueda et al. 2014, 2018), and starburst) IR luminosity (Howell et al. 2010), which are the difference of 0.3 dex does not change our conclusions. treated as upper limits. 51 and the 1σ dispersion is 0.62 dex (pink dashed line and 7. CONCLUSIONS shaded area). The correlation coefficient is r = 0.51 ± To investigate the merger-driven coevolution of 0.19, indicating a moderately tight correlation. SMBHs and their hosts, we have carried out a system- In general, the AGNs in mergers (stages A through atic X-ray spectral study of 57 local U/LIRGs (con- D) roughly follow the simultaneous evolution line with taining 84 individual galaxies) observed with NuSTAR a scatter of ∼1 dex. It is also notable that later and/or Swift/BAT. Combining available soft X-ray data mergers tend to show high SFRs and high bolometric taken with Chandra, XMM-Newton, Suzaku, and/or AGN luminosities. These results support the simplest Swift/XRT, we have identified 40 hard X-ray detected merger-driven coevolution picture where the galaxies AGNs, for which we have constrained their torus pa- and SMBHs evolve from left-bottom to right-top along rameters with the latest X-ray clumpy torus model the simultaneous evolution line after being triggered by (XCLUMPY; Tanimoto et al. 2019). Our sample con- mergers. Note that there is a group of stage-D merg- sists of two unobscured AGNs, 21 obscured AGNs, 16 1.5 −1 ers with relatively small SFRs (∼10 M yr ) and CT AGNs, one jet-dominant AGN, and 44 starburst- (IR) 44 −1 low AGN luminosities (Lbol,AGN ∼ 10 erg s ), which dominant or hard X-ray undetected sources. We list may be gas poor mergers or minor mergers, as discussed below the main conclusions from our research: in Section 5.3.4(Blecha et al. 2018). The starburst- dominant or hard X-ray undetected sources are located 1. Among the AGNs at z < 0.03, for which sample far below the simultaneous evolution line. They might biases are minimized, we find that the CT AGN +14 be in an earlier phase of U/LIRGs hosting luminous fraction in late mergers (fCT = 64−15%) is larger +12 AGNs before intense mass accretion onto the SMBHs than in early mergers (fCT = 24−10%), consistent is triggered. with the trend reported by Ricci et al.(2017a). The black dotted line represents the empirical rela- 2. We have complied the IR-based bolometric AGN tion by Trakhtenbrot & Netzer(2010) for low- z Seyfert luminosities (L(IR) ) and black hole masses in 2 galaxies (Netzer 2009), QUEST QSOs (Schweitzer bol,AGN the literature derived by various methods, and et al. 2006; Netzer et al. 2007), and high-z QSOs (e.g., adopt their averaged values for each source as Lutz et al. 2008). As expected the PG QSOs at z < 0.1 the best estimates. For the hard X-ray detected follow this relation. Assuming the evolutionary scenario AGNs, we find that their bolometric luminosities that star formation occurs first and an AGN-dominant and Eddington ratios (λ ) increase with merger phase follows later (e.g., Sanders et al. 1988), these Edd stage. The bolometric AGN luminosities in late should be the descendants of the ULIRGs that are mergers cover a wide range of L(IR) ∼ 1043.5– in the peak phase of starburst activities. The most bol,AGN 46.5 −1 luminous AGNs in IRAS F05189–2524 and Mrk 231 10 erg s , which is consistent with recent nu- (IR) 46 −1 merical simulations of gas-rich and gas-poor merg- (Lbol ∼ 10 erg s ) have relatively small column LoS 23 −2 ers. densities of NH . 10 cm , supporting that they are in an evolutionary stage between the other stage-D 3. The bolometric-to-X-ray luminosity correction U/LIRGs (hosting CT AGNs) and PG QSOs (hosting factors (κbol,X) of the AGNs in late mergers show a unobscured AGNs; Teng & Veilleux 2010). It is also systematic excess by a factor of 10–100 compared noteworthy that (likely) AGN-driven powerful molecu- with the κbol,X–λEdd relation obtained for normal lar outflows are ubiquitous in stage-D mergers with high AGNs, i.e., their SEDs are X-ray weak. SFRs and high bolometric AGN luminosities. Such co- existence of massive outflows and intense starbursts 4. Molecular outflows are detected from 10 out of has been reported among 136 outflowing ULIRGs with the 12 late (stage-D) mergers hosting hard X-ray [O III] detections by Chen et al.(2020). These results detected AGNs. The outflow velocities are cor- are quantitatively consistent with a standard AGN feed- related with both bolometric correction and Ed- back scenario where the AGN-driven outflows quench dington ratio, supporting the AGN origin for the star formation in the host and eventually luminous outflows. The X-ray weakness is likely associated ULIRGs transit to unabsorbed QSOs (e.g., Di Matteo with AGN-driven strong outflows. et al. 2005; Hopkins et al. 2008). It is, however, still 5. The AGNs with λ 0.5 in late mergers (IRAS unclear how efficiently these outflows could affect star Edd & F05189–2524, IRAS F08572+3915, and Mrk 231) formation in the host galaxy, for which further studies are located within the forbidden region of the N – are required. H λEdd diagram. This suggests that the obscuration may be caused by dusty in/outflows. Furthermore, 52 Yamada et al.

IRAS F05189–2524 and Mrk 231 show larger torus stage-D U/LIRGs (hosting CT AGNs) and PG (22) covering factors (CT ∼ 0.6) as estimated with QSOs (hosting unobscured AGNs; Teng & Veilleux XCLUMPY, than the predicted values for nor- 2010). AGN-driven powerful molecular outflows mal AGNs at similar Eddington ratios. We infer are ubiquitous in late mergers with high SFRs and that the presence of torus-scale in/outflows and/or high bolometric AGN luminosities, consistent with host-galaxy scale material enhances the fraction of a standard AGN feedback scenario. CT AGNs in late mergers. The authors first thank the anonymous referee for a 6. To comprehensively explain these results, we have careful reading of the manuscript and very helpful com- presented a unified view of AGNs in late mergers ments. S.Y. as well thanks Misaki Mizumoto for fruitful (Figure 13). Under the presence of chaotic quasi- discussion and comments. We acknowledge financial spherical inflows in late mergers, the densities and support from the Grant-in-Aid for Scientific Research covering factors of the failed winds launched from 19J22216 (S.Y.); 17K05384 and 20H01946 (Y.U.); the inner disk are enhanced. Then, these en- 20J00119 (A.T.); 21K03632 (M.I.); and 18J01050 and hanced failed winds more efficiently block X-rays 19K14759 (Y.T.). Y.T. acknowledges support from the from the central regions, making the AGN SEDs Ministry of Science and Technology of Taiwan (MOST apparently X-ray weaker compared with normal 105-2112-M-001-029-MY3). This work is also supported AGNs. Thanks to the attenuation of X-rays, UV- by the Fondecyt Iniciacion grant 11190831 (C.R.). driven winds (UFOs) can be more easily launched at larger radii in AGNs. Thus, this scenario also This work makes use of data obtained the NuSTAR explains the reason why the AGN-driven winds (in Data Analysis Software (NuSTARDAS) jointly devel- the forms of UFOs, ionized winds, and molecular oped by the ASI Science Data Center (ASDC, Italy) outflows) are more developed in late mergers than and the California Institute of Technology (USA). This in nonmerging systems. A part of inflowing mate- publication makes use of data obtained with Chandra, rial may be picked up to become radiation-driven supported by the Chandra X-ray Observatory Center at dusty outflows at high Eddington ratios. the Smithsonian Astrophysical Observatory, and with XMM-Newton, an ESA science mission with instru- 7. We evaluate the upper limits of AGN luminosities ments and contributions directly funded by ESA Mem- for the starburst-dominant and hard X-ray unde- ber States and NASA. This study makes use of data tected sources by utilizing the [O IV] luminosities obtained from the Suzaku satellite, a collaborative mis- or the NuSTAR count rates in the 8–24 keV band. sion between the space agencies of Japan (JAXA) and We find few AGN candidates among the 44 galax- the USA (NASA). The scientific results reported in this ies. article are based on observations made by UK Swift Sci- 8. We have examined the relation of observed X-ray ence Data Centre at the University of Leicester. This luminosities against SFR for the AGN-dominant research makes use of the SIMBAD database, operated and starburst-dominant U/LIRGs. We find that at CDS, Strasbourg, France (Wenger et al. 2000), and comparison of the observed X-ray luminosities the Aladin sky atlas, developed at CDS, Strasbourg Ob- with the SFRs enables us to effectively identify servatory, France (Bonnarel et al. 2000; Boch & Fer- the AGNs in early mergers, and also those in late nique 2014). Also, this research makes use of data mergers if hard X-ray (> 10 keV) fluxes are avail- from the NASA/IPAC Extragalactic Database (NED) able. and NASA/IPAC (IRSA), op- erated by JPL/California Institute of Technology under 9. Finally, we present a view of merger-driven coevo- contract with the National Aeronautics and Space Ad- (IR) ministration. lution of SMBHs and their hosts in the Lbol,AGN– SFR diagram (Figure 17). Our AGNs seem to roughly follow the “simultaneous evolution line” Facilities: NuSTAR, Chandra, XMM-Newton, from left-bottom to right-top with merger stage, Suzaku, Swift. supporting the merger-driven coevolution picture. The most luminous AGNs in IRAS F05189–2524 Software: XCLUMPY (Tanimoto et al. 2019), HEA- and Mrk 231 have relatively small column den- soft (v6.25), XSPEC(v12.10.1; Arnaud 1996), NuSTAR- LoS 23 −2 sities of NH . 10 cm , implying that they DAS(v1.8.0), CIAO(v4.11), SAS (v17.0.0; Gabriel et al. are in an evolutionary stage between the other 2004). 53

APPENDIX

Lbol: [O IV] MBH: M*

Lbol: AGN fraction 9 MBH: M- *

46 Lbol: IR SED MBH: Lbulge

] Lbol: IRS spectra M : others ] BH s s d d o o h t 45 h t 8 e e m

m

4 [ 4

[

N

44 ) G H A B , ) l 7 R o I M ( b ( L g g o l

o 43 l

6 42 42 43 44 45 46 6 7 8 9 (IR) log(MBH) [average] logLbol, AGN [average]

Figure A1. Comparison among the bolometric AGN lu- Figure A2. Comparison among the black hole masses de- minosities derived from different methods: the [O IV] lumi- rived from different methods: the stellar mass (blue square; nosity (blue square; e.g., Gruppioni et al. 2016), the bolo- e.g., Reines & Volonteri 2015; Shangguan et al. 2019), the metric AGN fraction (green triangle; e.g., D´ıaz-Santos et al. M–σ∗ relation (green triangle; e.g., G¨ultekinet al. 2009), 2017), the 1–500 µm SED decomposition and Spitzer/IRS the photometric bulge luminosity (red diamond; e.g., Win- spectral fitting (red diamond and yellow star, respectively; ter et al. 2009; Veilleux et al. 2009b; Haan et al. 2011), and Alonso-Herrero et al. 2012; Shangguan et al. 2019). The the other various methods, such as the flux density of old black dashed line shows the 1:1 relation between the individ- stellar emission at 2 µm and so on (yellow star; e.g., Ca- ual estimates (y-axis) and their averages (x-axis). ramete & Biermann 2010). The black dashed line shows the 1:1 relation between individual estimates (y-axis) and their averages (x-axis). A. COMPARISON AMONG DIFFERENT (IR) MEASUREMENTS OF LBOL,AGN AND MBH that the measurements from dynamical stellar mass and We investigate if there are systematic trends among velocity dispersion (blue squares and green triangles) are different measurements for bolometric AGN luminosi- smaller than those from bulge luminosities and other ties and black hole masses (Section 5.3). Figure A1 methods (red diamonds and yellow stars). A typical shows the comparison among bolometric AGN luminosi- scatter is ±0.3–0.5 dex when we adopt the averaged ties derived from different methods: the [O IV] luminos- value. We discuss possible reasons for the systematic dif- ity, bolometric AGN fraction, the 1–500 µm SED de- ferences in Section 5.3.3 (see also Veilleux et al. 2009b). composition and Spitzer/IRS spectral fitting. The aver- Figure A3 represents the relation between the aver- aged values obtained with these methods in our sample aged bolometric AGN luminosity and the four individual is logL(IR) = 44.80 (22 AGNs), 44.59 (29 AGNs), bol,AGN black hole measurements for each AGN. It is notable 44.86 (20 AGNs), and 44.32 (18 AGNs), respectively. A that the systematic differences seem to depend neither typical scatter is about ±0.27 dex when we adopt the av- the bolometric AGN luminosity nor Eddington ratio. eraged value of the four measurements for an individual object, as noted in Section 5.3.1. In Figure A2, we compare the black hole masses de- B. NOTES ON INDIVIDUAL OBJECTS rived from the stellar mass, the M–σ∗ relation, the pho- tometric bulge luminosity, and the other methods (e.g., In this section, we present the basic characteristics the flux density of 2 µm old stellar emission). We find of the individual objects in our sample (also refer to Appendix A in Ricci et al. 2017a for a subsample). We 54 Yamada et al.

(viii) Optical spectroscopic classification on the BPT diagram (i.e., [O III]/Hβ and [Ne III]/[O II] ratios, Bald- win et al. 1981; Kewley et al. 2006). Sy stands for Edd=1 9 Edd=0.1 Seyfert with subcategories 1, 1.5, 1.8 and 2. L stands Edd=0.01

MBH: M* for LINERs. Cp stands for objects between star-forming

MBH: M- * ] and AGN regions in the BPT (e.g., Yuan et al. 2010).

s MBH: Lbulge d MBH: others HII stands for HII regions. Reference is given in each o h

t 8 case. e (ix) X-ray AGN signatures based on Chandra obser- m

4 vations (Iwasawa et al. 2011a; Torres-Alb`aet al. 2018): [

) color between the 0.5–2 keV and 2–7 keV bands, de- H B 7 tection of the 6.4 keV line, and continuum absorption M (

g features. o l In TableB1, we also provide X-ray classification based on our broadband X-ray spectral analysis for the hard 6 X-ray detected AGNs (unobscured AGN for NH < 22 −2 22 24 −2 10 cm , obscured AGN for NH = 10 –10 cm , 42 43 44 45 46 24 −2 and CT AGN for NH ≥ 10 cm ). logL(IR) [average] bol, AGN Finally, we summarize the basic properties of the in- Figure A3. Relation between the averaged bolometric AGN dividual sources and discuss the presence or absence of luminosity and the individual black hole masses derived from AGNs on the basis of the broadband X-ray spectral anal- the four methods. Symbols are as in Figure A2. The black ysis and multiwavelength results. solid, dashed, and dotted lines represent the relations ex- pected for three different Eddington ratios (λEdd = 1, 0.1, 1. IRAS F00085–1223 (NGC 34): and 0.01, respectively). This is a LIRG with a single nucleus, assigned as a stage-D merger. We identify the source as the hard X-ray detected AGN. The XMM- also compare the results of our X-ray spectral analysis Newton studies indicate that NGC 34 hosts an with previous studies. We confirm that the hard X-ray obscured AGN (Guainazzi et al. 2005; Brightman detected AGNs tend to show AGN signs based on the & Nandra 2011a), and the recent NuSTAR stud- following nine diagnostics as summarized in Table B1: ies estimate its absorption column density to be (i) WISE color of W1−W2 ≥ 0.8 (i.e., [3.4]−[4.6] ≥ N ∼ 5 × 1023 cm−2 (Ricci et al. 2017a; Mingozzi 0.8 in magnitude) (Stern et al. 2012). We note H et al. 2018). This is consistent with our value that this diagnostic is not applicable for low-luminosity of N = (5.0 ± 1.0) × 1023 cm−2 by using the AGNs in hosts with strong starburst activities (e.g., H NuSTAR, Chandra, and XMM-Newton data. The Griffith et al. 2011; Hainline et al. 2016). absorption-corrected 2–10 keV luminosity we ob- (ii) Near-IR 2.5–5 µm continuum slope of Γ > 2.5−5 tain is logL = 41.90 ± 0.10. 1.0 (Imanishi et al. 2010), which is an indicator of an 2−10 obscured AGN (Risaliti et al. 2006; Imanishi et al. 2008), 2. IRAS F00163–1039 N/S (MCG–02-01-052 and (iii) Optical depths of 3.1 µm ice-covered dust and/or MCG–02-01-051): 3.4 µm bare carbonaceous dust absorption features These two sources are in a stage-B merger, and (τ > 0.3 and/or τ > 0.2). These are indicators of 3.1 3.4 their separation is 5600. 1 (a projected distance of an obscured AGN with a centrally concentrated energy 30.7 kpc). While the southern object MCG–02- source (Imanishi et al. 2010). 01-051 (= ) is a LIRG, the northern ob- (iv)–(v) EWs of the 3.3 µm and 6.2 µm PAH fea- ject MCG–02-01-052 has a lower IR luminosity of tures (EW < 40 nm, Imanishi et al. 2008, 2010; 3.3 logL /L = 10.36 (Ricci et al. 2017a). Although EW < 27 nm, Stierwalt et al. 2013). IR 6.2 their hard X-ray emission is not detected with (vi) Detection of the mid-IR [Ne V] 14.32 µm line (e.g., NuSTAR (see also Ricci et al. 2017a), Chandra Inami et al. 2013). detects X-ray emission from both nuclei. The best- (vii) Radio spectral index maps (α-maps) at 1.49 GHz fit photon indices obtained with the starburst- and 8.44 GHz, which can be used to find AGN emission dominant model are Γ ∼ 1.5 for MCG–02-01-052 from central kpc regions (Vardoulaki et al. 2015). and Γ ∼ 1.7 for MCG–02-01-051. 55

Table B1. Summary of the AGN Signatures Obtained by Multiwavelength Observations

Object Name W1–W2 Γ2.5−5 τ3.1,3.4 PAH3.3 PAH6.2 [Ne V] Radio Opt. C–GOALS This work Ref. (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12)

NGC 34 n n n n n n Y Sy2 Y(A) Obs 1 MCG–02-01-052 n ············ n ··· HII ··· n 1 MCG–02-01-051 n n ··· n n n ··· HII ··· n 1 ESO 350-38 Y(1.336) ········· Y(0.15) n ··· HII n n 1 NGC 232 n n n Y n n ··· Cp n n 1,2 NGC 235 n ········· Y(0.16) Y ··· Sy2 ··· Obs 3 MCG+12-02-001 n ········· n n ··· Cp ··· CT 4 MCG+12-02-001 NED01 ··············· n ········· n ··· IC 1623A Y(1.240;u) n ··· n n n Y(u) HII ··· n 1 IC 1623B Y(1.240;u) Y Y Y ··· n Y(u) HII ··· n 1 NGC 833 n ············ n ··· L n Obs 5 NGC 835 n ········· n n ··· Sy2 n Obs 5 NGC 838 n ········· n n ··· L n n 6 NGC 839 n ········· n n ··· L n n 6 NGC 1068 Y(1.125) ············ Y ··· Sy2 Y(L) CT 1,a UGC 2608 Y(1.282) ········· Y(0.20) Y ··· Sy2 ··· CT 3,b UGC 2612 n ········· Y(0.25) n ········· n ··· NGC 1275 Y(1.006) ········· Y(0.02) n ··· Sy1.5 ··· Jet 3,c NGC 1365 n ········· Y(0.13) Y ··· Sy1.8 Y(CLA) Obs 7,d ESO 203-1 Y(1.143) ········· Y(0.03) n ······ n n? ··· CGCG 468-002W n ········· Y(0.12) Y ··· Sy2 ··· Obs 8 CGCG 468-002E n ········· n n ········· n ··· IRAS F05189–2524 Y(1.125) ··· n Y Y(0.03) Y n Sy2 Y(CL) Obs 1 IRAS F06076–2139 n ········· n n ··· Sy? Y(C) Obs 9 2MASS 06094601–2140312 ··············· n ··· HII n n 9 NGC 2623 n n Y Y Y(0.27) Y Y Cp Y(C) Obs 10 ESO 060-IG016 West ··············· Y(u) ······ n n ··· ESO 060-IG016 East ············ Y(0.11) Y(u) ······ Y(C) Obs ··· IRAS F08572+3915 Y(2.313) ··· Y Y Y(0.03) n Y Sy2 Y(C) Obs 1 UGC 5101 Y(1.697) ··· Y Y Y(0.13) Y Y Sy2 Y(CL) Obs 1 MCG+08-18-012 n ············ n ······ n n ··· MCG+08-18-013 n n ··· n ··· n ··· Cp n n 1 MCG–01-26-013 n ············ n ······ n n ··· NGC 3110 n n n n n n ··· HII n n 1 ESO 374-IG032 Y(2.534) ········· Y(0.03) n ··· HII n n 11 NGC 3256 n ········· n n ··· HII n n 12 IRAS F10565+2448 n ········· n n n HII n n 13 NGC 3690 West ··· Y(u) n Y(u) Y(0.12) n Y Sy2 Y(L) CT 14 NGC 3690 East ··· Y(u) n Y(u) n n Y L n n 14 ESO 440-58 ············ n n ··· Cp n n 11 MCG–05-29-017 n ········· n n ··· Cp n n 11 IRAS F12112+0305 Y(0.802) n ··· n n n Y Sy2 n n? 1 NGC 4418 Y(1.258) n n Y Y(0.02) n ··· Sy2 n n 5 MCG+00-32-013 n ············ n ········· n ··· Mrk 231 Y(1.097) n ··· Y Y(0.01) n Y Sy1 Y(CL) Obs 1 NGC 4922S ··············· n ··· Sy2(u) n n 1 NGC 4922N ············ Y(0.16) Y ··· Sy2(u) Y(A) Obs 1 IC 860 n n ··· Y n n ··· Sy? Y(C) n 4 IRAS 13120–5453 ············ n n ··· Sy2 Y(C) CT 5 NGC 5104 n n ··· Y n n ··· L ··· n 1,13 MCG–03-34-064 Y(1.431) Y ··· Y Y(0.01) Y ··· Cp/Sy2 Y(LA) Obs 1,7

Table B1 continued 56 Yamada et al. Table B1 (continued)

Object Name W1–W2 Γ2.5−5 τ3.1,3.4 PAH3.3 PAH6.2 [Ne V] Radio Opt. C–GOALS This work Ref. (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12)

NGC 5135 n n ··· Y n Y ··· Sy2 Y(L) CT 1,b Mrk 266B n n n n n Y Y Cp/Sy2 Y(L) CT 1,7,e Mrk 266A n ········· n n n Sy2 Y(A) Obs 1,e Mrk 273 Y(1.182) n n n Y(0.12) Y Y Sy2 Y(CL) Obs 1 IRAS F14348–1447 Y(1.002) Y Y n Y(0.25) n Y Cp Y(C) CT 1 IRAS F14378–3651 Y(0.871) ········· n n Y Sy2 Y(C) Y? 15 IC 4518A Y(1.228) ············ Y† ··· Sy2 ··· Obs 16 IC 4518B ··············· n† ········· n ··· IRAS F15250+3608 ··· Y n n Y(0.03) n Y Cp n n? 1 Arp 220W n n n n Y(0.17;u) n Y(u) Cp(u) n CT 1 Arp 220E n n n n Y(0.17;u) n Y(u) Cp(u) n n 1 NGC 6240S n ········· n Y(u) ··· Cp(u) Y(L;u) CT 1,f NGC 6240N n ········· n Y(u) ··· Cp(u) Y(L;u) CT 1,f NGC 6285 n n ··· n n n ··· Cp n n 1 NGC 6286 n n n n n n ··· Cp Y(A) CT 1 IRAS F17138–1017 n ········· n n ··· Cp Y(C) Obs 1 IRAS F18293–3413 n ········· n n ··· HII n n 1 IRAS F19297–0406 n ········· n n ··· Cp n n? 1 NGC 6907 n ········· n n ········· n ··· NGC 6908 n ············ n ········· n ··· NGC 6921 n ············ n ··· L ··· CT 17 MCG+04-48-002 n ········· n Y ··· HII ··· Obs 17,18 II Zw 096 ············ n n ······ n n? ··· IRAS F20550+1655 SE Y(0.997) ········· Y(0.27) n ······ n n? ··· ESO 286-19 Y(1.441) Y n n Y(0.10) n ··· HII n n? 1,12 NGC 7130 n n ··· n n Y ··· Sy2 Y(LA) CT 1 NGC 7469 n n ··· Y Y(0.23) Y ··· Sy1 ··· Unobs 1,g IC 5283 n ············ n ········· n ··· ESO 148-2 Y(1.077) n ··· n n Y ··· Cp Y(C) CT 19 NGC 7591 n ········· n n ··· Sy2 n n 1 NGC 7674 Y(1.160) Y ··· Y Y(0.02) Y ··· Sy2 ··· Obs 1 MCG+01-59-081 n ············ n ········· n ··· NGC 7679 n ········· n Y ··· Sy2 ··· Unobs 1 NGC 7682 n ············ n ··· Sy2 ··· Obs 20

Note—Columns: (1) object name; (2–8) multiwavelength AGN signatures based on WISE color in NASA/IPAC Infrared Science Archive (IRSA), 2.5–5 µm continuum slope, 3.1 µm and 3.4 µm absorption feature (Imanishi et al. 2010), EW of the 3.3 µm (Imanishi et al. 2008, 2010) and 6.2 µm PAH emission (Stierwalt et al. 2013), [Ne V] 14.32 µm line (Inami et al. 2013), and radio spectral index maps (Vardoulaki et al. 2015). The criteria for the presence of an AGN is described in the text; (9) classification based on the optical spectroscopy and the BPT diagram. Sy stands for Seyfert with subcategories 1, 1.5, 1.8 and 2. L stands for LINERs. Cp stands for AGN/starburst composite (e.g., Yuan et al. 2010). HII stands for HII regions; (10) AGN selection criteria in the C–GOALS sample (Iwasawa et al. 2011a; Torres-Alb`aet al. 2018); the 0.5–2 keV to 2–7 keV color (C), detection of 6.4 keV line (L), and absorbed AGN feature (A); (11) X-ray classification based on this work for hard X-ray detected AGNs (Unobs = unobscured AGN, Obs = obscured AGN, CT = CT AGN, Jet = a jet-dominant AGN) and for hard X-ray undetected sources (Y? = good candidate hosting an AGN based on the 8–24 keV upper limits, n? = object with a possible AGN based on the 8–24 keV upper limits, and n = object with no sign of the AGN emission in the hard X-ray band, see also Section 6.2); (12) references of the optical classification in Column (9) marked as “1–20”, and the previous NuSTAR results for some AGNs in Column (11) marked as “a–g”. References: (1) Yuan et al.(2010); (2) L´opez-Cob´aet al.(2020); (3) V´eron-Cetty & V´eron(2006); (4) Alonso-Herrero et al.(2009); (5) V´eron- Cetty & V´eron(2010); (6) Vogt et al.(2013); (7) Brightman & Nandra(2011b); (8) Alonso-Herrero et al.(2013); (9) Arribas et al.(2008); (10) L´ıpariet al.(2004); (11) Rich et al.(2015); (12) L´ıpariet al.(2000); (13) Veilleux et al.(1995); (14) Garc´ıa-Mar´ınet al.(2006); (15) Duc et al. (1997); (16) Masetti et al.(2008); (17) Koss et al.(2016); (18) Masetti et al.(2006); (19) L´ıpariet al.(2003); (20) Huchra & Burg(1992); (a) Bauer et al.(2015); (b) Yamada et al.(2020); (c) Rani et al.(2018); (d) Rivers et al.(2015); (e) Iwasawa et al.(2020); (f) Puccetti et al.(2016); (g) Ogawa et al.(2021).

† The results of [Ne V] detection on IC 4518A/IC 4518B are referred from Pereira-Santaella et al.(2010). 57

3. IRAS F00344–3349 (ESO 350-38): analysis, it is 2.98σ and 3.37σ in the 8–24 keV The LIRG ESO 350-38 is a stage-C merger com- and 10–40 keV bands, respectively. By combin- posed of three main star-forming condensations ing the Chandra observations, we analyze the 0.2– (Kunth et al. 2003; Atek et al. 2008). Among 40 keV spectra and suggest the presence of a CT 24 −2 them, the eastern and western knots whose sep- AGN with NH > 4.3 × 10 cm . The estimated aration is 500. 2 (2.2 kpc) are clearly resolved as X- absorption-corrected X-ray luminosity is logL2−10 +0.33 ray sources with Chandra (e.g., Torres-Alb`aet al. = 41.75−0.08, classifying it as a low-luminosity 2018). NuSTAR detects only soft X-ray emis- AGN. The large fraction of unabsorbed soft X- sion below ∼10 keV. Combining the NuSTAR ray emission (fbin & 9%) implies that the star- and Chandra data, we constrain the photon in- burst emission seems to be dominant in soft X- rays, in agreement with the optical classification dex and cutoff energy to be Γ ≤ 1.62 and Ecut = +3.4 of the AGN/starburst composite and with no clear 6.6−1.5 keV, respectively, supporting that this is a starburst-dominant galaxy. AGN signs from the other multiwavelength diag- nostics. 4. IRAS F00402–2349 W/E (NGC 232 and NGC 6. IRAS F01053–1746 W/E (IC 1623A and IC 235): 1623B): This LIRG in merger stage-B is composed of two The LIRG IC 1623 (= VV 114) is a stage-C merger nuclei (NGC 232 and NGC 235) with a separa- consisting of two nuclei with a separation of 1500. 7 tion of 12000. 8 (54.7 kpc). We identify NGC 235 (6.4 kpc). The eastern object (IC 1623B) is much as the hard X-ray detected AGN. The fractions brighter than the western source (IC 1623A) in of the Spitzer/MIPS 24 µm luminosities are 68% the Spitzer/IRAC bands. Whereas, the Chan- and 32% for the western (NGC 232) and east- dra results by Grimes et al.(2006) show that ern (NGC 235) objects, respectively (Inami et al. IC 1623A is much brighter than IC 1623B in X- 2013). NGC 235 has an X-ray bright AGN in rays. IC 1623A is also very luminous in the UV the Swift/BAT 105-month catalog, and the hy- and optical, with many star clusters detected in drogen column density is estimated to be N ∼ H HST images (Cortijo-Ferrero et al. 2017b) and in 3 × 1023 cm−2 by using the Swift/BAT and XRT soft X-ray images (Chandra and XMM-Newton). observations (Ricci et al. 2017c). Combining the Grimes et al.(2006) imply the possible presence Chandra and Suzaku data with the Swift/BAT of a low-luminosity AGN in IC 1623B (N ∼ spectrum, we find that the column density varies H 1.5 × 1022 cm−2), although its contribution to from (2.9 ± 0.2) × 1023 cm−2 (Chandra) to N = H the total soft X-ray flux of the system is small. (5.1+0.8) × 1023 cm−2 (Suzaku and Swift/BAT). −0.6 We cannot reproduce the broadband spectra of The estimated absorption-corrected X-ray lumi- the system observed with NuSTAR, Chandra, and nosity is logL = 43.28+0.18. For NGC 232, 2−10 −0.16 XMM-Newton by the AGN model, due to a cut- only the Chandra spectrum is obtained, and the off feature at E = 8.1+0.8 keV. Thus, we treat starburst-dominant model yields the best-fit pho- cut −0.7 them as non AGNs in this paper. The starburst- ton index of Γ ∼ 1.6. dominant model yields Γ ≤ 1.51. 5. IRAS F00506+7248 (MCG+12-02-001): 7. IRAS F02071–1023 W2/W/E/S (NGC 833, NGC This system is a stage-C merger composed of four 835, NGC 838 and NGC 839): galaxies; the northern source (MCG+12-02-001a), The system IRAS F02071–1023 (= HCG 16 or the western source (MCG+12-02-001 NED01), Arp 318) is a stage-A merger with seven member and the eastern interacting pair (MCG+12-02- galaxies, including the central four spiral galax- 00 001) with a separation of 0. 9 (0.3 kpc; Ricci et al. ies (Hickson 1982). With the Chandra obser- 2017a). The eastern pair is assigned as a LIRG, vations, O’Sullivan et al.(2014) detect obscured which is the brightest source of this system in the AGNs in the pair of NGC 833 and NGC 835 sep- IRAC 1–4 (3.6, 4.5, 5.8, and 8.0 µm) images. We arated by 5600. 4 (15.3 kpc), whereas they conclude identify this pair (MCG+12-02-001) as the hard that NGC 838 and NGC 839, separated by 14800. 8 X-ray detected AGN. (39.1 kpc), are starburst-dominant sources. Bit- Ricci et al.(2017a) report that the detection sig- sakis et al.(2014) estimate their total IR lumi- nificance with NuSTAR in the 3–10 keV and 10– nosities by the UV-to-submillimeter SED decom- 24 keV bands are <3σ in this system. In our position, and find that only NGC 838 is a LIRG. 58 Yamada et al.

We identify both NGC 833 and NGC 835 as the (2020) perform a broadband spectral analysis of hard X-ray detected AGNs. UGC 2608 with XCLUMPY and identify a heavily +7.0 24 −2 Oda et al.(2018) carry out a detailed X-ray obscured AGN (NH = 5.4−3.1 × 10 cm ) with an absorption-corrected luminosity of logL2−10 = study of this system using NuSTAR, Chandra, +0.19 and XMM-Newton, detecting the obscured AGNs 43.59−0.25. For UGC 2612, no X-rays are detected 23 −2 with NuSTAR, Chandra, or XMM-Newton. The with NH ∼ 3 × 10 cm in both NGC 833 3σ upper limit of the AGN luminosity in UGC and NGC 835. They also report an increase (lim) of the line-of-sight column density in NGC 835 2612 is logL2−10 < 42.89, assuming logNH ≤ 24.5. from 2000 (XMM-Newton) to 2013/2015 (Chan- 10. IRAS F03164+4119 (NGC 1275): dra/NuSTAR; ∼5 ×1023 cm−2). We find, how- ever, that our AGN model with XCLUMPY can The radio galaxy NGC 1275 is a nonmerging reproduce the variability by a change of the (stage-N) LIRG in the Perseus cluster. Fukazawa absorption-corrected luminosity rather than that et al.(2018) find correlated long-term variability Time +0.19 between X-ray (Suzaku/XIS and Swift/XRT) and of the column density (C = 1.95−0.21 for Time +0.02 GeV -ray (Fermi/LAT) fluxes, indicating a Chandra; and C = 0.11−0.01 for XMM- Newton). We estimate the column densities to significant jet contribution to the X-ray emission. 23 −2 be NH = (2.6 ± 0.1) ×10 cm and NH = The Hitomi observation reveals that the Fe Kα line +0.1 23 −2 at 6.4 keV is emitted from a region at ∼1.6 kpc (3.0−0.2) × 10 cm , and the X-ray luminosi- +0.25 from the core, most likely a low-covering-faction ties to be logL2−10 = 41.99−0.24 and logL2−10 = +0.13 torus or a rotating molecular disk (Hitomi Collab- 42.06−0.03 for NGC 833 and NGC 835, respec- tively. NuSTAR does not detect hard X-ray emis- oration et al. 2018). By analyzing the NuSTAR sion from NGC 838 and NGC 839. Their best-fit and Swift/BAT spectra, Rani et al.(2018) suggest photon indices derived from the Chandra spectra that the hard X-ray power-law component domi- with the starburst-dominant models are Γ ≤ 1.52 nating the spectrum above 20 keV originates from +0.7 the jet. Thus, we find it difficult to constrain the (with Ecut = 4.7−0.6 keV) and Γ ≤ 1.51, respec- tively. column density and AGN luminosity of the nucleus from the broadband spectra, and discuss only the 8. IRAS F02401–0013 (NGC 1068): NuSTAR band ratio in this paper. The LIRG NGC 1068 is a possible past merger 11. IRAS F03316–3618 (NGC 1365): (Tanaka et al. 2017) categorized as a stage-N source in this work. The source has been well stud- The LIRG NGC 1365 is a stage-N object. The ied in X-rays, e.g., with Chandra (e.g., Torres-Alb`a source has an AGN showing extreme absorption et al. 2018) and NuSTAR (e.g., Marinucci et al. variability observed with e.g., Chandra (Torres- 2016). We refer to the results reported in Bauer Alb`a et al. 2018; Venturi et al. 2018), XMM- et al.(2015), who perform a spectral analysis Newton (Risaliti et al. 2005; Whewell et al. 2016), adopting a multi-component reflector model to the and NuSTAR (e.g., Walton et al. 2014a; Risaliti NuSTAR, Chandra, XMM-Newton, Suzaku, Bep- 2016). Rivers et al.(2015) study the variable ab- poSAX, and Swift/BAT spectra. They find that sorption seen in the four long-look joint observa- 25 −2 the AGN is heavily obscured (NH ∼ 10 cm ) tions of NuSTAR and XMM-Newton with a multi- with an absorption-corrected X-ray luminosity of layer absorber model. In this work, we refer to +0.07 23 −2 logL2−10 = 43.34−0.08. their averaged values of NH ∼ 1 × 10 cm and logL2−10 = 41.90 ± 0.01. 9. IRAS F03117+4151 N/S (UGC 2608 and UGC 2612): 12. IRAS F04454–4838 (ESO 203-1): Each galaxy in IRAS F03117+4151 is a stage-N This LIRG is a stage-B merger showing two nuclei source with no sign of interaction. The northern (north-east and south-west components) with a object (UGC 2608) is a LIRG, while the south- separation of 700. 5 (7.7 kpc; Haan et al. 2011). The ern object (UGC 2612) is faint in the IR (e.g., north-eastern galaxy is much brighter than south- Inami et al. 2013). Guainazzi et al.(2005) re- western source in the Spitzer/IRAC 1–4 bands. port the results of the XMM-Newton observation The Chandra (see also Iwasawa et al. 2011a) and of UGC 2608. Adding the NuSTAR and Suzaku NuSTAR observations do not detect any X-ray data to the XMM-Newton ones, Yamada et al. emission in this system. The 3σ upper limit of 59

(lim) the AGN luminosity is logL2−10 < 43.06 assuming 15. IRAS F06076–2139 N/S (IRAS F06076–2139 and logNH ≤ 24.5. 2MASS 06094601–2140312): This system is a stage-C LIRG consisting of two 13. IRAS F05054+1718 W/E (CGCG 468-002W and galaxies separated by 800. 3 (6.2 kpc). The north- CGCG 468-002E): ern source (IRAS F06076–2139) is much brighter These two stage-B merging galaxies have a sep- than southern source (2MASS 06094601–2140312) aration of 2900. 5 (10.3 kpc). The eastern source in the Spitzer/IRAC 1–4 bands. We identify IRAS (CGCG 468-002E) is a LIRG, while the west- F06076–2139 as the hard X-ray detected AGN. Us- ern source (CGCG 468-002W) is not luminous ing NuSTAR and Chandra, Privon et al.(2020) in the IR band (logLIR/L = 10.74; Ricci et al. detect X-ray emission from the obscured AGN in 23 −2 2017a). We identify CGCG 468-002E as the hard IRAS F06076–2139 with NH ∼ 6×10 cm , con- +2.4 23 −2 X-ray detected AGN. The recent study with NuS- sistent with our result (NH = 4.2−1.2 ×10 cm ). TAR and Swift/XRT observations by Ricci et al. The absorption-corrected X-ray luminosity we ob- +0.15 (2017a) reveals the presence of an AGN with NH ∼ tain is logL2−10 = 42.18−0.14. No significant X- 1.5×1022 cm−2 in CGCG 468-002E. This is consis- ray emission from 2MASS 06094601–2140312 is de- tent with our results using NuSTAR, Swift/BAT tected with NuSTAR and Chandra. 22 −2 and XRT data (NH = 1.5 ± 0.1 × 10 cm and +0.04 16. IRAS F08354+2555 (NGC 2623): logL2−10 = 42.84−0.03). Due to a contamination from the brighter eastern source, the upper limit The LIRG NGC 2623 is a stage-D merger with a of the hard X-ray flux of the western source is not single nucleus. We identify the source as the hard constrained. X-ray detected AGN. The Chandra and XMM- Newton studies suggest the presence of an ob- 14. IRAS F05189–2524: scured AGN (Maiolino et al. 2003; Evans et al. This ULIRG is a stage-D merger with a single nu- 2008; Iwasawa et al. 2011a), We detect the 8– cleus. The galaxy shows multiphase outflows de- 24 keV emission at 4.5σ level with NuSTAR. With tected as UFO (Smith et al. 2019), ionized outflow the broadband spectral analysis using the NuS- (e.g., Fluetsch et al. 2019, 2021), and molecular TAR, Chandra, and XMM-Newton data, we es- +4.5 22 −2 outflow with >500 km s−1 (e.g., Veilleux et al. timate that NH = (6.0−2.1) × 10 cm and 2013). We identify the galaxy as the hard X-ray logL2−10 = 40.90 ± 0.11. detected AGN. 17. IRAS F08520–6850 W/E (ESO 060-IG016 West The source has been well studied in X-rays by e.g., and ESO 060-IG016 East): Chandra (Ptak et al. 2003; Grimes et al. 2005; Iwasawa et al. 2011a), XMM-Newton (Imanishi & This LIRG system is a stage-B merger, composed 00 Terashima 2004; Teng & Veilleux 2010), Suzaku of two galaxies separated by 15. 4 (13.6 kpc). We (Teng et al. 2009), and NuSTAR (e.g., Teng et al. identify ESO 060-IG016 East as the hard X-ray 2015; Xu et al. 2017; Smith et al. 2019). NuSTAR detected AGN. The Chandra spectrum of ESO detects the hard X-ray emission from an obscured 060-IG016 East reveals the presence of an ob- 23 −2 AGN. Teng et al.(2015) fit the combined NuSTAR scured AGN with NH ∼ 1 × 10 cm (Iwa- and XMM-Newton spectra with a two absorber sawa et al. 2011a), whose 8–24 keV emission is 22 −2 detected with NuSTAR. Combining these obser- model (NH ∼ 5 × 10 cm covering 98% and 22 −2 vations, we constrain the column density and NH ∼ 9 × 10 cm covering 74%). With the XCLUMPY model, we confirm dramatic variabil- absorption-corrected AGN luminosity to be NH = +4.0 22 −2 +0.07 (8.4−2.9) ×10 cm and logL2−10 = 41.94−0.08, ity in absorption between Compton-thin (NH = (7.5 ± 0.1) × 1022 cm−2 for NuSTAR, Chandra, respectively. NuSTAR and Chandra detect no sig- XMM-Newton, and Swift/BAT) and CT obscura- nificant X-ray emission from ESO 060-IG016 West. tion (>2.3 ×1024 cm−2 for Suzaku), as discussed 18. IRAS F08572+3915: in Section 6.1.5. We estimate the absorption- corrected X-ray luminosity to be logL2−10 = This is a double-nucleus ULIRG (north-west and +0.01 43.42−0.02. south-east components) classified as a stage-D merger with a separation of 400. 4 (5.6 kpc; Ricci et al. 2017a). From the north-western nucleus, a 60 Yamada et al.

very deep silicate absorption and little PAH emis- is a LIRG, whereas MCG+08-18-012 is less lumi- sion are detected in the Spitzer IRS spectrum, in- nous (logLIR/L = 9.93; Ricci et al. 2017a). Both dicating the presence of a heavily obscured AGN objects are not detected wuth NuSTAR in either (e.g., Spoon et al. 2007). Ionized outflow (e.g., the 3–8 keV or 8–24 keV bands, as reported by Fluetsch et al. 2019, 2021) and molecular outflow Ricci et al.(2017a). Chandra detects X-ray emis- with >500 km s−1 (e.g., Sturm et al. 2011; Cicone sion only from MCG+08-18-013. By adopting the et al. 2014) have been discovered, whereas UFO starburst-dominant model without an apec com- is not detected under the poor statistics of the X- ponent, we obtain Γ ≤ 1.84. ray data (e.g., Mizumoto et al. 2019). We identify 21. IRAS F10015–0614 S/N (MCG–01-26-013 and IRAS F08572+3915 as the hard X-ray detected NGC 3110): AGN. IRAS F10015–0614 is a stage-A merger with two Iwasawa et al.(2011a) report the Chandra re- galaxies separated by 10800. 8 (36.5 kpc). The LIRG sults that the northwest nucleus is detected in NGC 3110 (north) is much brighter than MCG– the ∼2–4 keV band, whereas the south-eastern 01-26-013 (south) in the Spitzer/IRAC and Her- source is much fainter. The X-ray color suggests schel images (Chu et al. 2017). Ricci et al.(2017a) an obscured AGN in the northwest nucleus. Al- report that neither of them is detected with NuS- though the earlier NuSTAR observation detects TAR. They obtain photon indices of Γ = 1.8+0.6 no X-ray emission (Teng et al. 2015), we detect −0.7 for MCG–01-26-013 and Γ = 2.2+0.3 for NGC 3110 the hard X-ray emission at 3.9σ level by utiliz- −0.2 by using the Chandra and XMM-Newton spectra. ing the recent follow-up observation in 2019 (Ob- Although we fix Γ = 1.8 for MCG–01-26-013 in our sID = 50401004002; PI: C. Ricci). The large analysis, we obtain Γ = 1.8 ± 0.1 for NGC 3110; NuSTAR band ratio (BRNu ∼ 1.6) supports the the difference from Ricci et al.(2017a) is likely presence of an AGN (Section 5.1). From the comes from the inclusion of absorption (zphabs) to 0.1–20 keV spectra of NuSTAR, XMM-Newton, the soft X-ray component in Ricci et al.(2017a). and Suzaku, we estimate the absorption and We confirm the conclusion by Ricci et al.(2017a) absorption-corrected X-ray luminosity to be N = H that the X-ray spectra do not require the presence (8.5+12.9) × 1023 cm−2 and logL = 41.77+0.06, −2.8 2−10 −0.07 of AGNs in these galaxies. respectively, by assuming fbin = 10%, which may be highly uncertain. 22. IRAS F10038–3338 (ESO 374-IG032):

19. IRAS F09320+6134 (UGC 5101): This merger stage-D LIRG shows a single nucleus. It was mistakenly identified with the optical source The ULIRG UGC 5101 is a stage-D merger show- IC 2524 in the RBGS catalog; the correct counter- ing a single nucleus. We identify the source part is ESO 374-IG032 (see the Essential Notes as the hard X-ray detected AGN. Ricci et al. in NED). Chandra detects a faint X-ray source (2015) detect a CT AGN by analyzing the XMM- (Iwasawa et al. 2011a), whereas NuSTAR does Newton and Swift/BAT spectra. The NuS- not. The Chandra spectrum is reproduced by TAR study by Oda et al.(2017) finds the ab- the starburst-dominant model with a photon in- sorption column density to be NH ∼ 1.3 × dex fixed at 1.8. 1024 cm−2. By utilizing all the available data of NuSTAR, Chandra, XMM-Newton, Suzaku, 23. IRAS F10257–4339 (NGC 3256): and Swift/BAT, we obtain almost the same re- NGC 3256 is an LIRG in merger stage-D, show- sults as Oda et al.(2017) but newly find that ing two nuclei with a separation of 500. 1 (1.0 kpc; the column density is variable from NH = Ricci et al. 2017a). Lehmer et al.(2015) per- +0.3 24 −2 (1.5−0.2) × 10 cm (Chandra, XMM-Newton, form an X-ray spectral analysis using the NuS- +0.4 23 −2 and Suzaku) to (9.6−0.2) × 10 cm (NuSTAR TAR and Chandra data, and conclude that the and Swift/BAT). The absorption-corrected X-ray flux at >3 keV is dominated by those from ∼5– +0.25 luminosity we estimate is logL2−10 = 43.15−0.15. 10 ultraluminous X-ray sources (ULXs). We find that the broadband spectra of NuSTAR, Chandra, 20. IRAS F09333+4841 W/E (MCG+08-18-012 and and XMM-Newton can be reproduced with the MCG+08-18-013): starburst-dominant model. However, the best-fit +11.1 The two galaxies are in a stage-A merger with a values of Γ = 2.06 ± 0.12 and Ecut = 16.1−4.9 keV separation of 6500. 3 (33.6 kpc). MCG+08-18-013 are not typical of ULXs, which exhibit spectral 61

turnovers between 6 and 8 keV (e.g., Bachetti et al. one (MCG–05-29-017) has a lower IR luminosity of 2013; Walton et al. 2013, 2014b; Delvecchio et al. logLIR/L = 10.54 (see Ricci et al. 2017a). NuS- 2014; Rana et al. 2015). Thus, we suggest that TAR detects no X-ray emission from either nucleus the hard X-ray flux is not dominated by ULXs, in the soft or hard bands (Ricci et al. 2017a). We although their contribution may not be negligible. analyze the Chandra spectra with the starburst- dominant model, where we obtain Γ ∼ 1.7 for 24. IRAS F10565+2448: ESO 440-58 (without an apec component) but fix This ULIRG is a stage-D merger composed of Γ = 1.8 for MCG–05-29-017. two nuclei separated by 700. 4 (6.7 kpc; Ricci et al. 2017a). The western galaxy should be the coun- 27. IRAS F12112+0305: terpart of the IRAS source as it is the only source This ULIRG is a stage-D merger with two nuclei detected in the Spitzer/IRAC images. Soft X- separated by 300. 0 (4.1 kpc; Imanishi et al. 2020). ray emission also comes only from the western The Chandra (Teng et al. 2005; Iwasawa et al. galaxy, which is detected with Chandra and XMM- 2011a) and XMM-Newton studies (Franceschini Newton (Teng & Veilleux 2010; Iwasawa et al. et al. 2003) suggest that the object is starburst- 2011a). Neither of them is detected with NuS- dominated. No X-ray emission is detected with TAR (Teng & Veilleux 2010; Ricci et al. 2017a). NuSTAR in either the soft or hard X-ray band. Analyzing the spectra of the system observed with The 3σ upper limit of the X-ray AGN luminosity Chandra, XMM-Newton, and Suzaku with the (lim) is logL < 43.47 assuming logN ≤ 24.5, and starburst-dominant model, we obtain a photon in- 2−10 H hence the possible presence of a CT AGN cannot dex of Γ ≤ 1.55. be excluded. By adopting the starburst-dominant 25. IRAS F11257+5850 W/E (NGC 3690 West and model, the Chandra and XMM-Newton data con- NGC 3690 East): strain the photon index to be Γ = 1.75 ± 0.22. IRAS F11257+5850 (= Arp 299) is a LIRG in 28. IRAS F12243–0036 NW/SE (NGC 4418 and merger stage-C with two galaxies NGC 3690 West MCG+00-32-013): (= Arp 299B) and NGC 3690 East (= Arp 299A) separated by 2200. 0 (4.6 kpc). Both galaxies are The system is a stage-A merger including a LIRG strong IR sources, and the IRAS HIRES flux in the north-western galaxy NGC 4418 (= NGC ratio between the west and east galaxies is 1:3 4355). The south-eastern source MCG+00-32- (Surace et al. 2004). We identify NGC 3690 013 (= VV 655) is a dwarf galaxy separated West as the hard X-ray detected AGN. The de- by 17900. 9 (29.4 kpc), which would enhance the tailed Chandra studies (e.g., Iwasawa et al. 2011a; starburst activity in NGC 4418 (Varenius et al. Anastasopoulou et al. 2016) verify the presence of 2017; Boettcher et al. 2020). NGC 4418 hosts a an AGN in the western galaxy by detecting its compact obscured nucleus (CON) (e.g., Costagli- prominent neutral Fe Kα line, whereas the east- ola et al. 2013; Sakamoto et al. 2013; Ohyama ern galaxy only shows ionized Fe Kα lines, which et al. 2019). Chandra detects weak X-ray emis- could arise from hot gas in the star-forming re- sion from NGC 4418 but the presence of an AGN gion. Combining the Chandra data with NuSTAR has been a matter of controversy due to the low observation, Ptak et al.(2015) confirm the pres- statistics (Maiolino et al. 2003; Lehmer et al. ence of the CT AGN in NGC 3690 West (NH ∼ 2010; Torres-Alb`aet al. 2018). Hard X-rays are 4×1024 cm−2) while detecting no hard X-ray emis- not detected with NuSTAR and the 3σ upper sion from NGC 3690 East. With XCLUMPY, we limit of the absorption-corrected AGN luminos- +0.6 ity is logL(lim) < 41.82 assuming logN ≤ 24.5. also confirm the CT obscuration (NH = 3.0−0.5 × 2−10 H 1024 cm−2) with an estimate absorption-corrected Thus, if NGC 4418 has an AGN, it should be +0.34 a low-luminosity and/or heavily obscured one luminosity of logL2−10 = 42.66−0.32 for NGC 3690 West. (logNH & 25.0). Analyzing the Chandra and Suzaku spectra with the starburst-dominant 26. IRAS F12043–3140 N/S (ESO 440-58 and MCG– model, we obtain a photon index of Γ ≤ 1.65. 05-29-017): X-ray emission is not detected from MCG+00-32- This is a stage-B merger showing two nuclei with a 013 with either NuSTAR or Chandra. separation of 1100. 8 (5.5 kpc). The northern galaxy (ESO 440-58) is a LIRG, whereas the southern 62 Yamada et al.

29. IRAS F12540+5708 (Mrk 231): 31. IRAS F13126+2453 (IC 860): Mrk 231 (= UGC 8058) is the most luminous The source is a stage-N LIRG. No significant X-ray ULIRG (logLIR/L = 12.57) in our sample, classi- emission is detected with Chandra (see also e.g., fied as a stage-D merger with a single nucleus. Pre- Lehmer et al. 2010) or NuSTAR. Despite the low vious multiwavelength studies reveal the presence count rates, this galaxy is classified as an AGN of multiphase outflows, that is, UFO (e.g., Mizu- in view of its Chandra X-ray color (Torres-Alb`a moto et al. 2019), ionized outflow (e.g., Fluetsch et al. 2018). Using the NuSTAR count rates, we et al. 2019, 2021), and strong molecular outflow constrain the 3σ upper limit of the absorption- −1 (lim) with >500 km s (Sturm et al. 2011; Cicone et al. corrected AGN luminosity as logL2−10 < 41.94 as- 2014). Mrk 231 also shows spatially unresolved suming logNH ≤ 24.5. Since IC 860 hosts a CON BAL systems in the optical and near-UV spectra (e.g., Costagliola et al. 2011), heavily CT obscura- (Boksenberg et al. 1977; Smith et al. 1995; Gal- tion is possible and thus the classification remains lagher et al. 2002, 2005; Rupke et al. 2002). We ambiguous. identify Mrk 231 as the hard X-ray detected AGN. 32. IRAS 13120–5453: The source has been detected with Chandra (e.g., Ptak et al. 2003; Grimes et al. 2004; Gallagher This ULIRG is a stage-D merger with a single et al. 2002, 2005; Iwasawa et al. 2011a), XMM- nucleus. We identify the galaxy as the hard X- Newton (e.g., Franceschini et al. 2003; Turner & ray detected AGN. The NuSTAR and Chandra Kraemer 2003; Braito et al. 2004), and NuSTAR study of Teng et al.(2015) identifies a CT AGN. (e.g., Teng et al. 2014; Feruglio et al. 2015). Teng By adding the XMM-Newton data to them, we et al.(2014) suggest the presence of an obscured also confirm the CT obscuration of NH = (1.6 24 −2 AGN and variability in the absorption column ± 0.2) ×10 cm , and estimate the absorption- 23 −2 +0.59 density from NH ∼ 2 × 10 cm in 2003 (Chan- corrected luminosity to be logL2−10 = 42.17−0.11. dra) to N ∼ 1×1023 cm−2 in 2012 (Chandra and H 33. IRAS F13188+0036 (NGC 5104): NuSTAR). Using the NuSTAR, Chandra, XMM- Newton, and Suzaku observations, we estimate the This is a LIRG classified as a stage-N source. time-averaged column density of NH = (8.5 ± 0.2) Privon et al.(2020) report that NuSTAR does not 22 −2 ×10 cm and the X-ray luminosity of logL2−10 detect the source, while the soft X-ray emission is = 42.65 ± 0.02. detected with Swift/XRT. They find an observed 2–10 keV luminosity of ∼1.5 ×1040 erg s−1, which 30. IRAS F12590+2934 S/N (NGC 4922S and NGC is smaller than a predicted value from the SFR 4922N): with the Lehmer et al.(2016) relation. Thus, no The system is a stage-C merger with the two evidence for an AGN is provided. Analyzing the galaxies separated by 2200. 1 (10.6 kpc). The north- spectrum with the starburst-dominant model, we +0.17 ern source (NGC 4922N) is a LIRG, whereas obtain a photon index of Γ = 2.67−0.52. the southern (NGC 4922S) is less luminous 34. IRAS F13197–1627 (MCG–03-34-064): (logLIR/L = 8.87; Ricci et al. 2017a). We iden- tify NGC 4922N as the hard X-ray detected AGN. This LIRG is a stage-N object. We identify MCG– The X-ray study with NuSTAR and Chandra 03-34-064 as the hard X-ray detected AGN. Ricci by Ricci et al.(2017a) suggests a CT AGN in et al.(2017a) carry out a broadband spectral anal- 24 −2 NGC 4922N (NH ≥ 4.27 × 10 cm ). Our anal- ysis using the XMM-Newton and Swift/BAT spec- ysis with XCLUMPY supports the presence of tra, and reveal the presence of an obscured AGN in 23 −2 the obscured AGN, with an absorption-corrected this object (NH ∼ 5 × 10 cm ). By combining +0.20 X-ray luminosity of logL2−10 = 42.00−0.18, al- these data with the NuSTAR and Chandra data, though the absorption is somewhat smaller we obtain similar results and find that the hydro- +28.5 23 −2 (NH = 7.6−2.2 × 10 cm ) than that in Ricci gen column density varies from NH = (5.6 ± 0.2) et al.(2017a). X-ray emission from NGC 4922S ×1023 cm−2 (Chandra and XMM-Newton) to +0.3 23 −2 is detected only with Chandra, whose spectrum is (9.8−0.2) ×10 cm (NuSTAR and Swift/BAT). reproduced by the starburst-dominant model with The absorption-corrected X-ray luminosity we es- +0.06 Γ=1.8 (fixed). timate is logL2−10 = 43.27−0.07. 63

35. IRAS F13229–2934 (NGC 5135): 2011b). The NuSTAR and XMM-Newton spec- This LIRG is a stage-N source, with no signs of tral analysis performed by Teng et al.(2015) re- a merger even in the nuclear region (e.g., Saba- port that the AGN shows Compton-thin obscura- 23 −2 tini et al. 2018). The Suzaku 0.5–50 keV spec- tion (∼4×10 cm ). Combining these data with trum indicates the presence of a CT AGN (Singh the Suzaku and Swift/BAT data, we find variabil- +0.5 24 −2 et al. 2012). Using NuSTAR, Chandra, and ity in absorption, NH = (1.7−0.3) × 10 cm +0.6 23 −2 Suzaku, Yamada et al.(2020) perform a broad- (Suzaku in 2006), (5.0−0.3)×10 cm (NuSTAR band X-ray spectral analysis with the XCLUMPY and XMM-Newton in 2013, and Swift/BAT), and +1.1 23 −2 model and identify the galaxy as the hard X- (9.3−1.0)×10 cm (Chandra in 2016 and 2017). ray detected AGN. The estimated column den- The absorption-corrected X-ray luminosity is esti- mated to be logL2−10 = 43.07 ± 0.21. sity and absorption-corrected luminosity are NH = +16.6 24 −2 +0.42 6.7−2.8 × 10 cm and logL2−10 = 43.30−0.26, Iwasawa et al.(2018) discuss a possibility that Mrk 23 −2 respectively. 273 has two AGNs (NH ∼ 3 × 10 cm for the south-western nucleus and N ∼ 1.4 × 1024 cm−2 36. IRAS F13362+4831 S/N (Mrk 266B and Mrk H for the northern nucleus, both of which have 266A): 43 −1 L2−10 ∼ 1 × 10 erg s ). If this scenario is the Mrk 266 (= NGC 5256) is a system composed of case, our results of the column density and lumi- two galaxies in a stage-B merger with a separa- nosity should be regarded as the average and sum 00 tion of 10. 1 (5.6 kpc). The southern source (Mrk of the dual AGNs, respectively. 266B) is a LIRG (logLIR/L = 11.36), whereas the northern source (Mrk 266A) is less luminous 38. IRAS F14348–1447: (logLIR/L = 10.82; Mazzarella et al. 2012). Us- ing the Chandra data, Torres-Alb`aet al.(2018) This ULIRG in merger stage-D is composed of two 00 find that Mrk 266B can be reproduced with an nuclei with a separation of 3. 4 (5.2 kpc; Imanishi obscured AGN model and that Mrk 266A shows & Saito 2014). The southern object is brighter a 6.4 keV Fe Kα line at ∼2.1σ level (Torres- in the IRAC images. We identify IRAS F14348– Alb`aet al. 2018). The XMM-Newton observa- 1447 as the hard X-ray detected AGN. Teng & tion also suggests the presence of CT AGN(s) with Veilleux(2010) report the results of the Chandra bright Fe Kα line(s) (Mazzarella et al. 2012) in and XMM-Newton observations. Chandra detects the Mrk 266 system. Using the NuSTAR, Chan- a higher X-ray flux from the southern nucleus, dra, and XMM-Newton data, Iwasawa et al.(2020) whose X-ray color indicates the existence of an confirm the presence of dual AGNs in the sys- obscured AGN (Iwasawa et al. 2011a). We find tem. They estimate the column densities to be that the detection significance with NuSTAR is 24 −2 22 −2 <3σ in the 8–24 keV band but 3.1σ in the 10– NH ∼ 7×10 cm and NH ∼ 6.8×10 cm and the absorption-corrected X-ray luminosities to be 40 keV band. Combining the NuSTAR, Chan- +0.39 +0.04 dra, and XMM-Newton spectra (∼0.1–30 keV), we logL2−10 = 43.13 and logL2−10 = 41.60 −0.36 −0.02 +1.0 24 −2 for Mrk 266B and Mrk 266A, respectively. identify the CT AGN (NH = 1.3−0.6 × 10 cm ) and estimate the X-ray luminosity to be logL2−10 +0.93 37. IRAS F13428+5608 (Mrk 273): = 42.70−0.40. Mrk 273 (= UGC 8696) is an ULIRG in a stage- D merger, with two nuclei (northern and south- 39. IRAS F14378–3651: 00 western sources) at a separation of 0. 9 (0.7 kpc; This ULIRG is a stage-D merger with a single Ricci et al. 2017a). This shows multiphase out- nucleus. The Chandra X-ray color classifies the flows such as UFO (e.g., Mizumoto et al. 2019), object as an AGN with an observed 2–10 keV ionized outflow (e.g., Fluetsch et al. 2019, 2021), luminosity of ∼3 ×1041 erg s−1. The small X- −1 and molecular outflow with >500 km s (Cicone ray to IR luminosity ratio implies that it is a CT et al. 2014). We identify Mrk 273 as the hard X- AGN candidate (Iwasawa et al. 2011a). NuSTAR ray detected AGN. does not detect any hard X-ray emission (see also The system is well studied with Chandra (e.g., Teng et al. 2015), although the 3σ upper limit of Xia et al. 2002; Ptak et al. 2003; Grimes et al. the absorption-corrected AGN luminosity is large (lim) 2005) and is considered to host an obscured (logL2−10 < 43.65 assuming logNH ≤ 24.5). Ana- AGN in the south-western nucleus (Iwasawa et al. lyzing the Chandra spectrum with the starburst- 64 Yamada et al.

dominant model (without an apec component), we Arp 220W contains a heavily CT AGN (NH & obtain the best-fit photon index of Γ ≤ 1.83. 5×1024 cm−2), whereas no clear hints for an AGN in Arp 220E have been obtained in previous multi- 40. IRAS F14544–4255 W/E (IC 4518A and IC wavelength studies. We identify Arp 220W as the 4518B): hard X-ray detected AGN. The system is a stage-B merger showing two nuclei The Chandra image finds that the >2 keV emis- with a separation of 3500. 5 (11.5 kpc). IC 4518A sion is peaked at the western nucleus (Clements (west) is a LIRG, whereas IC 4518B (east) is et al. 2002; Iwasawa et al. 2005), which shows less luminous in the IR band (logL /L = 11.15 IR an X-ray color consistent with those of obscured and 10.28, respectively, derived from MIPS 24 µm AGNs (Iwasawa et al. 2011a). Paggi et al.(2017) data; Alonso-Herrero et al. 2012). We identify IC constrain the absorption-corrected AGN 2–10 keV 4518A as the hard X-ray detected AGN. luminosities to be <1 ×1042 erg s−1 (west) and Ricci et al.(2017a) report that both nuclei are <0.4 ×1042 erg s−1 (east), which are derived from detected with XMM-Newton and that the hard the 3σ upper limits of the neutral Fe Kα flux of X-ray emission from IC 4518A is also detected the nuclear regions. The spectral study using the by NuSTAR. Their spectral analysis implies that NuSTAR and Chandra data by Teng et al.(2015) each nucleus harbors an obscured AGN. Using the cannot unveil the presence of the CT AGN due to XCLUMPY model, we find the hydrogen column the weak detection in the NuSTAR >10 keV band. 23 −2 density varies from NH = (1.7 ± 0.1) ×10 cm Whereas, they estimate the hydrogen column den- (NuSTAR, Suzaku, and Swift/BAT) to (2.2 ± 0.2) sity of the possible AGN in Arp 220 to be >5.3 23 −2 ×10 cm (XMM-Newton). We estimate the ×1024 cm−2 with the BNTorus model (Brightman absorption-corrected luminosity of the AGN in IC & Nandra 2011a) and >1.2 ×1024 cm−2 with the +0.06 4518A to be logL2−10 = 42.83−0.08. We cannot MYTorus model (Murphy & Yaqoob 2009). confirm the presence of an AGN in IC 4518B, how- ever, whose spectrum is subject to large uncertain- We also confirm the NuSTAR detection of Arp 220 ties due to the contamination from IC 4518A. Ap- in the 8–24 keV band (4.0σ). When the starburst- dominant model is applied to the 0.2–20 keV plying the starburst-dominant model to the XMM- spectra (NuSTAR, Chandra, XMM-Newton and Newton spectrum of IC 4518B, we constrain the photon index to be Γ ≤ 2.25. Suzaku), we constrain the cutoff energy to be >92 keV. Since this value is too high to be ex- 41. IRAS F15250+3608: plained by emission from starburst or ULXs, we This is an ULIRG in merger stage-D showing two suggest that Arp 220W actually hosts a heav- nuclei separated by 000. 7 (0.8 kpc; Scoville et al. ily obscured AGN. We note that intense star- 2000). The Chandra (Teng et al. 2005; Iwa- burst coexists with the AGN, considering the de- sawa et al. 2011a) and XMM-Newton (Frances- tection of a strong highly-ionized Fe Kα line at chini et al. 2003) detect weak soft X-ray emission EFe = 6.67 ± 0.02 keV. Assuming fbin = 10% from the system. No hard X-ray emission is de- as a typical value among the hard X-ray detected tected with NuSTAR with the 3σ upper limit of AGNs in stage-D mergers, our XCLUMPY model (lim) yields a column density of N 9.8 × 1024 cm−2, the absorption-corrected luminosity of logL2−10 < H & 43.41 assuming logNH ≤ 24.5. The photon in- supporting the extreme obscuration. The obtained dex derived from the Chandra and XMM-Newton absorption-corrected X-ray luminosity (logL2−10 spectra with the starburst-dominant model is Γ = = 41.59 ± 0.02) is consistent with the upper limit +0.23 reported by Paggi et al.(2017). 2.07−0.25. 42. IRAS F15327+2340 W/E (Arp 220W and Arp 43. IRAS F16504+0228 S/N (NGC 6240S and NGC 220E): 6240N): Arp 220 (= UGC 9913) is the nearest ULIRG This LIRG is a stage-D merger composed of among the stage-D mergers, containing two nu- two nuclei, NGC 6240S (south) and NGC 6240N clei (west and east components) with a separa- (north), with a separation of 100. 7 (0.8 kpc). This tion of 100. 0 (0.4 kpc). The far-IR and millime- target has been well studied with Chandra (Ptak ter/submillimeter observations (e.g., Downes & et al. 2003; Grimes et al. 2005; Iwasawa et al. Eckart 2007; Gonz´alez-Alfonsoet al. 2012; Scov- 2011a), and it is revealed that both nuclei con- ille et al. 2015; Falstad et al. 2021) suggest that tain CT AGNs showing reflected-dominated spec- 65

tra(Komossa et al. 2003). Puccetti et al.(2016) 46. IRAS F18293–3413: carry out a detailed spectral analysis of the NuS- This LIRG is a stage-N source. The earlier Chan- TAR, Chandra, XMM-Newton, and BeppoSAX dra data are studied by Iwasawa et al.(2011a), data, and confirm the presence of the dual CT whereas a much longer Chandra observation has AGNs (see also Nardini 2017). They estimate the been performed in 2019. NuSTAR detects the +0.21 24 −2 column densities (NH = 1.47−0.17 × 10 cm source only at 20 keV. Analyzing the NuS- +0.72 24 −2 . and NH = 1.55−0.23 × 10 cm ) and the TAR, Chandra, and XMM-Newton data with the absorption-corrected X-ray luminosities (logL2−10 +0.20 +0.24 starburst-dominant model, we obtain a photon in- = 43.72 and logL2−10 = 43.30 ) for NGC −0.19 −0.20 dex of Γ ≤ 1.56 and a cutoff energy of Ecut = 6240S and NGC 6240N, respectively. +2.4 7.6−1.4 keV, consistent with no contribution from an AGN. 44. IRAS F16577+5900 N/S (NGC 6285 and NGC 6286): 47. IRAS F19297–0406: The system is a stage-B merger with the two galax- This source is an ULIRG in merger stage-D show- ies separated by 9100. 0 (34.5 kpc). NGC 6286 is ing a single nucleus. Chandra detects the faint categorized as a LIRG, whereas NGC 6285 is not X-ray emission (Iwasawa et al. 2011a). No emis- a luminous IR source (logLIR/L = 10.72; Ricci sion is detected with NuSTAR, and the 3σ upper et al. 2017a). We identify NGC 6286 as the hard limit of the absorption-corrected AGN luminosity X-ray detected AGN. The Chandra spectrum of (lim) is logL2−10 < 44.08 assuming logNH ≤ 24.5. Al- NGC 6286 shows excess emission above 5 keV though the origin of the emission is ambiguous, (Torres-Alb`aet al. 2018), implying an obscured the Chandra spectrum can be reproduced with AGN. Ricci et al.(2016) find evidence for a CT, the starburst-dominant model with a photon in- 24 −2 low-luminosity AGN (NH ∼ 1 × 10 cm ) in dex fixed at 1.8. NGC 6286, using NuSTAR, Chandra and XMM- Newton. This is in good agreement with our mea- 48. IRAS F20221–2458 SW/NE (NGC 6907 and NGC surements with XCLUMPY (NH = 1.4 ± 0.3 × 6908): 24 −2 10 cm ). The absorption-corrected luminos- The LIRG NGC 6907 and the nearby dwarf +1.21 ity we obtain is logL2−10 = 42.01−0.23. From galaxy NGC 6908 are interacting systems clas- NGC 6285, weak soft X-ray emission is detected sified as stage-B with a separation of 4300. 9 with Chandra and XMM-Newton. The starburst- (9.4 kpc). Privon et al.(2020) report that dominant model without an apec component yields NGC 6907 is detected with Swift/XRT but not +0.36 a photon index of Γ = 2.14−0.33. with NuSTAR. The observed 2–10 keV luminosity (∼7 ×1039 erg s−1) is even lower than the expected 45. IRAS F17138–1017: value (∼8 ×1040 erg s−1) from the SFR, suggest- This LIRG is a stage-D merger with a single nu- ing that there is no significant AGN contribution cleus. We identify IRAS F17138–1017 as the hard to the X-ray flux. We find that the combined NuS- X-ray detected AGN. The Chandra X-ray spec- TAR and Swift/XRT spectra below 10 keV can trum indicates its classification as an obscured be well fitted with the starburst-dominant model AGN (Torres-Alb`aet al. 2018). Ricci et al.(2017a) (Γ = 1.8 fixed). No X-ray emission is detected fit the combined NuSTAR and Chandra spectra from NGC 6908 in these observations. with a simple power-law model and obtain a pho- ton index of ∼1.1, which is harder than typical 49. IRAS 20264+2533 W/E (NGC 6921 and spectra of starbursts. We confirm that NuSTAR MCG+04-48-002): detects the 8–24 keV emission at 4.4σ (or 3.9σ) This system is a stage-A merger composed of NGC level using the source counts in a 3000 (or 4500) ra- 6921 and the LIRG MCG+04-48-002 with a sep- 00 dius. Assuming fbin = 10%, our spectral anal- aration of 91. 4 (26.5 kpc). We identify both ysis with XCLUMPY suggests the presence of a NGC 6921 and MCG+04-48-002 as the hard X- CT AGN with a column density of NH > 3.5 ray detected AGNs. The NuSTAR and XMM- ×1024 cm−2 and an absorption-corrected luminos- Newton studies (Koss et al. 2016; Ricci et al. +0.09 ity of logL2−10 = 41.68−0.06. These values should 2017a) suggest that both nuclei have obscured or be referred to with caveats due to the assumption CT AGNs, well consistent with our results. We of fbin. find that NGC 6921 contains a CT AGN with 66 Yamada et al.

24 −2 NH = (1.7 ± 0.3) ×10 cm and logL2−10 = XMM-Newton spectra, we obtain a photon index +0.37 +0.11 42.80−0.44. Whereas, MCG+04-48-002 hosts an of Γ = 1.64−0.12. obscured AGN, whose column density varies from 23 −2 52. IRAS F21453–3511 (NGC 7130): NH = (6.0 ± 0.5) ×10 cm (XMM-Newton and +1.5 23 −2 The LIRG NGC 7130 is a possible past merger Swift/BAT) to (7.3−0.8) ×10 cm (NuSTAR). The absorption-corrected luminosity measured by (Davies et al. 2014), classified as a stage-N source NuSTAR is logL2−10 = 42.44 ± 0.15, showing flux in this paper. We identify the galaxy as the Time +0.67 hard X-ray detected AGN. The Chandra spectrum variability (C = 3.55−0.56 for XMM-Newton +0.65 shows a hard excess and a strong Fe Kα line at and 5.46−0.58 for Swift/BAT). 6.4 keV, suggesting an obscured or CT AGN (e.g., 50. IRAS F20550+1655 W/E (II Zw 096 and IRAS Levenson et al. 2005; Torres-Alb`aet al. 2018). F20550+1655 SE): With a combined analysis of the NuSTAR and The LIRG IRAS F20550+1655 (= CGCG 448- Chandra spectra, Ricci et al.(2017a) and Pozzi 020) is a stage-C merger showing two main galax- et al.(2017) confirm the presence of CT obscura- ies with a separation of 1100. 6 (8.1 kpc). Zenner & tion. Adding the Suzaku and Swift/BAT spectra Lenzen(1993) identify four near-IR peaks, desig- to the NuSTAR and Chandra ones, we estimate nated as the galaxy A (= IRAS F20550+1655 SE the column density and absorption-corrected lu- 24 −2 minosity to be NH = (4.1 ± 0.1) ×10 cm and or CGCG 448-020W), the galaxy B (= II Zw 096), +0.31 and the sources C and D (= CGCG 448-020E), logL2−10 = 42.87−0.25, respectively. which are two prominent red knots, as shown by 53. IRAS F23007+0836 S/N (NGC 7469 and IC 5283): Figure 2 in Goldader et al.(1997). Source D ra- The system is a stage-A merger with the two galax- diates >70% of the 24 µm emission in the MIPS ies NGC 7469 and IC 5283 separated by 7900. 7 image (Inami et al. 2010), which is the closest to (26.2 kpc). NGC 7469 is a LIRG, whereas IC 5283 the IRAS peak position. Iwasawa et al.(2011a) has a smaller IR luminosity of logL /L = 10.79 report that Chandra detects two compact X-ray IR (Ricci et al. 2017a). NGC 7469 hosts a bright un- emitters from the galaxy A and the sources C+D. obscured AGN detected by Chandra/High Energy The sources C+D show a hard X-ray color consis- Transmission Grating Spectrometer (Scott et al. tent with an AGN, although this may be due to 2005), XMM-Newton (Blustin et al. 2003), Suzaku absorption within the red knots. No hard X-rays (Walton et al. 2013; Iso et al. 2016), and NuSTAR above 8 keV are detected with NuSTAR. Using (e.g., Ricci et al. 2017a; Middei et al. 2018; Ogawa the soft X-ray spectra of NuSTAR, Chandra, and et al. 2019). Recently, Ogawa et al.(2021) per- XMM-Newton, we obtain Γ ≤ 1.53 and E = cut form an spectral analysis with XCLUMPY, using 12.2+4.5 keV for the galaxy IRAS F20550+1655 −2.7 the NuSTAR and XMM-Newton spectra. Their SE (including sources C+D), indicating that the results are in good agreement with the previous X-ray source is starburst-dominant. The galaxy in works. In this paper, we refer to Ogawa et al. II Zw 096 is detected only with Chandra and its (2021) for the column density (<1.5 ×1019 cm−2) spectrum yields a photon index of Γ ≤ 2.02. and absorption-corrected luminosity (logL2−10 = +0.03 51. IRAS F20551–4250 (ESO 286-19): 43.26−0.02). No significant X-ray emission from IC 5283 is detected with XMM-Newton. This ULIRG is a stage-D merger with a single nu- cleus. Chandra detects an X-ray source (Ptak 54. IRAS F23128–5919 (ESO 148-2): et al. 2003; Grimes et al. 2005; Iwasawa et al. This ULIRG is a stage-C merger with two galax- 2011a), which is classified as an obscured AGN ies separated by 400. 5 (3.9 kpc; Zenner & Lenzen with XMM-Newton (Franceschini et al. 2003). 1993). We identify this pair (ESO 148-2) as the NuSTAR detects the 8–24 keV emission at a low hard X-ray detected AGN. Previous studies us- significance level (2.0σ), and also an ionized or ing Chandra (Ptak et al. 2003; Grimes et al. 2005; +0.12 neutral Fe Kα line (EFe = 6.56−0.32 keV and Iwasawa et al. 2011a) and XMM-Newton (Frances- +0.41 −6 AFe = 0.45−0.31 × 10 ). The 3σ upper limit of chini et al. 2003) demonstrate that the southern int(lim) the AGN luminosity is logL2−10 < 43.38 assum- nucleus hosts an obscured AGN. NuSTAR detects ing logNH ≤ 24.5, and thus the possibility of an the 8–24 keV emission (3.1σ) and variable spec- obscured AGN remains. Applying the starburst- tral features between the NuSTAR and other soft dominant model to the NuSTAR, Chandra, and X-ray observations, indicating the presence of an 67

AGN. Adopting the XCLUMPY model, we find in these observations. that the column density increases dramatically +0.9 from a Compton-thin level with NH = (2.7−0.6) × 57. IRAS 23262+0314 W/E (NGC 7679 and NGC 1022 cm−2 (Chandra and XMM-Newton) to a CT 7682): 24 −2 level with NH = (1.6 ± 0.5) × 10 cm (NuS- The system is a stage-A merger with the two TAR), as reported in Section 6.1.5. The estimated galaxies NGC 7679 and NGC 7682 separated by absorption-corrected AGN luminosity is logL2−10 26900. 8 (93.8 kpc). While NGC 7679 is a LIRG, +0.24 = 42.38−0.28. NGC 7682 is less luminous in the IR band. We identify NGC 7679 and NGC 7682 as the hard 55. IRAS F23157+0618 (NGC 7591): X-ray detected AGNs. The BeppoSAX observa- This LIRG is a stage-N object. The X-ray emis- tion in 1998 (Risaliti 2002; Dadina 2007) suggests sion is not detected with Chandra (Torres-Alb`a that NGC 7679 has an unobscured AGN with a et al. 2018) or NuSTAR (Privon et al. 2020). The 2–10 keV luminosity of 3.4×1042 erg s−1. Analyz- low soft X-ray luminosity indicates that it is a ing the XMM-Newton data taken in 2005, Ricci starburst-dominant source. Even though we can- et al.(2017a) find a flux decline by a factor of not rule out the possibility of a CT AGN, the ∼10 (4 × 1041 erg s−1). Furthermore, using the 3σ upper limit of the absorption-corrected AGN NuSTAR and Swift/XRT data in 2017 and the (lim) luminosity is small (logL2−10 < 42.51 assuming time averaged (2005–2013) Swift/BAT data, we logNH ≤ 24.5). detect a re-brightening of the unobscured AGN 15 −2 (NH < 3 ×10 cm ) with a larger absorption- 56. IRAS F23254+0830 W/E (NGC 7674 and +0.06 corrected luminosity (logL2−10 = 42.34−0.04) com- MCG+01-59-081): pared with that in the XMM-Newton observation IRAS F23254+0830 has two galaxies in a stage- (CTime = 0.16 ± 0.01). Whereas, NGC 7682 hosts A merger, separated by 3300. 3 (19.5 kpc). NGC a CT AGN revealed by XMM-Newton (Singh 7674 is a LIRG, while MCG+01-59-081 (= NGC et al. 2011; Ricci et al. 2017a) and Swift/BAT 7674A) has a lower IR luminosity (logLIR/L (Ricci et al. 2015). Analyzing the NuSTAR and = 10.01; Ricci et al. 2017a). We identify NGC XMM-Newton spectra with XCLUMPY, how- 7674 as the hard X-ray detected AGN. Bianchi ever, we obtain a smaller column density of 23 −2 et al.(2005) report a decline of the 2–10 keV NH = (3.8 ± 0.7) × 10 cm with an X-ray flux between the (in 1989) and BeppoSAX luminosity of logL2−10 = 41.94 ± 0.06. observations (in 1996), which may be the rea- son for the large bolometric-to-X-ray correction factor, as noted in Section 6.1.1. Gandhi et al. C. X-RAY SPECTRA AND BEST-FIT MODELS (2017) analyze the broadband X-ray spectra of In this section, we display the X-ray spectra with the NuSTAR, Suzaku/XIS, and Swift/XRT, and in- best-fit models and ratios between the data and the dicate the presence of a reflection-dominated CT models of all the sources in our sample (Figures C1– 24 −2 AGN (NH & 3 × 10 cm ) assuming three C5: AGN model, Figures C6–C10: starburst-dominant geometries of the nuclear obscurer and reflec- model). The spectra are unfolded with the energy re- tor. By contrast, Tanimoto et al.(2020) report sponses and are presented in units of EF (E), where that the XCLUMPY model can also reproduce F (E) is the energy flux at the energy E. When the the spectra with a smaller column density of Cash statistics are adopted in the spectral fit, we merge 23 −2 NH ∼ 2 × 10 cm . Using the NuSTAR, XMM- the spectral bins to ensure a significance of >3σ per bin Newton, Suzaku/XIS and HXD, and Swift/BAT for viewing purposes. The colors of the spectra clas- spectra, we find that the column density is vari- sify the data of NuSTAR/FPM (black), Chandra/ACIS +0.5 23 −2 able, NH = (1.4−0.4) ×10 cm (XMM-Newton (red), XMM-Newton/MOS (green), XMM-Newton/pn +0.3 23 −2 in 2004), (1.0−0.2) ×10 cm (Suzaku in 2013), (blue), Suzaku/XIS-FI (cyan), Suzaku/XIS-BI (ma- +0.3 23 −2 and (3.0−0.2) ×10 cm (NuSTAR in 2014 and genta), Suzaku/HXD (orange), Swift/XRT (purple), Swift/BAT). The estimated absorption-corrected and Swift/BAT (sky blue). +0.33 X-ray luminosity is logL2−10 = 42.59−0.23. No X-ray emission is detected from MCG+01-59-081 68 Yamada et al.

Figure C1. X-ray spectra, best-fit models, and ratios between the data and models of the AGNs in NGC 34 [NH = (5.0 ± 1.0) 23 −2 +0.8 23 −2 23 −2 ×10 cm ], NGC 235 [NH = (5.1−0.6) ×10 cm ; and (2.9 ± 0.2) ×10 cm for Chandra], MCG+12-02-001 [NH = (>4.3 24 −2 23 −2 +0.1 23 −2 ×10 cm ], NGC 833 [NH = (2.6 ± 0.1) ×10 cm ], NGC 835 [NH = (3.0−0.2) ×10 cm ], and CGCG 468-002W [NH = (1.5 ± 0.1) ×1022 cm−2]. 69

Figure C2. X-ray spectra, best-fit models, and ratios between the data and models of the AGNs in IRAS F05189–2524 [NH = 22 −2 24 −2 +2.4 23 −2 (7.5 ± 0.1) ×10 cm ; and >2.3 ×10 cm for Suzaku], IRAS F06076–2139 [NH = (4.2−1.2) ×10 cm ], NGC 2623 [NH = +4.5 22 −2 +4.0 22 −2 +12.9 23 −2 (6.0−2.1) ×10 cm ], ESO 060-IG016 East [NH = (8.4−2.9) ×10 cm ], IRAS F08572+3915 [NH = (8.5−2.8 ) ×10 cm ], +0.4 23 −2 +0.3 24 −2 and UGC 5101 [NH = (9.6−0.2) ×10 cm ; and (1.5−0.2) ×10 cm for Chandra/XMM-Newton/Suzaku]. 70 Yamada et al.

Figure C3. X-ray spectra, best-fit models, and ratios between the data and models of the AGNs in NGC 3690 West [NH = +0.6 24 −2 22 −2 +28.5 23 −2 (3.0−0.5) ×10 cm ], Mrk 231 [NH = (8.5 ± 0.2) ×10 cm ], NGC 4922N [NH = (7.6−2.2 ) ×10 cm ], IRAS 13120–5453 24 −2 +0.3 23 −2 23 −2 [NH = (1.6 ± 0.2) ×10 cm ], MCG–03-34-064 [NH = (9.8−0.2) ×10 cm ; and (5.6 ± 0.2) ×10 cm for Chandra/XMM- +0.6 23 −2 +1.1 23 −2 +0.5 24 −2 Newton], and Mrk 273 [NH = (5.0−0.3) ×10 cm ; (9.3−1.0) ×10 cm for Chandra; and (1.7−0.3) ×10 cm for Suzaku]. 71

Figure C4. X-ray spectra, best-fit models, and ratios between the data and models of the AGNs in IRAS F14348–1447 [NH = +1.0 24 −2 23 −2 23 −2 (1.3−0.6) ×10 cm ], IC 4518A [NH = (1.7 ± 0.1) ×10 cm ; and (2.2 ± 0.2) ×10 cm for XMM-Newton], Arp 220W 24 −2 24 −2 24 −2 [NH & 9.8 ×10 cm ], NGC 6286 [NH = (1.4 ± 0.3) ×10 cm ], IRAS F17138–1017 [NH > 3.5 ×10 cm ], and NGC 6921 24 −2 [NH = (1.7 ± 0.3) ×10 cm ]. 72 Yamada et al.

Figure C5. X-ray spectra, best-fit models, and ratios between the data and models of the AGNs in MCG+04-48-002 [NH +1.5 23 −2 23 −2 24 −2 = (7.3−0.8) ×10 cm ; and (6.0 ± 0.5) ×10 cm for XMM-Newton/Swift], NGC 7130 [NH = (4.1 ± 0.1) ×10 cm ], 24 −2 +0.9 22 −2 +97.5 23 −2 ESO 148-2 [NH = (1.6 ± 0.5) ×10 cm ; (2.7−0.6) ×10 cm for Chandra/XMM-Newton; and (2.5−1.8 ) ×10 cm for +0.3 23 −2 +0.5 23 −2 +0.3 23 −2 Swift], NGC 7674 [NH = (3.0−0.2) ×10 cm ; (1.4−0.4) ×10 cm for XMM-Newton; and (1.0−0.2) ×10 cm for Suzaku], 15 −2 23 −2 NGC 7679 [NH < 3 ×10 cm ], and NGC 7682 [NH = (3.8 ± 0.7) ×10 cm ]. 73

Figure C6. X-ray spectra, best-fit models, and ratios between the data and models of the starburst-dominant or hard X-ray undetected sources in MCG–02-01-052, MCG–02-01-051, ESO 350-38, NGC 232, IC 1623B, and NGC 838. 74 Yamada et al.

Figure C7. X-ray spectra, best-fit models, and ratios between the data and models of the starburst-dominant or hard X-ray undetected sources in NGC 839, MCG+08-18-013, MCG–01-26-013, NGC 3110, ESO 374-IG032, and NGC 3256. 75

Figure C8. X-ray spectra, best-fit models, and ratios between the data and models of the starburst-dominant or hard X-ray undetected sources in IRAS F10565+2448, ESO 440-58, MCG–05-29-017, IRAS F12112+0305, NGC 4418, and NGC 4922S. 76 Yamada et al.

Figure C9. X-ray spectra, best-fit models, and ratios between the data and models of the starburst-dominant or hard X-ray undetected sources in NGC 5104, IRAS F14378–3651, IC 4518B, IRAS F15250+3608, NGC 6285, and IRAS F18293–3413. 77

Figure C10. X-ray spectra, best-fit models, and ratios between the data and models of the starburst-dominant or hard X-ray undetected sources in IRAS F19297–0406, NGC 6907, II Zw 096, IRAS F20550+1655 SE, and ESO 286-19. 78 Yamada et al.

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