Draft version July 27, 2019 Typeset using LATEX default style in AASTeX62 Spatially Resolved Kinematics of Ionized Gas with CFHT's SITELLE in the Merging Luminous Infrared Galaxy: Mrk 266 - Host of Dual-AGN Maya Merhi,1 Andreea Petric,2, 3 Laurie Rousseau-Nepton, Simon Prunet, Nicolas Flagey,4 and Laurent Drissen, Carmelle Robert5 1Lycoming College, 700 College Pl. Williamsport, PA 17701, USA 2Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822, USA 3CanadaFranceHawaii Telescope, 65-1238 Mamalahoa Highway, Kamuela, HI 96743, USA 4CanadaFranceHawaii Telescope, 65-1238 Mamalahoa Hi, Kamuela, HI 96743, USA 5Universite Laval,Quebec, QC, Canada, G1V0A6A Abstract We present the first wide-field study of the spatially resolved ionized gas kinematics in the well studied, nearby dual-AGN host Markarian 266 (Mrk 266, NGC 5256). Mrk 266 is a gas-rich luminous 11 infrared galaxy (LIRG: galaxy with LIR > 10 L ) merger at z ∼ 0:0278 that hosts Mrk 266 SW - a Seyfert, and Mrk 266 NE - a LINER. Using the Canada France Hawaii Telescope's (CFHT's) SITELLE instrument we study the effect of dual-AGN on Mrk 266's ISM and the surrounding medium. We present the morphologies and kinematics of the Hα, [NII], Hβ, and [OIII] emissions. Using emission line diagnostics, we find that 5% of the Hα gas comes from new stars in HII regions, while 35% is composite (LINER + HII) emission, and 50% is from shocked gas, either associated with the AGN, or with the tidal disruption. Mrk 266's complex [OIII] dynamics allow us to speculate that Mrk 266 is analogous to some of the high redshift, dusty systems observed to have high velocity [OIII] outflows. We also suggest that galaxies like Mrk 266 enrich the circumgalactic medium (CGM) in agreement with theoretical work on the role of mergers in transporting metals to the CGM. 1. INTRODUCTION 11 Luminous Infrared Galaxies (LIRGs: galaxies with LIR > 10 L ) are fundamental to the study of galaxy evolution. LIRGs form stars faster than nearby normal galaxies, and in the local universe (z < 0:088 ) 20% of LIRGs contain growing super massive black holes known as active galactic nuclei (AGN) that emit more energy in the infrared than the rest of the emission in the galaxy combined (e.g, Sanders et al. 1988; Armus et al. 2009; Petric et al. 2011; Petric et al. 2018). Half of nearby LIRGs are gravitationally interacting systems, and ∼ 10% exhibit large-scale outflows known as superwinds (Mazzarella et al. 2012; Petric et al. 2011; Rich et al. 2014). Thus, LIRGs exhibit interesting physical processes known to shape galaxies, dominate the total star formation density at z ∼ 1 , and are an important population at higher redshift (Le Floc'h et al. 2005; Magnelli et al. 2009). Nearby merging LIRG systems are ideal targets in which to study the connections between gravitational galactic interactions and black hole growth. Merging gas-rich galaxies trigger AGN, as galaxy-wide shocks decrease the gas' angular momentum and kinetic energy. In a system with two AGN, gas is funneled toward the center of the systems, feeding the central supermassive black holes (SMBHs) and powering AGN activity, while the nuclei are still apart (Colpi et al. 2009). The study of gas-rich merging systems with two AGN is integral to the understanding of galaxy merger evolution, because dual-AGN systems represent a short-lived, but rich dynamical phase of the galaxy merger evolutionary path. However, observations of dual-AGN are rare because most of their activity occurs in small and often obscured regions, and because the duration of the AGN duty-cycle and gas motions associated with the mergers appear to conspire. 2 Merhi et al. One of the most intriguing LIRGs found in the local universe is Mrk 266 (Figure1). Mrk 266 is a gas-rich merger that harbors dual-AGN: Mrk 266 SW - a Seyfert, and Mrk 266 NE - a low-ionization nuclear emission-line region (LINER). While the true nature of LINERs has been vigorously debated in the literature, Kewley et al.(2006) show that LINERs are AGN, and that the Seyfert/LINER dichotomy is analogous to the high-low state modes in X-ray binary states. Mazzarella et al.(2012) used multi-wavelength photometric data together with several MIR low- resolution spectra to study Mrk 266. These authors proposed that Mrk 266 belongs to an evolutionary path in which dual-AGN with kiloparsec separations are predecessors to binary AGN with parsec-scale orbital radii. Mazzarella et al. (2012), however, lacked kinematic information throughout entire system. As such, both the gas depletion rates and merger time-scales are uncertain in their investigation. We observed Mrk 266 using SITELLE (Spectrom`etreImageur `aTransform´eede Fourier pour l'Etude en Long et en Large de raies d'Emission) at the Canada-France-Hawaii Telescope (CFHT). We used SITELLE's large field of view to probe the large merging systems including tidal tales, kiloparsec winds, and the environment surrounding the dual-AGN. Here, we take advantage of the wide field, spatial, and velocity resolution of the SITELLE instrument at CFHT to measure the amount of Hα and Hβ line emissions, from which we derive extinction corrected star-formation rates. This, together with published maps of cold molecular gas, will give us a better estimate of the depletion time- scales associated with star-formation. We use emission line diagnostics to quantify the amount of shocked gas, and assess the impact of this gas on the star-formation evolution of the systems. We also derive velocity and dispersion maps to investigate how outflowing gas may impact the circumgalactic medium. In this paper, we also briefly explore the possible analogies between Mrk 266 and high redshift dusty quasars with powerful outflows. Figure 1: Combined image of Mrk 266, Hα at 6563A˚ and the [NII] doublet at 6548A˚ and 6583A˚ and continuum emission in SITELLE's SN3 filter. The σ limit of this integrated emission map is 1:340 × 10−18. Mrk 266 is a complex system: two bright nuclei containing more than 13% AGN emission (Mazzarella et al. 2012), a bridge of shocked gas between the two nuclei, and a filamentary nebulae of ionized hydrogen (Armus et al. 1990; Petrosian et al. 1980). We mark those regions in Figure2. Ionized gas Kinematics in dual-AGN host Mrk 266 3 Figure 2: Image of Mrk 266 showing the features of interest. Features of interest identified in red: appearance of superwinds (left arrow), Mrk 266 NE which is classified as a LINER (left circle), Mrk 266 SW which is classified as a Seyfert 2 (right circle), Northern Loop (right arrow). 2. METHODOLOGY Mazzarella et al.(2012) point out several striking features in Mrk 266: (1) the NE nucleus, (2) the SW nucleus, (3) extending ∼ 2500 (15kpc) to the north is a fragmented, filamentary structure known as the Northern Loop, (4) faint emission extending ∼ 6000 (24kpc) to the southeast from the center of the system appears to be tidal debris. The morphology and vast extend of emission are consistent with numerical simulations of tidal debris created during major mergers (e.g Dubinski et al. 1999; Stoehr et al. 2006). Throughout this paper, we will refer to those major structures detailed by the Mazzarella et al.(2012) study as the Northern loop, the NE nucleus, the SW nucleus, the bridge, and the Southern extended emission. Mrk 266 is at a redshift of 0.0278 corresponding to a recession velocity of 8400 km/sec. We adapt the cosmological parameters of: Hubble parameter - h = 0:7, matter denisty - Ωm = 0:3, and dark energy density - ΩΛ = 0:7, which correspond to a luminosity distance of 129 Mpc and a spatial scale of 0.59 kpc arcsec−1. 2.1. Observations On 11 and 12 May 2019, Mrk 266 (RA, Dec [J2000]: 13h 38m 17.5s +48d 16m 37s) was observed with SITELLE on the Canada France Hawaii Telescope. The seeing on both nights varied between 0.7 " to 0.9 ". SITELLE's FOV is 11 by 11 arcmuinutes, allowing us a first look at the 100 kpc extended emission kinematics in a nearby dual- AGN system. We use the SN2 filter (480-520 nm) to map the Hβ at 4861A,˚ and [OIII] at 4959A,˚ and 5007A˚ line emissions and the SN3 filter (651-685 nm) to map the Hα at 6563A˚ and [NII] at 6548A˚ and 6583A.˚ Table1 gives the observing parameters. 4 Merhi et al. Table 1: SITELLE observations of Mrk 266 Lines Filter Res. (λ/∆λ) Steps Exp. time/step Int. time [hr] Seeing Hα, [NII] SN3 (647-685nm) 2000 347 51.0 5.23 0.7" Hβ; [OIII] SN3 (483-513nm) 1000 225 74.0 4.83 0.9" 2.2. Fitting the Spectra Using ORCS, a software designed specially for SITELLE data cubes (Martin et al. 2015), we begin by fitting single pixels in different dynamical regions of the galaxy to estimate input parameters for the fit such as velocity and velocity dispersion (σv). Extracting these parameters determines how the ionized gas is behaving in the galaxy. We use the method fit lines in spectrum() to extract and fit the spectrum of a single pixel. The pixels are input to the method in the format: (X coordinate, Y coordinate, Radius). This method is based on the following parameters: • the name of the line(s) to be fitted, • `f model', which indicates the fitting model to be used (sinc, sincgauss, gaussian) (Figure3), • `pos def', which defines whether emission lines are fit with the same velocity or with their own individual velocities, and `pos cov', which defines the initial guess for the velocity, • `sigma def', which defines whether emission lines are fit with the same velocity dispersion (σv), or with their own individual σv, and `sigma cov', which defines the initial guess for σv of the fitted line(s).