KYDISC: Galaxy Morphology, Quenching, and Mergers in the Cluster Environment

Sree Oh (ANU / ASTRO3D / Yonsei) Keunho Kim, Joon Hyeop Lee, Yun-Kyeong Sheen, Minjin Kim, Chang H. Ree, Luis C. Ho, Jaemann Kyeong, Eon-Chang Sung, Byeong-Gon Park, Sukyoung K. Yi

Australia-ESO Conference 20191 Abell 2218 Andrew Fruchter (STScI) et al., WFPC2, HST, NASA KASI-Yonsei Deep Imaging Survey of Cluster (KYDISC) KYDISC targets 14 Abell clusters at 0.016 < z < 0.146 2 Low surface brightnessTable 1.2. Summary(27 mag/arcsec of observations in 3σ) features

Cluster ID z RA(J2000) Dec(J2000) Instrument Filter texp Spectroscopy hh:mm:ss dd:mm:ss sec Abell 3574 0.016 13:48:54.2 -30:23:01 IMACS Magellan g′, r′ 1250 WFCCD du Pont Abell 1146 0.141 11:01:29.9 -22:46:19 g′, r′ 2500 IMACS Magellan Abell 3659 0.091 20:02:27.4 -30:04:50 g′, r′ 2500 IMACS Magellan Abell 1126 0.084 10:53:49.8 +16:55:18 MegaCam CFHT u′, g′, r′ 2940 Hydra WIYN Abell 2061 0.078 15:21:18.9 +30:36:24 u′, g′, r′ 2940 Hydra WIYN 8 Abell 2249 0.081 17:09:46.7 +34:32:53 u′, g′, r′ 2940 Hydra WIYN Abell 690 0.079 08:39:16.1 +28:55:14 u′, g′, r′ 2940 SDSS Abell 1139 0.040 10:59:56.8 +01:32:51 g′, r′ 2940 SDSS Abell 116 0.067 00:55:48.3 +00:43:15 u′, g′, r′ 2940 SDSS Abell 655 0.126 08:24:50.0 +46:49:52 u′, g′, r′ 2940 HeCS Abell 646 0.126 08:24:50.0 +46:49:52 u′, g′, r′ 2940 HeCS Abell 1278 0.129 11:31:57.2 +20:36:02 u′, g′, r′ 2940 SDSS Abell 667 0.145 08:28:10.3 +44:48:28 u′, g′, r′ 2940 HeCS Abell 2589 0.041 23:25:50.4 +16:54:44 u′, g′, r′ 2940 NED Oh et al. 2018 ApJS 237 14 KYDISC catalogue paper Oh et al. 2018 ApJS 237 14)

Impact of Mergers on the Colour-Magnitude Relation

Phase-Space Analysis and Gravitational Potential Index

Mass-Size Relation of Cluster Galaxies

Mass Segregation in the Cluster Environment

Barred galaxies in clusters KYDISC Catalogue of 1409 cluster galaxies

Redshift

Magnitudes

Structure Parameters

Local density B/T Asymmetry Hubble Type Mergers Oh et al. 2018 ApJS 237 14

Deep Imaging - Magellan/IMACS, CFHT/MegaCam Spectroscopy - Magellan/IMACS, WIYN/Hydra, du Pont/WFCCD Visual Classiﬁcation - Hubble Types Elliptical (E: 35%) Lenticular (S0: 39%)

Early Spiral (SE: 16%) Late Spiral (SL: 10%)

Figure 3.11. Sample images of late spirals.

61 Morphology-Density Relation in the cluster environment

KYDISC - Cluster Dressler (1980) - All Environment E

S S0 S0 E SE

Figure The 3.17. S0 The fraction morphology-density remains relation constant in the cluster environment.regardless The of local density fraction Major of elliptical transformation galaxies increases with from local density; Spirals whereas, theto fractionS0s had happened before their late-typearrival galaxies to decreases clusters comparatively. The fraction of lenticular galaxies does not change signiﬁcantly. Constant S0 fraction: (Spirals ➔ S0s) ≃ (S0s ➔ Ellipticals)

Oh et al. 2018 ApJS 237 14

74 Does fE correlate to cluster velocity dispersion? Virgo Coma poor, irregular cluster virialized rich cluster fE ~ 20% fE ~ 90%

WINGS SDSS

fE fE

Poggianti et al. (2009) Simard et al. (2009)

Previous studies did not detect a correlation between a elliptical fraction and cluster velocity dispersion in the local universe Galaxy Morphology in the Cluster Environment

Morphology B/T E S0 B/T > 0.7 0.4

SE SL 0.2

σcluster σcluster

More massive clusters have more early-type galaxies even in the local Universe

Oh et al. 2018 ApJS 237 14 ➔ Poggianti and Simard samples (R < 0.6R200)

KYDISC covers larger area (2R200) than Simard and Poggianti et al. sample (0.6 R200)

We have better spectroscopic completeness (80%) than previous studies

(35-63%) ➔ KYDISC (R < 2R200) Environmental quenching in a cluster

median Nuv-r colour vs local density NUV blue (recent SF) Fraction

Early Spirals are suffering environmental quenching Gas stripping is almost completed when their ﬁrst passage (Jung et al. 2018) The quenching of S0s might start before they come to clusters (Preprocessing)

Oh et al. 2018 ApJS 237 14 Speculations on Cluster S0s

Preformed S0s Transformed S0s

were spirals when they arrived at had S0 morphology even what cluster outskirts and transformed before they came into clusters into S0s within a cluster environments where anywhere (0< R < 2R200) R < R200

not yet fully quenched when star formation quenched they arrive R200

I don’t know! quenching-driven origin how (merger?) (gas stripping)

S0s at R < R200 = Preformed + Transformed S0s S0s at R > R200 = Preformed S0s Visual Classiﬁcation - Merger related features

Post Merger (20%)

Ongoing Merger (4%)

Figure 3.12. Sample images of galaxies with post-merger features.

Figure 3.13. Sample images of galaxies of ongoing merger.

63 Environmental Dependance of post-merger galaxies

ClusterFigure mass 3.19. Galaxy is not interactions responsible and cluster for velocitythe variation dispersion. of The post-merger cluster fraction velocity dispersion does not show the di↵erence in the fractions of galaxy inter- Post-merger (PM) fraction decreases with local density action. Ongoing merger (OM) fraction remains constant with local density

Oh et al. 2018 ApJS 237 14

78 The origin of post-merger galaxies in clusters

We found ... Cluster ... low frequency of ongoing mergers (~4%) ... signiﬁcant fraction of post mergers (~20%) ... post-merger galaxies preferentially locate in less dense regions (or cluster outskirts) z=0 position

Entry z=0.1 Merging z=0.3

Yi et al. (2013) Q. Then, are galaxy mergers important to the evolution of cluster galaxies? No Galaxy mergers have a limited inﬂuence on the present cluster population because only recently accreted galaxies would have a chance to show merger-induced changes Yes Galaxy clusters have accreted and will continue to accrete neighbouring galaxies. Therefore, galaxy mergers affect cluster population in the way of pre-processing Impact of Mergers on galaxy colours

Red Sequence Blue Red E Merger Normal A outskirts

S0 B

SE C

D SL

E center NUV - r - Red Sequence

NUV - r - Red Sequence Oh et al. in preparation KYDISC

Sample - Cluster Membership

Cluster membership Cluster velocity dispersion (σ) Virial radius (R200)

Carlberg et al. (1997)

Member criteria: M < -19.8 +/- 3σ Figure 3.4. (Continued). r R < 2R Figure 3.4. (Continued). 200 | rv - rvcen | < 3σ 49 Figure 3.4. (Continued). 1409 cluster galaxies 49

49 Visual morphology vs B/T or Asymmetry

Large FOV FOV = 4R90, different contrasts Ellipse Galfit color composite Large FOV FOV = 8R90, different contrasts Ellipse Galfit color composite Large FOV FOV = 8R90, different contrasts Ellipse Galfit color composite

Phase-Space Diagram

A outskirts

E center Image ﬁtting & modelling

• Ellipse ﬁt (IRAF) original model residual • Surface photometry • Effective radius, Position angle, Ellipticity

• GALFIT • Kim et al. (2016) • 2D bulge-disk decomposition • Bulge-to-total ratio (B/T)

Figure 3.6. Sample outputs from ellipse ﬁtting. The r0-band deep image, ellipse model, and residual image are shown in 1st, 2nd, and 3rd column in this ﬁgure.

53 The Ultraviolet (UV) Colour-Magnitude Relation

◇ merger

red-sequence (RS)

2σ below the RS

Oh et al. in preparation

Galaxies with merger features (diamonds) exhibit bluer color than non-merger galaxies, Figure 4.7. The composite NUV r CMR for each morphology. Solid and dashed especially in early morphology (E and0 S0). lines indicate the RS and the sequence 2 below the RS based on elliptical galaxies (E), respectively. Morphologically-disturbed galaxies which are denoted by diamonds show bluer color compared to undisturbed galaxies in the same morphology.