The SAMI Galaxy Survey: A Range in S0 Properties Indicating Multiple Formation Pathways

Abstract

It has been proposed that S0 galaxies are either fading spirals or the result of galaxy mergers. The relative contribution of each pathway, and the environments in which they occur remains unknown. Here we investigate stellar and gas kinematics of 219 S0s in the SAMI Survey to look for signs of multiple formation pathways occurring across the full range of environments. We identify a large range of rotational support in their stellar kinematics, which correspond to ranges in their physical structure. We find that pressure-supported S0s with $v/\sigma$ below 0.5 tend to be more compact and feature misaligned stellar and gas components, suggesting an external origin for their gas. We postulate that these S0s are consistent with being formed through a merger process. Meanwhile, comparisons of ellipticity, stellar mass and Sérsic index distributions with spiral galaxies shows that the rotationally supported S0s with $v/\sigma$ above 0.5 are more consistent with a faded spiral origin. In addition, a simulated merger pathway involving a compact elliptical and gas-rich satellite results in an S0 that lies within the pressure-supported group. We conclude that two S0 formation pathways are active, with mergers dominating in isolated galaxies and small groups, and the faded spiral pathway being most prominent in large groups ($10^{13}<M_{halo}<10^{14}$).

14 pages, 12 figures, accepted for publication in MNRAS

References in corpus (17)

• The SAURON project -- IX. A kinematic classification for early-type galaxies
• The SAURON project -- X. The orbital anisotropy of elliptical and lenticular galaxies: revisiting the (V/sigma,epsilon) diagram with integral-field stellar kinematics
• The SAMI Galaxy Survey: instrument specification and target selection
• The SAMI Galaxy Survey: the link between angular momentum and optical morphology
• The SAMI Galaxy Survey: Revisiting Galaxy Classification Through High-Order Stellar Kinematics
• The SAMI Galaxy Survey: Early Data Release
• ProFit: Bayesian Profile Fitting of Galaxy Images
• The SAMI Galaxy Survey: Cubism and covariance, putting round pegs into square holes
• LZIFU: an emission-line fitting toolkit for integral field spectroscopy data
• The SAMI Galaxy Survey: Quenching of star formation in clusters I. Transition galaxies
• The SAMI Galaxy Survey: Data Release One with Emission-line Physics Value-Added Products
• The Origin of S0s in Clusters: evidence from the bulge and disc star formation histories
• Untangling galaxy components: full spectral bulge-disc decomposition
• Formation of S0 galaxies through mergers. Evolution in the Tully-Fisher relation since $z\sim 1$
• The SAMI Galaxy Survey: Satellite galaxies undergo little structural change during their quenching phase
• Formation of S0s in extreme environments I: clues from kinematics and stellar populations
• Ionized gas disks in elliptical and S0 galaxies at $z<1$

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• The local Universe in the era of large surveys -- II. Multi-wavelength characterisation of activity in nearby S0 galaxies
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