Satellite Quenching and Structural Change Joanna Woo ETH Zürich With M. Carollo S. Faber A. Dekel S. Tacchella Et al.

What we know about quenching so far Studies in quenching reveal correlations between: Morphology and quenching

What we know about quenching so far Studies in quenching reveal correlations between: Morphology and quenching Morphology and environment

What we know about quenching so far Studies in quenching reveal correlations between: Morphology and quenching Morphology and environment Environment (Mhalo) and quenching Σ1kpc Woo et al. (2015) Mhalo

What we know about quenching so far Studies in quenching reveal correlations between: Morphology and quenching Environment (Mhalo) and quenching Morphology and environment Question: Does the halo environment induce morphological/structural change during satellite quenching?

Satellites vs. the Field Structure/Morphology - light within circular annuli in 5 bands → M/L (KCORRECT) - PSFWIDTH < 1kpc - strongest predictor of quenching → physical scale of mechanism? Brinchmann et al., (2004) Entire distribution contains more information than quenched fraction (Woo et al., 2015)

Satellites vs. the Field Woo et al., in preparation

Woo et al., in preparation

All Masses Woo et al., in preparation

All Masses Woo et al., in preparation

Satellite Quenching Depends on Environment Woo et al., (2013)

Satellite Quenching vs. Environment Woo et al., in preparation

Difficulties with Interpretation: Progenitors Mass growth after quenching (accretion cut-off) Cold gas content needs to be significant: high z High-z progenitors from a lower mass bin will be quenched by now Mass loss after quenching Stellar aging and death For satellites: stripping of mass can be significant Timing of infall vs quenching Degeneracy between assembly history of haloes and actual physical quenching In light of these difficulties, what can we learn about structural change during quenching?

Does the Halo Environment Induce Structural Change During Satellite Quenching? Assumption: GV galaxies are currently quenching and are drawn from the SF population Currently quenching satellites: drawn from the whole range of Σ1kpc Currently quenching field galaxies: drawn only from the highest tip of Σ1kpc Thus the answer seems to be “No” for currently quenching satellites.

Physical Mechanisms Current satellite quenching: Independent of Σ1kpc Driven by massive halo, not group- centric distance Candidates: Starvation due to stripping of hot gas or cut-off of accretion Ram pressure stripping of cold gas

Physical Mechanisms Less massive haloes: less likely to experience ram pressure or starvation; can be affected by tides Tidally triggered starburst? But SFR not enhanced Tidal compression? But not enough time at pericentre These do not quench satellites, only change structure Complete disruption? But ratios seems not to have changed.

Summary of Findings Possible Interpretation GV “bridge” for satellites has lower Σ1kpc Main sequence (and quenched seq.) of satellites is lower than the field Differences between field and satellites disappears at high M* Differences driven mainly by high Mh Group-centric distance affects Σ1kpc distribution of SF satellites in low- mass haloes Currently quenching satellites quench at all Σ1kpc in contrast to currently quenching isolated galaxies Very little to no change in structure during quenching Satellite quenching in massive haloes: ram pressure or starvation Tidal processes: only in less massive haloes, probably don't quench Possible Interpretation