YZiCS: Unveiling Quenching History of Cluster Galaxies Using Phase-space
  Analysis
  We used the time since infall (TSI) of galaxies, obtained from the Yonsei
Zoom-in Cluster Simulation, and the star formation rate (SFR) from the Sloan
Digital Sky Survey (SDSS) Data Release 10 to study how quickly star formation
of disk galaxies is quenched in cluster environments. We first confirm that
both simulated and observed galaxies are consistently distributed in phase
space. We then hypothesize that the TSI and SFR are causally connected; thus,
both the TSI and SFR of galaxies at each position of phase space can be
associated through abundance matching. Using a flexible model, we derive the
star formation history (SFH) of cluster galaxies that best reproduces the
relationship between the TSI and SFR at $z\sim 0.08$. According to this SFH, we
find that the galaxies with $M_{*} > 10^{9.5} M_{\odot}$ generally follow the
so-called "delayed-then-rapid" quenching pattern. Our main results are as
following: (i) Part of the quenching takes place outside clusters through mass
quenching and pre-processing. The e-folding timescale of this "$ex\text{-}situ$
quenching phase" is roughly 3 Gyr with a strong inverse mass dependence. (ii)
The pace of quenching is maintained roughly for 2 Gyr ("delay time") during the
first crossing time into the cluster. During the delay time, quenching remains
gentle probably because gas loss happens primarily on hot and neutral gases.
(iii) Quenching becomes more dramatic (e-folding timescale of roughly 1 Gyr)
after delay time, probably because ram pressure stripping is strongest near the
cluster center. Counter-intuitively, more massive galaxies show shorter
quenching timescales mainly because they enter their clusters with lower gas
fractions due to $ex\text{-}situ$ quenching.
