Oral Presentation
Unveiling Quenching History of Cluster Galaxies Using Phase-space Analysis
Presenter: Jinsu Rhee (Yonsei Univ.)
We utilize times since infall of cluster galaxies obtained from Yonsei Zoom-in Cluster Simulation (YZiCS), the cosmological hydrodynamic N -body simulations, and star formation rates from the SDSS data release 10 to study how quickly late-type galaxies are quenched in the cluster environments. In particular, we confirm that the distributions of both simulated and observed galaxies in phase-space diagrams are comparable and that each location of phase-space can provide the information of times since infall and star formation rates of cluster galaxies. Then, by limiting the location of phase-space of simulated and observed galaxies, we associate their star formation rates at z ∼ 0 with times since infall using an abundance matching technique that employs the quantiles of each probability distribution. Using a flexible quenching model covering different quenching scenarios, we find the star formation history of satellite galaxies that best reproduces the obtained relationship between time since infall and star formation rate at z ∼ 0. Based on the derived star formation history, we constrain the quenching timescale (3-5Gyr) and confirm that the refined model is consistent with the "delayed-then-rapid" quenching scenario: the constant delayed phase as ∼ 3Gyr and the quenching efficiencies (i.e., e- folding timescale) outside and inside clusters as ∼ 5 Gyr and 0.5 - 1.0 Gyr, respectively, varying with stellar mass. Finally, we suggest: (i) environmental quenching in clusters play a role on galaxies' SFRs, (ii) massive galaxies show a sign of internal quenching process at high redshift, (iii) we provide the time since infall data that we have used in the abundance matching, which can be utilized in other work studying on the cluster environmental effects with time since infall, especially.
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