Oral Presentation

Unveiling quenching history of cluster/group galaxies using phase-space analysis

Author(s): Jinsu, Rhee (Yonsei University); Sukyoung, K. Yi (Yonsei University) et al.

Presenter: Jinsu Rhee (Yonsei University)

Combining with the orbital library of cluster galaxies from the latest cosmological N-body simulations, we derive the star formation rate (SFR) vs. time since infall (TSI) relation of cluster galaxies of the Sloan Digital Sky Survey (SDSS) Data Release 10 to study how quickly star formation of disk galaxies is quenched in cluster environments.
The main strategy is to causally connect the properties of observed galaxies and simulated galaxies that are located at the same position of phase-space through abundance matching.
We then constrain the formulated star formation history (SFH) of cluster galaxies that best reproduces the derived relationship between the TSI and SFR.
According to the constrained SFH, the galaxies generally follows the so-called delayed-then-rapid quenching pattern, mainly showing that quenching becomes dramatic (e-folding timescale of roughly 1 Gyr) after delay time (~ 2 Gyr, comparable to the first crossing timescale).
Counterintuitively, the constrained SFH also implies that the mass-quenching of galaxies (~ 4 Gyr) that happened before they enter their clusters is also an important factor in determining the quenching timescale of cluster galaxies.
Our follow-up study extends the sample in a group-size host and derives their SFH using the same method above to infer how smoothly/dramatically the quenching pattern depends on the host mass.