Physical properties of SDSS satellite galaxies in projected phase space

Abstract

We investigate how environment affects satellite galaxies using their location within the projected phase space of their host haloes from the Wang et al.'s group catalogue. Using the Yonsei Zoom-in Cluster Simulations, we derive zones of constant mean infall time \overline{T}_inf in projected phase space, and catalogue in which zone each observed galaxy falls. Within each zone, we compute the mean observed galaxy properties including specific star formation rate, luminosity-weighted age, stellar metallicity, and [α/Fe] abundance ratio. By comparing galaxies in different zones, we inspect how shifting the mean infall time from recent infallers (\overline{T}_inf < 3 Gyr) to ancient infallers (\overline{T}_{inf}> 5 Gyr) impacts galaxy properties at fixed stellar and halo mass. Ancient infallers are more quenched, and the impact of environmental quenching is visible down to low host masses (≤group masses). Meanwhile, the quenching of recent infallers is weakly dependent on host mass, indicating they have yet to respond strongly to their current environment. [α/Fe] and especially metallicity are less dependent on host mass, but show a dependence on \overline{T}_{inf}. We discuss these results in the context of longer exposure times for ancient infallers to environmental effects, which grow more efficient in hosts with a deeper potential well and a denser intracluster medium. We also compare our satellites with a control field sample, and find that even the most recent infallers (\overline{T}_{inf} < 2 Gyr) are more quenched than field galaxies, in particular for cluster mass hosts. This supports the role of pre-processing and/or faster quenching in satellites.