Galaxy evolution in dense environments: the gaseous view
气体视角下致密环境中的星系演化
The environment where galaxies reside largely determines their evolution. In denser environments, galaxies generally have redder colour and more quiescent star-formation activity. As the major ingredient of star formation and a sensitive tracer of both feedback and environmental processes, the gas in galaxy can provide valuable information on the galaxy evolution. In this talk, I will review recent surveys that trace the galaxy evolution in dense environments by observing gaseous component in different phases, such as VESTIGE, GASP, and the MeerKAT Fornax Survey. High-quality and abundant data provide interesting individual cases. Most importantly, statistical studies on the galaxies in single structure with a rather simple source selection become possible. It has been confirmed that ram-pressure stripping has dominating roles in high-density clusters; in less massive groups, however, the details of the quenching processes are still unclear due to the entanglement between different possible mechanisms, such as tidal stripping (harassment), thermal evaporation, and starvation. Several studies have managed to model the gas stripping process and estimate the relevant time scales in individual clusters or groups, but a larger sample is required for concrete conclusions.
