Description

Meeting ID: 523 477 035

Joining Link：https://zoom.com.cn/j/523477035

Speaker:Prof. Huiyuan Wang (USTC)

Huiyuan is a professor at Department of Astronomy in University of Science and Technology of China. He got his PhD degree in 2006 from USTC, then worked in USTC and University of Massachusetts Amherst as a postdoc. His research interests include large scale structure, galaxy formation and AGN.

Abstract: Based on SDSS galaxy sample, we identify a clear transition feature of galaxy quenching in the multi-parameter space of stellar mass(M*), bulge to total mass ratio (B/T), halo mass(Mh) and halo-centric distance(r/r180). For given halo mass, the characteristic stellar mass (Mch) for the transition is about one-fifth of that of the corresponding central galaxy, and almost independent of galaxy morphology. Once B/T is fixed, the quenched fraction of galaxies with M*0.5), the trend with halo mass remains but the correlation with stellar mass is absent or becomes positive. For galaxies above Mch and with B/T fixed, the quenched fraction increases with stellar mass, but depends only weakly on halo mass in both the inner and outer regions. At fixed B/T and M*, the quenched fraction increases with decreasing r/r180 for galaxies with M*<Mch, and is almost independent r/r180 for galaxies with M*>Mch. Our finding provides a physically-motivated way to classify galaxies in halos into two classes based on their quenching properties: an `upper class' with M*>Mch} and a `lower class' with M*<Mch$. Environmental quenching is important only for `lower class' galaxies, while internal quenching plays the dominating role for the `upper class'.