Title:Gas accretion and the subsequent evolution of disc galaxies

Speaker:Prof. Jing Wang (KIAA)

Date:Thursday, June 20, 2019, 02:00pm

Venue:South 727, Mong Man-wai Science Technology Building


Abstract:We search for footprints of gas accretion in and around HI-rich massive galaxies with data collected in the Bluedisk project. The HI-rich galaxies tend to have an HI-rich environment, suggesting a large-scale fueling. We find the excess HI has two types of radial distributions in HI-rich galaxies, suggesting two types of gas accretion, possibly corresponding to the fountain mechanism and cosmological accretion. We investigate how disk galaxies evolve with the accreted gas. The growth of discs are tightly corelated with the total amount of HI gas, and the effect can extend to large radius, well beyond the disk breaks. Bars drive strong gas inflows and enhance central SFR in most of the barred galaxies, however, they do not always do so even when plenty of HI is available. The details could depend on the radial distribution of HI and dynamical properties of the bars. Finally, the growth of bulges are not directly related with the HI gas, no matter whether they are pseudo or classical, and no matter whether the galaxies are interacting or hosting bars.