Australia Telescope National Facility

Jing Wang Colloquium: The Formation and Evolution of Galactic Disks with Gas Accretion and Inflow

Abstract

Most galaxies in the local universe evolve in the secular mode, and the processes are almost always accompanied by obtaining or losing of cold gas. The correlation between the color gradients and gas fraction in galaxies supports the picture of gas accretion driven inside-out galactic disk formation. The regular morphologies in the optical and HI for the HI-rich galaxies suggest the gas accretion is accreted in a slow and gentle way. The brightest cluster galaxies (BCG) are as old as galaxies of the same stellar masses, suggesting that the location of centre of dark matter halo does not guarantee gas accretion. The gas ``conformity'' phenomenon for central and satellite galaxies supports the picture of cold accretion in galaxies with intermediate masses.
Only strong bars induce significant gas inflow, and around half of the galaxies with a central starburst host strong bars. Strong bars are also connected with galaxies with suppressed star formation, suggesting a self-regulated way of galactic disc evolution.