The environment and accretion history of the galaxy cold gas component

Abstract:

  In this talk, I’ll introduce our recent results on the dark matter halo environment of the galaxy neutral hydrogen gas using both the observation and hydrodynamical simulations. By using the ALFALFA sample of the HI 21cm observation of the local galaxies, we found that the HI-rich galaxies live in under dense environment, especially in low-mass and recently formed halos. We use the state-of-art IllustrisTNG hydrodynamical simulations to further study the environment of the gas-rich galaxies and confirm our results using the ALFALFA sample. We find that most of the cold gas in the observed HI-rich galaxies is recently accreted into their host halos. The star-formation history of the gas-rich galaxies are also affected by the halo accretion history.