HI serves as the reservoir of material for galaxies to sustain their star formation and growth. We use spatially resolved interferometric data to develop methods that draw spatial information from unresolved global HI spectrum of galaxies, which are available for much larger samples than the interferometric data, and based on which our main studies are conducted. We estimate the HI mass within the optical radius of disk-dominated galaxies. We find that star formation rate (SFR) at a given stellar mass (M∗) is well correlated with the inner HI surface density (Sigma_HI,in). For the massive (M∗ > 10^10M_sun) disk galaxies, higher SFR at a given stellar mass is also related with higher efficiency of converting inner Hi to molecular gas, but no such correlation is found for the total HI mass. The highest Sigma_HI,in and the fastest depletion of the total neutral gas within the optical disks are found in the most compact and star-forming disk galaxies at a given stellar mass. These results highlight the important role of inner HI as an intermediate step of fueling star formation in disk-dominated galaxies.We classify the HI disks of HI-rich bulge-dominated galaxies into into settled (symmetric) and unsettled (asymmetric) types. We find that, the majority of centrally active (star-forming and/or hosting an active nuclei) ET galaxies are HI-rich, but HI-rich ET galaxies are not necessarily centrally active. Asymmetric HI disks are more likely to be centrally active, but at the same time they have similar global star formation rate and less HI compared to the symmetric ones. We hence do not find evidence for direct merger of satellite galaxies to be major source of gas accretion in gas-rich ET galaxies. Our results also suggest the difficulty of HI to flow in (in absence of strong torques like tidal interactions) and fuel the central (and inner) star formation of HI-rich early-type.
JW obtained her doctoral degree at USTC in 2011, and was postdoc at MPA and CSIRO-ATNF before taking a faculty job at KIAA in 2017. JW’s research interests are galaxy evolution in the low-redshift universe, particularly the atomic hydrogen (HI) gas, and the structure of disk galaxies. She has been actively involved in several large HI surveys, including (x-)GASS (and also its follow-up survey for molecular hydrogen, (x-)COLD GASS), Bluedisk, LVHIS, WALLABY, IMAGING, MALS.