Neutral Hydrogen Content of Dwarf Galaxies in Different Environments

Abstract

Environments play an important role in galaxy formation and evolution, particularly in regulating the content of neutral gas. However, current H {\sc i} surveys have limitations in their depth, which prevents them from adequately studying low H {\sc i} content galaxies in high-density regions. In this study, we address this issue by employing the Five-hundred-meter Aperture Spherical radio Telescope (FAST) with extensive integration times to complement the relatively shallow Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) H {\sc i} survey. This approach allows us to explore the gas content of dwarf galaxies across various environments. 
We observe a positive relationship between H {\sc i} mass and stellar mass in dwarf galaxies, with a well-defined upper boundary for H {\sc i} mass that holds true in both observations and simulations. Furthermore, we find a decrease in the H {\sc i}-to-stellar mass ratio ($\rm M_{\rm HI}/M_*$) as the density of the environment increases, irrespective of whether it is determined by the proximity to the nearest group or the projected number density. Comparing our observations to simulations, we note a steeper slope in the relationship, suggesting a relatively slower gas-stripping process in observational data. Additionally, we find that the scaling relation between the $\rm M_{\rm HI}/M_*$ and optical properties can be improved by incorporating galaxy environments.