A Statistical Study of H I Gas in Nearby Narrow-Line AGN-Hosting Galaxies

TL;DR

This study investigates the relationship between HI gas content and AGN activity in nearby galaxies, finding no significant impact of AGN activity on HI mass or gas-to-stellar mass ratio, despite AGN-hosting galaxies being gas-rich.

Contribution

It provides the first analysis of HI mass dependence on AGN activity in a large galaxy sample, revealing that AGN activity does not significantly alter HI content.

Findings

AGN-hosting galaxies are predominantly gas-rich.

No evidence that AGN activity affects HI mass or ratio.

Similar star formation histories in AGN-hosting and non-AGN galaxies.

Abstract

As a quenching mechanism, AGN feedback could suppress on-going star formation in their host galaxies. On the basis of a sample of galaxies selected from ALFALFA HI survey, the dependence of their HI mass M[HI], stellar mass M[*] & HI-to-stellar mass ratio M[HI]/M[*] on various tracers of AGN activity are presented and analyzed in this paper. Almost all the AGN-hostings in this sample are gas-rich galaxies, and there is no any evidence to be shown to indicate that the AGN activity could increase/decrease either M[HI] or M[HI]/M[*]. The cold neutral gas can not be fixed positions accurately just based on available HI data due to the large beam size of ALFALFA survey. In addition, even though AGN-hostings are more easily detected by HI survey compared with absorption line galaxies, these two types of galaxies show similar star formation history. If an AGN-hosting would ultimately evolve into an old red galaxy with few cold gas, then when and how the gas has been exhausted have to be solved by future hypotheses and observations.