On the Correlation Between Atomic Gas and Bars in Galaxies

TL;DR

This study investigates how atomic gas content influences the size and strength of galactic bars, revealing that gas-rich galaxies tend to have longer, stronger bars, with different growth patterns depending on gas richness.

Contribution

It provides new insights into the relationship between atomic gas and bar evolution, highlighting distinct growth behaviors in gas-rich versus gas-poor galaxies.

Findings

Gas-rich galaxies have longer and stronger bars at fixed stellar mass.

Bar size depends on stellar mass but not significantly on HI gas fraction.

Different bar growth patterns are observed in gas-rich and gas-poor galaxies.

Abstract

We analyze the correlation between properties of large-scale bars and atomic gas content of galaxies to explore the role of HI gas on bar evolution in galaxies. We show that the absolute bar size depends strongly on total stellar mass of galaxies and does not change significantly with HI gas fraction at fixed stellar mass. Furthermore, the physical size of the bar is small and nearly constant in high Hi gas fraction and low-mass galaxies, and becomes larger with increasing galactic stellar mass in low gas fraction galaxies. When the stellar masses are fixed, the relative bar length normalized to the disk shows a decrease with increasing HI gas fraction due to the larger disks in gas-richer galaxies. We measure the gas deficiency of the samples and find that the gas-rich galaxies have longer and stronger bars compared with the Hi gas-deficient galaxies at fixed stellar mass, especially for the massive ones. When splitting the samples into star forming and quiescent subgroups, the star forming galaxies tend to have longer bars than the quiescent ones at fixed stellar mass and gas deficiency. In addition, our results suggest two different types of bar properties, in which the bars in gas-rich galaxies grow longer but retain similar axial ratio over time, while they grow longer and fatter over time in gas-poor galaxies.