Evolution of Galaxy Types and HI Gas in Hickson Compact Groups

TL;DR

This study investigates how galaxy types and HI gas content evolve in Hickson Compact Groups, revealing correlations between group crossing time, galaxy morphology, and star formation activity, thus shedding light on galaxy evolution in dense environments.

Contribution

It provides new insights into the relationship between group crossing time, galaxy morphology, and HI content in compact groups, using extensive data analysis from multiple surveys.

Findings

Weak correlation between HI mass fraction and crossing time.

Group spiral fraction correlates with crossing time.

Star-forming galaxy fraction shows no correlation with crossing time.

Abstract

Compact groups have high galaxy densities and low velocity dispersions, and their group members have experienced numerous and frequent interactions during their lifetimes. They provide a unique environment to study the evolution of galaxies. We examined the galaxies types and HI contents in groups to make a study on the galaxy evolution in compact groups. We used the group crossing time as an age indicator for galaxy groups. Our sample is derived from the Hickson Compact Group catalog. We obtained group morphology data from the Hyper-Leda database and the IR classification based on Wide-Field Infrared Survey Explorer (WISE) fluxes from Zucker et al. (2016). By cross-matching the latest released ALFALFA 100% HI source catalog and supplemented by data found in literature, we obtained 40 galaxy groups with HI data available. We confirmed that the weak correlation between HI mass fraction and group crossing time found by Ai & Zhu (2018) in SDSS groups also exists in compact groups. We also found that the group spiral galaxy fraction is correlated with the group crossing time, but the actively star-forming galaxy fraction is not correlated with the group crossing time. These results seem to fit with the hypothesis that the sequential acquisition of neighbors from surrounding larger-scale structures has affected the morphology transition and star formation efficiency in compact groups.