Mid-Infrared Evidence for Accelerated Evolution in Compact Group Galaxies

TL;DR

This study provides mid-infrared evidence that galaxies in compact groups evolve faster than those in other environments, showing distinct color distributions and a unique gap in their infrared colorspace.

Contribution

It demonstrates that compact group galaxies have a unique mid-infrared color distribution, indicating accelerated evolution compared to other galaxy environments.

Findings

Compact group galaxies show a non-uniform color distribution.

Presence of a gap in the mid-infrared colorspace of HCG galaxies.

The gap is potentially unique to high-density galaxy environments.

Abstract

We find evidence for accelerated evolution in compact group galaxies from the distribution in mid-infrared colorspace of 42 galaxies from 12 Hickson Compact Groups (HCGs) compared to the the distributions of several other samples including the LVL+SINGS galaxies, interacting galaxies, and galaxies from the Coma Cluster. We find that the HCG galaxies are not uniformly distributed in colorspace, as well as quantitative evidence for a gap. Galaxies in the infall region of the Coma cluster also exhibit a non-uniform distribution and a less well defined gap, which may reflect a similarity with the compact group environment. Neither the Coma Center or interacting samples show evidence of a gap, leading us to speculate that the gap is unique to the environment of high galaxy density where gas has not been fully processed or stripped.