Star-formation properties of Hickson Compact Groups based on deep H{\alpha} imaging

TL;DR

This study uses deep Hα imaging to analyze star formation in seven Hickson Compact Groups, revealing no enhanced star formation despite tidal features, and identifying a new tidal dwarf galaxy candidate.

Contribution

It provides high-resolution Hα observations of HCGs, analyzing star formation distribution, galaxy disk profiles, and identifying a new TDG candidate, which advances understanding of galaxy interactions.

Findings

No evidence of enhanced star formation in HCGs despite tidal features.

More massive galaxies have higher Hα light concentration.

Most previously identified TDG candidates are background objects.

Abstract

We present deep H{\alpha} imaging of seven Hickson Compact Groups (HCGs) using the 4.1m Southern Astrophysics Research (SOAR) Telescope. The high spatial resolution of the observations allow us to study both the integrated star-formation properties of the main galaxies as well as the 2D distribution of star-forming knots in the faint tidal arms that form during interactions between the individual galaxies. We derive star-formation rates and stellar masses for group members and discuss their position relative to the main sequence of star-forming galaxies. Despite the existence of tidal features within the galaxy groups, we do not find any indication for enhanced star-formation in the selected sample of HCGs. We study azimuthally averaged H{\alpha} profiles of the galaxy disks and compare them with the g' and r' surface-brightness profiles. We do not find any truncated galaxy disks but reveal that more massive galaxies show a higher light concentration in H{\alpha} than less massive ones. We also see that galaxies that show a high light concentration in r', show a systematic higher light concentration in H{\alpha}. TDG candidates have been previously detected in R-band images for 2 groups in our sample but we find that most of them are likely background objects as they do not show any emission in H{\alpha}. We present a new tidal dwarf galaxy (TDG) candidate at the tip of the tidal tail in HCG 91.