Star-formation properties of Hickson Compact Groups based on deep Hα imaging

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.