The Tully-Fisher relations for Hickson Compact Group galaxies

TL;DR

This study examines the Tully-Fisher relations for Hickson compact group galaxies using K-band, stellar, and baryonic data, revealing most align with field galaxy relations but some are affected by starbursts and AGN activity.

Contribution

First analysis of K-band, stellar, and baryonic Tully-Fisher relations specifically for Hickson compact group galaxies, comparing them with less dense environment galaxies.

Findings

Most Hickson galaxies follow the field galaxy Tully-Fisher relation.

Starburst and AGN activity can brighten galaxy luminosities, affecting their position on the relation.

Including gaseous mass reduces scatter in the baryonic Tully-Fisher relation.

Abstract

We used K-band photometry, maximum rotational velocities derived from Fabry-Perot data and HI observed and predicted masses to study, for the first time, the K-band, stellar and baryonic Tully-Fisher relations for galaxies in Hickson compact groups. We compared these relations with the ones defined for galaxies in less dense environments from the GHASP survey and from a sample of gas-rich galaxies. We find that most of the Hickson compact group galaxies lie on the K-band Tully-Fisher relation defined by field galaxies with a few low-mass outliers, namely HCG 49b and HCG 96c, which appear to have had strong recent burst of star formation. The stellar Tully-Fisher relation for compact group galaxies presents a similar dispersion to that of the K-band relation, and it has no significant outliers when a proper computation of the stellar mass is done for the strongly star-forming galaxies. The scatter in these relations can be reduced if the gaseous component is taken into account, i.e., if a baryonic Tully-Fisher relation is considered. In order to explain the positions of the galaxies off the K-band Tully-Fisher relation we favour a scenario in which their luminosities are brightened due to strong star formation or AGN activity. We argue that strong bursts of star formation can affect the B and K-band luminosities of HCG 49b and HCG 96c and in the case of the latter also AGN activity may affect the K-band magnitude considerably, without affecting their total masses.