Mass Distribution in Hickson Compact Groups of Galaxies

TL;DR

This paper investigates the mass distribution in late-type galaxies within Hickson Compact Groups, comparing dark matter halo profiles and their relation to galaxy environment and type, using high-resolution observations.

Contribution

It provides a comparative analysis of dark halo profiles in compact group galaxies versus field and cluster galaxies, highlighting the preference for core-like profiles.

Findings

Core-like profiles fit rotation curves better than cuspy profiles.

Halo surface density is constant across galaxy magnitudes.

No significant difference in halo profiles among different environments.

Abstract

This study presents the mass distribution for a sample of 18 late-type galaxies in nine Hickson Compact Groups. We used rotation curves from high resolution 2D velocity fields of Fabry-Perot observations and J-band photometry from the 2MASS survey, in order to determine the dark halo and the visible matter distributions. The study compares two halo density profile, an isothermal core-like distribution and a cuspy one. We also compare their visible and dark matter distributions with those of galaxies belonging to cluster and field galaxies coming from two samples: 40 cluster galaxies of Barnes et al (2004) and 35 field galaxies of Spano et al. (2008). The central halo surface density is found to be constant with respect to the total absolute magnitude similar to what is found for the isolated galaxies. This suggests that the halo density is independent to galaxy type and environment. We have found that core-like density profiles fit better the rotation curves than cuspy-like ones. No major differences have been found between field, cluster and compact group galaxies with respect to their dark halo density profiles.