On the Interaction in a Quartet of Galaxies

TL;DR

This study uses Fabry-Perot interferometry to analyze the velocity fields of a galaxy quartet, revealing how interactions distort their rotation curves and morphological features, indicating their interaction stages.

Contribution

It provides detailed velocity field measurements and analysis of interaction effects in a specific galaxy quartet, highlighting the dynamical consequences of galaxy flybys.

Findings

NGC 7769's rotation curve is weakly distorted

NGC 7771's rotation curve is strongly distorted by tidal interactions

NGC 7770's rotation curve is significantly skewed due to interaction

Abstract

We performed the Fabry-Perot scanning interferometry of the quartet of galaxies NGC 7769, 7770, 7771 and 7771A in Ha line and studied their velocity fields. We found that the rotation curve of NGC 7769 is weakly distorted. The rotation curve of NGC 7771 is strongly distorted with the tidal arms caused by direct flyby of NGC 7769 and flyby of a smaller neighbor NGC 7770. The rotation curve of NGC 7770 is significantly skewed because of the interaction with much massive NGC 7771. The rotation curves and morphological disturbances suggest that the NGC 7769 and NGC 7771 have passed the first pericenter stage, however, probably the second encounter has not happened yet.