Reduction of bar fraction in paired galaxies in the SDSS

TL;DR

This study shows that galaxy interactions, especially major mergers, tend to suppress bar structures in galaxies, with the effect being more pronounced in massive galaxies and primarily affecting weak bars.

Contribution

It provides observational evidence that tidal interactions in galaxy pairs, particularly major mergers, suppress bar formation, especially weak bars, in a mass-dependent manner.

Findings

Bar fraction decreases in close galaxy pairs within 25 kpc.

Major mergers significantly suppress bar structures, especially weak bars.

Suppression is more evident in massive galaxies with small bulges.

Abstract

We investigate the bar fraction in galaxy pairs from the SDSS to assess how galaxy interactions affect bar structures. Compared to isolated galaxies, close pairs exhibit a significantly reduced bar fraction at projected separations within 25 kpc. This reduction is driven almost entirely by systems showing clear merger or disturbance signatures, indicating that tidal interactions suppress bars. The decline is dominated by a decrease in weak bars, while the fraction of strong bars remains largely unchanged. Bar suppression is primarily associated with major mergers and is strongest in massive host galaxies. A weaker but statistically significant suppression is detected in minor mergers only for massive galaxies with small bulges. In contrast, no significant dependence of bar suppression on the relative orientation between pair members is found. These findings provide observational evidence that tidal perturbations in major mergers play a key role in regulating bar evolution.