Barred Galaxies in the Coma Cluster

TL;DR

This study analyzes the properties and frequency of barred galaxies in the dense core of the Coma cluster using HST data, revealing a high optical bar fraction among S0 galaxies and environmental influences on bar sizes.

Contribution

It provides the first detailed analysis of barred galaxy properties specifically in the Coma cluster core, highlighting environmental effects on bar fractions and sizes.

Findings

Optical bar fraction for S0s is approximately 47%.

No very large bars (>2 kpc) are found in the core.

Bar fraction is higher in the dense Coma environment compared to less dense regions.

Abstract

We use ACS data from the HST Treasury survey of the Coma cluster (z~0.02) to study the properties of barred galaxies in the Coma core, the densest environment in the nearby Universe. This study provides a complementary data point for studies of barred galaxies as a function of redshift and environment. From ~470 cluster members brighter than M_I = -11 mag, we select a sample of 46 disk galaxies (S0--Im) based on visual classification. The sample is dominated by S0s for which we find an optical bar fraction of 47+/-11% through ellipse fitting and visual inspection. Among the bars in the core of the Coma cluster, we do not find any very large (a_bar > 2 kpc) bars. Comparison to other studies reveals that while the optical bar fraction for S0s shows only a modest variation across low-to-intermediate density environments (field to intermediate-density clusters), it can be higher by up to a factor of ~2 in the very high-density environment of the rich Coma cluster core.