The Galaxy Population of the Core of Coma Cluster

TL;DR

This study analyzes the structural properties and morphology of galaxies in the Coma Cluster's core, revealing correlations between galaxy parameters and insights into their merger history using HST data.

Contribution

It provides a detailed morphological and structural analysis of Coma Cluster galaxies, including bulge-disc decomposition and parameter correlations, with a focus on galaxy classification and cluster membership.

Findings

More E/SO and ESO galaxies are cluster members than non-members.

Significant correlations between $B/T$, color, and Sersic index.

Identification of galaxies with boxy/peanut bulges.

Abstract

In this paper we present the structural properties and morphology of galaxies in the central region of the Coma Cluster brighter than $19.5^m$ in the $F814W$ band. from the HST/ACS Coma Cluster Treasury Survey. Using mainly spectroscopic redshifts, we find 132 members from our sample of 219 galaxies. In our sample of 132 members, we find 51 non-dwarfs and 81 dwarfs and amongst our 32 non-members, we find 4 dwarfs and 28 non dwarfs. We do not have redshifts for the remaining 55 galaxies. We present bulge-disc decomposition of the sample using GALFIT and obtain parameters for our sample. Using visual inspection of residuals, we do a a morphological classification of the galaxies. We studied the relation of morphological types with Bulge to Total Light Ratio ($B/T$), color magnitude relation (CMR), S\'ersic index ($n$), Kormendy relation and cross-correlations between these parameters for the bulges and galaxies. %Of the members, six galaxies have been classified as E/SBO on the basis of their residuals and contour maps which show a boxy/peanut bulge at the center of galaxy. So we have little confusion to classify the elliptical or SBO, we have given E/SBO. This work helps us understand important relations between various parameters like $B/T$, color and $n$ as well as insights into the merger history of these galaxies in terms of their positions in the Kormendy Diagram and their S\'ersic indices. Using statistical methods, we find that the there are significantly more E/SO, ESOs galaxies in the member population compared to non-members.