The bright galaxy population of five medium redshift clusters. II. Quantitative Galaxy Morphology

TL;DR

This study analyzes the surface brightness profiles of bright galaxies in five medium redshift clusters, revealing that their disc scales differ from those in similar low-redshift cluster galaxies and are comparable to nearby field galaxies, indicating faster disc evolution in clusters.

Contribution

It provides a quantitative morphological analysis of galaxy structures in medium redshift clusters, highlighting differences in disc scales and suggesting rapid evolutionary processes.

Findings

Disc scales in medium redshift cluster galaxies differ from low-redshift cluster galaxies.

Disc scales in medium redshift clusters are similar to nearby field galaxies.

Galaxy harassment may drive rapid disc evolution in clusters.

Abstract

Aims: Following the study already presented in our previous paper, based on the Nordic Optical Telescope (NOT) sample, which consists of five clusters of galaxies within the redshift range 0.18 $\leq$ z $\leq$ 0.25, imaged in the central 0.5-2 Mpc in very good seeing conditions, we have studied the quantitative morphology of their bright galaxy population Methods: We have analyzed the surface brightness profiles of the galaxy population in those clusters. Previously, we have performed simulations in order to check the reliability of the fits. We have also derived a quantitative morphological classification. Results: The structural parameters derived from these analysis have been analyzed. We have obtained that the structural parameters of E/S0 galaxies are similar to those showed by galaxies in low redshift clusters. However, the disc scales are different. In particular, the scales of the discs of galaxies at medium redshift clusters are statistically different than those located in similar galaxies in the Coma cluster. But, the scales of the discs of galaxies in medium redshift clusters are similar to nearby field galaxies. Conclusions: The results suggest that the evolution of the disc component of galaxies in clusters is faster than in field ones. Mechanisms like galaxy harassment showing timescales of $\sim 1$Gyr could be the responsible of this disc scale evolution. This indicates that spiral galaxies in clusters have suffered a strong evolution in the last 2.5 Gyr or that Coma is in some way anomalous.