An expanded catalogue of low surface brightness galaxies in the Coma cluster using Subaru/Suprime-Cam

TL;DR

This study provides a comprehensive catalogue of low surface brightness galaxies in the Coma cluster, including new ultra-diffuse galaxies, and analyzes their properties and distribution within the cluster environment.

Contribution

It expands the known sample of LSB galaxies in Coma by threefold, reports new UDG discoveries, and investigates their spatial and color distribution in relation to cluster dynamics.

Findings

Most UDGs are on the red sequence, with some outliers.

LSB galaxies are redder near the cluster center, indicating environmental effects.

The transition radius at 0.6 Mpc aligns with cosmological simulation predictions.

Abstract

We present a catalogue of low surface brightness (LSB) galaxies in the Coma cluster obtained from deep Subaru/Suprime-Cam V and R-band imaging data within a region of $\sim$4 deg$^2$. We increase the number of LSB galaxies presented in Yagi et al. (2016) by a factor of $\sim$3 and report the discovery of 29 new ultra-diffuse galaxies (UDGs). We compile the largest sample of ultra-diffuse galaxies with colours and structural parameters in the Coma cluster. While most UDGs lie along the red-sequence relation of the colour-magnitude diagram, $\sim$5per cent are outside (bluer or redder) the red-sequence region of Coma cluster galaxies. Our analyses show that there is no special distinction in the basic photometric parameters between UDGs and other LSB galaxies. We investigate the clustercentric colour distribution and find a remarkable transition at a projected radius of $\sim$0.6 Mpc. Within this cluster core region, LSB galaxies are, on average, redder than co-spatial higher surface brightness galaxies, highlighting how vulnerable LSB galaxies are to the physical processes at play in the dense central region of the cluster. The position of the transition radius agrees with expectations from recent cosmological simulation of massive galaxy clusters within which ancient infalls are predicted to dominate the LSB galaxy population.