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

Abstract

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 $\mathord {\sim }4$ deg2. We increase the number of LSB galaxies presented in Yagi et al. (2016) by a factor of $\mathord {\sim }3$ and report the discovery of 29 new ultradiffuse galaxies (UDGs). We compile the largest sample of UDGs with colours and structural parameters in the Coma cluster. While most UDGs lie along the red-sequence relation of the colour–magnitude diagram, $\mathord {\sim }16$ per 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 $\mathord {\sim }0.6$ Mpc. Within this cluster core region and relative to the red-sequence of galaxies, LSB galaxies are on average redder than co-spatial higher surface brightness galaxies at the 2σ level, 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.