Environments and morphologies of red sequence galaxies with residual star formation in massive clusters

Crossett, Jacob P. and Pimbblet, Kevin A. and Stott, John P. and Jones D. Heath, D. H. (2014) Environments and morphologies of red sequence galaxies with residual star formation in massive clusters. Monthly Notices of the Royal Astronomical Society, 437 (3). pp. 2521-2530. ISSN 0035-8711

Abstract

We present a photometric investigation into recent star formation in galaxy clusters at z ~ 0.1. We use spectral energy distribution templates to quantify recent star formation in large Xray- selected clusters from the LARCS survey using matched GALEX near-ultraviolet (NUV) photometry. These clusters all have signs of red sequence galaxy recent star formation (as indicated by the blue NUV - R colour), regardless of the cluster morphology and size. A trend in environment is found for these galaxies, such that they prefer to occupy low-density, highcluster- radius environments. The morphology of these UV-bright galaxies suggests that they are in fact red spirals, which we confirm with light profiles and Galaxy Zoo voting percentages as morphological proxies. These UV-bright galaxies are therefore seen to be either truncated spiral galaxies, caught by ram pressure infalling into the cluster, or high-mass spirals, with the photometry dominated by the older stellar population.