Using theXMM-NewtonOptical Monitor to Study Cluster Galaxy Evolution

Abstract

ABSTRACT. We explore the application of XMM-Newton Optical Monitor (XMM-OM) ultraviolet (UV) data to study galaxy evolution. Our sample is constructed as the intersection of all Abell clusters with z < 0:05 and having archival XMM-OM data in either the UVM2 or UVW1 filters, plus optical and UV photometry from the Sloan Digital Sky Survey and GALEX, respectively. The 11 resulting clusters include 726 galaxies with measured redshifts, 520 of which have redshifts placing them within their parent Abell clusters. We develop procedures for manipulating the XMM-OM images and measuring galaxy photometry from them, and we confirm our results via comparison with published catalogs. Color-magnitude diagrams (CMDs) constructed using the XMM-OM data along with SDSS optical data show promise for evolutionary studies, with good separation between red and blue sequences and real variation in the width of the red sequence that is likely indicative of differences in star formation history. This is particularly true for UVW1 data, as the relative abundance of data collected using this filter and its depth make it an attractive choice. Available tools that use stellar synthesis libraries to fit the UV and optical photometric data may also be used, thereby better describing star formation history within the past billion years and providing estimates of total stellar mass that include contributions from young stars. Finally, color-color diagrams that include XMM-OM UV data appear useful to the photometric identification of both extragalactic and stellar sources.

Red sequence of Abell X-ray underluminous clusters

“…Going into more detail, some recent models suggest that the fainter red-sequence (RS) galaxies have quenched their star formation only recently (and maybe suffered some events of wet mergers prior to that) and then settled in the RS (Smail et al 1998;Tanaka et al 2005;Faber et al 2007;Miller et al 2012). Brighter RS galaxies, instead, are the prototype RS galaxies: they had the bulk of their stellar content already in place at z > 1 and only evolved by major or minor dry mergers (of other RS galaxies) after that.…”