Using the XMM Optical Monitor to Study Cluster Galaxy Evolution

TL;DR

This study demonstrates how XMM-Newton Optical Monitor UV data, combined with optical surveys, can be effectively used to analyze galaxy evolution within galaxy clusters, revealing star formation histories and aiding source identification.

Contribution

The paper develops procedures for extracting galaxy photometry from XMM-OM images and shows their effectiveness in studying galaxy evolution using combined UV and optical data.

Findings

Color-magnitude diagrams effectively distinguish red and blue galaxy sequences.

UVW1 filter data provides deep, abundant information for evolutionary studies.

Color-color diagrams including UV data assist in source classification.

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 eleven 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 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 Gyr 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.