Comparing Dark Energy Survey and HST-CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter

TL;DR

This study compares stellar mass measurements from DES and CLASH for galaxy cluster RXC J2248.7-4431, demonstrating DES's capability to estimate stellar masses accurately and exploring the relation between stellar and dark matter.

Contribution

It introduces a method to calibrate galaxy properties in DES using space-based CLASH data, enabling large-scale stellar mass fraction analysis in galaxy clusters.

Findings

DES estimates match CLASH within 25% when redshift is fixed.

Stellar-to-total mass fraction within r_200c is approximately 0.0068.

Space-based imaging can calibrate wide-field survey data for galaxy property analysis.

Abstract

We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25% of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensing studies with DES and CLASH. An analysis of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f*=(6.8+-1.7)x10^-3 within a radius of r_200c~2 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both data sets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. The technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the ~100 000 clusters that will be observed within this survey and yield important information about galaxy evolution.