Baryon Content of Massive Galaxy Clusters (0.57 < z < 1.33)
Abstract
We study the stellar, Brightest Cluster Galaxy (BCG) and intracluster medium (ICM) masses of 14 South Pole Telescope (SPT) selected galaxy clusters with median redshift and median mass . We estimate stellar masses for each cluster and BCG using six photometric bands spanning the range from the ultraviolet to the near-infrared observed with the VLT, HST and Spitzer. The ICM masses are derived from Chandra and XMM-Newton X-ray observations, and the virial masses are derived from the SPT Sunyaev-Zel'dovich Effect signature. At the BCG mass constitutes % of the halo mass for a cluster, and this fraction falls as . The cluster stellar mass function has a characteristic mass , and the number of galaxies per unit mass in clusters is larger than in the field by a factor . Both results are consistent with measurements on group scales and at lower redshift. We combine our SPT sample with previously published samples at low redshift that we correct to a common initial mass function and for systematic differences in virial masses. We then explore mass and redshift trends in the stellar fraction (fstar), the ICM fraction (fICM), the cold baryon fraction (fc) and the baryon fraction (fb). At a pivot mass of and redshift , the characteristic values are fstar=%, fICM=%, fc=% and fb=%. These fractions all vary with cluster mass at high significance, indicating that higher mass clusters have lower fstar and fc and higher fICM and fb. When accounting for a 15% systematic virial mass uncertainty, there is no statistically significant redshift trend at fixed mass in these baryon fractions. (abridged)
Keywords
Cite
@article{arxiv.1412.7823,
title = {Baryon Content of Massive Galaxy Clusters (0.57 < z < 1.33)},
author = {I. Chiu and J. Mohr and M. Mcdonald and S. Bocquet and M. L. Ashby and M. Bayliss and B. A. Benson and L. E. Bleem and M. Brodwin and S. Desai and J. P. Dietrich and W. R. Forman and C. Gangkofner and A. H. Gonzalez and C. Hennig and J. Liu and C. L. Reichardt and A. Saro and B. Stalder and S. A. Stanford and J. Song and T. Schrabback and R. Suhada and V. Strazzullo and A. Zenteno},
journal= {arXiv preprint arXiv:1412.7823},
year = {2015}
}
Comments
Accepted for publication in MNRAS