Distant galaxy clusters in the XMM Large Scale Structure survey
Abstract
Distant galaxy clusters provide important tests of the growth of large-scale structure in addition to highlighting the process of galaxy evolution in a consistently defined environment at large look-back time. We present a sample of 22 distant (z > 0.8) galaxy clusters and cluster candidates selected from the 9 deg2 footprint of the overlapping X-ray Multi Mirror (XMM) Large Scale Structure (LSS), CFHTLS-Wide and Spitzer-SWIRE surveys. Clusters are selected as extended X-ray sources with an accompanying overdensity of galaxies displaying optical to mid-infrared photometry consistent with z > 0.8. Nine clusters have confirmed spectroscopic redshifts in the interval 0.8 < z < 1.2, four of which are presented here for the first time. A further 11 candidate clusters have between 8 and 10 band photometric redshifts in the interval 0.8 < z < 2.2, while the remaining two candidates do not have information in sufficient wavebands to generate a reliable photometric redshift. All of the candidate clusters reported in this paper are presented for the first time. Those confirmed and candidate clusters with available near-infrared photometry display evidence for a red sequence galaxy population, determined either individually or via a stacking analysis, whose colour is consistent with the expectation of an old, coeval stellar population observed at the cluster redshift. We further note that the sample displays a large range of red fraction values indicating that the clusters may be at different stages of red sequence assembly. We compare the observed X-ray emission to the flux expected from a suite of model clusters and find that the sample displays an effective mass limit M200 ∼ 1 × 1014 M⊙ with all clusters displaying masses consistent with M200 < 5 × 1014 M⊙. This XMM distant cluster study represents a complete sample of X-ray-selected z > 0.8 clusters. We discuss the importance of this sample to investigate the abundance of high-redshift clusters and to provide a relatively unbiased view of distant cluster galaxy populations.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2013
- DOI:
- 10.1093/mnras/sts540
- arXiv:
- arXiv:1212.4185
- Bibcode:
- 2013MNRAS.430..134W
- Keywords:
-
- galaxies: clusters: general;
- galaxies: high-redshift;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Accepted by MNRAS, 25 pages, 15 figures