Optical and Sunyaev-Zel'dovich observations of a new sample of distant rich galaxy clusters in the ROSAT All Sky
Abstract
Finding a sample of the most massive clusters with redshifts z > 0.6 can provide an interesting consistency check of the Λ cold dark matter (ΛCDM) model. Here, we present results from our search for clusters with 0.6 ≲ z ≲ 1.0 where the initial candidates were selected by cross-correlating the ROSAT All Sky Survey (RASS) faint and bright source catalogues with red galaxies from the Sloan Digital Sky Survey DR8. Our survey thus covers ≈ 10 000 deg2, much larger than previous studies of this kind. Deeper follow-up observations in three bands using the William Herschel Telescope and the Large Binocular Telescope were performed to confirm the candidates, resulting in a sample of 44 clusters for which we present richnesses and red sequence redshifts, as well as spectroscopic redshifts for a subset. At least two of the clusters in our sample are comparable in richness to RCS2-J232727.7-020437, one of the richest systems discovered to date. We also obtained new observations with the Combined Array for Research in Millimeter Astronomy for a subsample of 21 clusters. For 11 of those we detect the Sunyaev-Zel'dovich effect signature. The Sunyaev-Zel'dovich signal allows us to estimate M200 and check for tension with the cosmological standard model. We find no tension between our cluster masses and the ΛCDM model.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2015
- DOI:
- 10.1093/mnras/stv783
- arXiv:
- arXiv:1412.3304
- Bibcode:
- 2015MNRAS.450.4248B
- Keywords:
-
- cosmology: observations;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 29 pages, 13 figures, to be published in MNRAS 450, 4248-4276 (2015)