The XXL Survey. XXV. Cosmological analysis of the C1 cluster number counts
Abstract
Context. We present an estimation of cosmological parameters with clusters of galaxies.
Aims: We constrain the Ω_{m}, σ_{8}, and w parameters from a standalone sample of Xray clusters detected in the 50 deg^{2} XMMXXL survey with a welldefined selection function.
Methods: We analyse the redshift distribution of a sample comprising 178 high signaltonoise ratio clusters out to a redshift of unity. The cluster sample scaling relations are determined in a selfconsistent manner.
Results: In a lambda cold dark matter (ΛCDM) model, the cosmology favoured by the XXL clusters compares well with results derived from the Planck SunyaevZel'dovich clusters for a totally different sample (mass/redshift range, selection biases, and scaling relations). However, with this preliminary sample and current mass calibration uncertainty, we find no inconsistency with the Planck CMB cosmology. If we relax the w parameter, the Planck CMB uncertainties increase by a factor of 10 and become comparable with those from XXL clusters. Combining the two probes allows us to put constraints on Ω_{m} = 0.316 ± 0.060, σ_{8} = 0.814 ± 0.054, and w = 1.02 ± 0.20.
Conclusions: This first selfconsistent cosmological analysis of a sample of serendipitous XMM clusters already provides interesting insights into the constraining power of the XXL survey. Subsequent analysis will use a larger sample extending to lower confidence detections and include additional observable information, potentially improving posterior uncertainties by roughly a factor of 3.
Based on observations obtained with XMMNewton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 November 2018
 DOI:
 10.1051/00046361/201834022
 arXiv:
 arXiv:1810.01624
 Bibcode:
 2018A&A...620A..10P
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 surveys;
 Xrays: galaxies: clusters;
 galaxies: clusters: intracluster medium;
 largescale structure of Universe;
 cosmological parameters;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 11 pages, 5 figures, 5 tables, accepted as a letter by Astronomy &