The XXL Survey. XVI. The clustering of Xray selected galaxy clusters at z 0.3
Abstract
Context. Galaxy clusters trace the highest density peaks in the largescale structure of the Universe. Their clustering provides a powerful probe that can be exploited in combination with cluster mass measurements to strengthen the cosmological constraints provided by cluster number counts.
Aims: We investigate the spatial properties of a homogeneous sample of Xray selected galaxy clusters from the XXL survey, the largest programme carried out by the XMMNewton satellite. The measurements are compared to Λcold dark matter predictions, and used in combination with selfcalibrated mass scaling relations to constrain the effective bias of the sample, b_{eff}, and the matter density contrast, Ω_{M}.
Methods: We measured the angleaveraged twopoint correlation function of the XXL cluster sample. The analysed catalogue consists of 182 Xray selected clusters from the XXL second data release, with median redshift ⟨z⟩ = 0.317 and median mass ⟨M_{500}⟩≃ 1.3 × 10^{14}M_{⊙}. A Markov chain Monte Carlo analysis is performed to extract cosmological constraints using a likelihood function constructed to be independent of the cluster selection function.
Results: Modelling the redshiftspace clustering in the scale range 10 < r [h^{1} Mpc] < 40, we obtain Ω_{M} = 0.27_{0.04}^{+0.06} and b_{eff} = 2.73_{0.20}^{+0.18}. This is the first time the twopoint correlation function of an Xray selected cluster catalogue at such relatively high redshifts and low masses has been measured. The XXL cluster clustering appears fully consistent with standard cosmological predictions. The analysis presented in this work demonstrates the feasibility of a cosmological exploitation of the XXL cluster clustering, paving the way for a combined analysis of XXL cluster number counts and clustering.
Based on observations obtained with XMMNewton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. Based on observations made with ESO Telescopes at the La Silla and Paranal Observatories under programmes ID 191.A0268 and 60.A9302.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 November 2018
 DOI:
 10.1051/00046361/201833238
 arXiv:
 arXiv:1807.04760
 Bibcode:
 2018A&A...620A...1M
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 Xrays: galaxies: clusters;
 cosmology: observations;
 largescale structure of Universe;
 cosmological parameters;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 10 pages, 10 figures. Accepted for publication in Astronomy &