The XXL Survey

XVI. The clustering of X-ray selected galaxy clusters at z ~ 0.3^★

¹ Dipartimento di Fisica e Astronomia – Alma Mater Studiorum Università di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy
e-mail: federico.marulli3@unibo.it
² INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, via Piero Gobetti 93/3, 40129 Bologna, Italy
³ INFN – Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
⁴ Dipartimento di Fisica, Università degli Studi Roma Tre, via della Vasca Navale 84, 00146 Rome, Italy
⁵ Argelander Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
⁶ AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, 91191 Gif-sur-Yvette, France
⁷ National Observatory of Athens, Lofos Nymphon, Thession, Athens 11810, Greece
⁸ Physics Department, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
⁹ Laboratoire Lagrange, UMR 7293, Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, 06304 Nice, France
¹⁰ Aix Marseille Univ., CNRS, CNES, LAM, Marseille, France
¹¹ Department of Astronomy and Space Sciences, Faculty of Science, Istanbul University, 34119 Istanbul, Turkey
¹² Telespazio Vega UK for ESA, European Space Astronomy Centre, Operations Department, 28691 Villanueva de la Cañada, Spain
¹³ H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
¹⁴ Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano, via Bassini 15, 20133 Milan, Italy
¹⁵ Australian Astronomical Observatory, North Ryde, NSW 2113, Australia
¹⁶ The Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia
¹⁷ Service d’Électronique des Détecteurs et d’Informatique, CEA/DSM/IRFU/SEDI, CEA Saclay, 91191 Gif-sur-Yvette, France
¹⁸ Osservatorio Astronomico di Padova, INAF, 35141 Padova, Italy
¹⁹ European Southern Observatory, Alonso de Córdova 3107, Vitacura, 19001 Casilla, Santiago de Chile, Chile
²⁰ Ulugh Beg Astronomical Institute of the Uzbek Academy of Sciences, 33 Astronomicheskaya str., Tashkent, 100052, Uzbekistan

Received: 15 April 2018
Accepted: 21 June 2018

Abstract

Context. Galaxy clusters trace the highest density peaks in the large-scale 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 X-ray selected galaxy clusters from the XXL survey, the largest programme carried out by the XMM-Newton satellite. The measurements are compared to Λ-cold dark matter predictions, and used in combination with self-calibrated mass scaling relations to constrain the effective bias of the sample, b_eff, and the matter density contrast, Ω_M.

Methods. We measured the angle-averaged two-point correlation function of the XXL cluster sample. The analysed catalogue consists of 182 X-ray selected clusters from the XXL second data release, with median redshift ⟨z⟩ = 0.317 and median mass ⟨M₅₀₀⟩≃ 1.3 × 10¹⁴M_⊙. 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 redshift-space 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 two-point correlation function of an X-ray 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.