Volume 592, August 2016
The XXL Survey: First results
|Number of page(s)||17|
|Section||Cosmology (including clusters of galaxies)|
|Published online||15 June 2016|
The XXL Survey
1 School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
2 H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK
3 Argelander Institut für Astronomie, Universität Bonn, 53121 Bonn, Germany
4 Service d’Astrophysique AIM, CEA Saclay, 91191 Gif-sur-Yvette, France
5 Université Aix Marseille, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
6 Max-Planck-Institut für Astrophysik, Karl-Schwarzschild Str. 1, 85748 Garching, Germany
7 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
8 Max Planck Institut für Extraterrestrische Physik, Postfach 1312, 85741 Garching bei München, Germany
9 Department of Astronomy, University of Geneva, ch. d’Ecogia 16, 1290 Versoix, Switzerland
10 INAF–IASF-Milano, via E. Bassini 15, 20133 Milano, Italy
11 INAF–Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
12 INFN, Sezione di Bologna, viale Berti Pichat 6\2, 40127 Bologna, Italy
13 Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 1A1, Canada
14 SEDI CEA Saclay, France
15 Astrophysics Research Institute, Liverpool John Moores University, IC2, 146 Brownlow Hill, Liverpool L3 5RF, UK
Received: 3 July 2015
Accepted: 20 October 2015
Context. The XXL Survey is the largest survey carried out by XMM-Newton. Covering an area of 50 deg2, the survey contains ~450 galaxy clusters out to a redshift ~2 and to an X-ray flux limit of ~ 5 × 10-15 erg s-1 cm-2. This paper is part of the first release of XXL results focussed on the bright cluster sample.
Aims. We investigate the scaling relation between weak-lensing mass and X-ray temperature for the brightest clusters in XXL. The scaling relation discussed in this article is used to estimate the mass of all 100 clusters in XXL-100-GC.
Methods. Based on a subsample of 38 objects that lie within the intersection of the northern XXL field and the publicly available CFHTLenS shear catalog, we derive the weak-lensing mass of each system with careful considerations of the systematics. The clusters lie at 0.1 <z< 0.6 and span a temperature range of T ≃ 1−5 keV. We combine our sample with an additional 58 clusters from the literature, increasing the range to T ≃ 1−10 keV. To date, this is the largest sample of clusters with weak-lensing mass measurements that has been used to study the mass-temperature relation.
Results. The mass-temperature relation fit (M ∝ Tb) to the XXL clusters returns a slope b = 1.78+0.37-0.32 and intrinsic scatter σlnM|T≃ 0.53; the scatter is dominated by disturbed clusters. The fit to the combined sample of 96 clusters is in tension with self-similarity, b = 1.67 ± 0.12 and σlnM|T ≃ 0.41.
Conclusions. Overall our results demonstrate the feasibility of ground-based weak-lensing scaling relation studies down to cool systems of ~1 keV temperature and highlight that the current data and samples are a limit to our statistical precision. As such we are unable to determine whether the validity of hydrostatic equilibrium is a function of halo mass. An enlarged sample of cool systems, deeper weak-lensing data, and robust modelling of the selection function will help to explore these issues further.
Key words: gravitational lensing: weak / X-rays: galaxies: clusters / galaxies: groups: general / galaxies: clusters: general
Based on observations obtained with XMM-Newton, an ESA sci- ence mission with instruments and contributions directly funded by ESA Member States and NASA. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme 089.A-0666 and LP191.A-0268.
The Master catalogue is available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (126.96.36.199) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A2
© ESO, 2016
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