The XXL Survey: IV. Mass-temperature relation of the bright cluster sample

Maggie Lieu, Paul A. Giles, Felicia Ziparo, Ben J. Maughan, Jessica Démoclès, Florian Pacaud, Marguerite Pierre, Christophe Adami, Yannick M. Bahé, Nicolas Clerc, Lucio Chiappetti, Dominique Eckert, Stefano Ettori, Sébastien Lavoie, Jean-Paul Le Fevre, Ian G. McCarthy, Martin Kilbinger, Trevor J. Ponman, Tatyana Sadibekova, Jon P. Willis

Research output: Contribution to journalArticle (Academic Journal)peer-review

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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 (MTb) 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.

Original languageEnglish
Article numberA4
Number of pages17
JournalAstronomy and Astrophysics
Early online date15 Jun 2016
Publication statusPublished - Aug 2016


  • gravitational lensing: weak
  • X-rays: galaxies: clusters
  • galaxies: groups: general
  • galaxies: clusters: general


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