The XMM Cluster Survey: testing chameleon gravity using the profiles of clusters

Wilcox, Harry, Bacon, David, Nichol, Robert C, Rooney, Philip J, Terukina, Ayumu, Romer, A Kathy, Koyama, Kazuya, Zhao, Gong-Bo, Hood, Ross, Mann, Robert G, Hilton, Matt, Manolopoulou, Maria, Sahlén, Martin, Collins, Chris A, Liddle, Andrew R, Mayers, Julian A, Mehrtens, Nicola, Miller, Christopher J, Stott, John P and Viana, Pedro T P (2015) The XMM Cluster Survey: testing chameleon gravity using the profiles of clusters. Monthly Notices of the Royal Astronomical Society, 452 (1). pp. 1171-1183. ISSN 0035-8711

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The chameleon gravity model postulates the existence of a scalar field that couples with matter to mediate a fifth force. If it exists, this fifth force would influence the hot X-ray emitting gas filling the potential wells of galaxy clusters. However, it would not influence the clusters weak lensing signal. Therefore, by comparing X-ray and weak lensing profiles, one can place upper limits on the strength of a fifth force. This technique has been attempted before using a single, nearby cluster (Coma, z = 0.02). Here we apply the technique to the stacked profiles of 58 clusters at higher redshifts (0.1 < z < 1.2), including 12 new to the literature, using X-ray data from the XMM Cluster Survey and weak lensing data from the Canada-France-Hawaii-Telescope Lensing Survey. Using a multiparameter Markov chain Monte Carlo analysis, we constrain the two chameleon gravity parameters (beta and phi∞). Our fits are consistent with general relativity, not requiring a fifth force. In the special case of f(R) gravity (where beta = &surd;{1/6}), we set an upper limit on the background field amplitude today of |fR0| < 6 × 10-5 (95 per cent CL). This is one of the strongest constraints to date on |fR0| on cosmological scales. We hope to improve this constraint in future by extending the study to hundreds of clusters using data from the Dark Energy Survey.

Item Type: Article
Keywords: gravitation, gravitational lensing: weak, X-rays: galaxies: clusters
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Richard Chambers
Date Deposited: 27 Jun 2016 13:34
Last Modified: 15 Mar 2017 05:08

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Project NameSussex Project NumberFunderFunder Ref
Astrophysics and Cosmology - Sussex Consolidated GrantG1291STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/L000652/1
2012 Doctoral Training Grant - Quota Studentships (STFC)G0939STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/K502364/1