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The XMM cluster survey: Testing chameleon gravity using the profiles of clusters

Wilcox, H and Bacon, D and Nichol, RC and Koyama, K and Zhao, G-B and Rooney, PJ and Kathy Romer, A and Mayers, JA and Terukina, A and Hood, R and Mann, RG and Manolopoulou, M and Liddle, AR and Hilton, M and Sahlén, M and Collins, CA and Mehrtens, N and Miller, CJ and Stott, JP and Viana, PTP (2015) The XMM cluster survey: Testing chameleon gravity using the profiles of clusters. Monthly Notices of the Royal Astronomical Society, 452 (2). 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 (β and ϕ∞). Our fits are consistent with general relativity, not requiring a fifth force. In the special case of f(R) gravity (where β = √1/6), we set an upper limit on the background field amplitude today of |f<inf>R0</inf>| < 6 × 10-5 (95 per cent CL). This is one of the strongest constraints to date on |f<inf>R0</inf>| 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
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 C.A. Collins et al. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: 0201 Astronomical And Space Sciences
Subjects: Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Publisher: Oxford Universitty Press
Date Deposited: 09 Sep 2015 10:44
Last Modified: 07 Sep 2017 06:21
DOI or Identification number: 10.1093/mnras/stv1366
URI: http://researchonline.ljmu.ac.uk/id/eprint/1976

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