A general framework to test gravity using galaxy clusters I: Modelling the dynamical mass of haloes in f(R) gravity

Mitchell, Myles A; He, Jian-hua; Arnold, Christian; Li, Baojiu

Abstract

We propose a new framework for testing gravity using cluster observations, which aims to provide an unbiased constraint on modified gravity models from Sunyaev Zel’dovich (SZ) and X-ray cluster counts and the cluster gas fraction, among other possible observables. Focusing on a popular f(R) model of gravity, we propose a novel procedure to recalibrate mass scaling relations from ΛCDM to f(R) gravity for SZ and X-ray cluster observables. We find that the complicated modified gravity effects can be simply modelled as a dependence on a combination of the background scalar field and redshift, fR(z)/(1 + z), regardless of the f(R) model parameter. By employing a large suite of N-body simulations, we demonstrate that a theoretically derived tanh  fitting formula is in excellent agreement with the dynamical mass enhancement of dark matter haloes for a large range of background field parameters and redshifts. Our framework is sufficiently flexible to allow for tests of other models and inclusion of further observables, and the one-parameter description of the dynamical mass enhancement can have important implications on the theoretical modelling of observables and on practical tests of gravity.

Citation

Mitchell, M. A., He, J., Arnold, C., & Li, B. (2018). A general framework to test gravity using galaxy clusters I: Modelling the dynamical mass of haloes in f(R) gravity. Monthly Notices of the Royal Astronomical Society, 477(1), 1133-1152. https://doi.org/10.1093/mnras/sty636

• Journal Article Type: Article
• Acceptance Date: Mar 7, 2018
• Online Publication Date: Mar 9, 2018
• Publication Date: Jun 11, 2018
• Deposit Date: Mar 29, 2018
• Publicly Available Date: Apr 3, 2018
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 477
• Issue: 1
• Pages: 1133-1152
• DOI: https://doi.org/10.1093/mnras/sty636
• Related Public URLs: https://arxiv.org/abs/1802.02165