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The bispectrum of f(R) cosmologies

Gil-Marín, Héctor and Schmidt, Fabian and Hu, Wayne and Jimenez, Raul and Verde, Licia (2011) The bispectrum of f(R) cosmologies. Journal of Cosmology and Astroparticle Physics, 2011 (11). Art. No. 019. ISSN 1475-7516.

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In this paper we analyze a suite of cosmological simulations of modied gravitational action f(R) models, where cosmic acceleration is induced by a scalar eld that acts as a fifth force on all forms of matter. In particular, we focus on the bispectrum of the dark matter density eld on mildly non-linear scales. For models with the same initial power spectrum, the dark matter bispectrum shows signicant differences for cases where the final dark matter power spectrum also diers. Given the different dependence on bias of the galaxy power spectrum and bispectrum, bispectrum measurements can close the loophole of galaxy bias hiding differences in the power spectrum. Alternatively, changes in the initial power spectrum can also hide differences. By constructing CDM models with very similar final non-linear power spectra, we show that the differences in the bispectrum are reduced (≾ 4%) and are comparable with differences in the imperfectly matched power spectra. These results indicate that the bispectrum depends mainly on the power spectrum and less sensitively on the gravitational signatures of the f(R) model. This weak dependence of the matter bispectrum on gravity makes it useful for breaking degeneracies associated with galaxy bias, even for models beyond general relativity.

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Additional Information:© 2011 IOP Publishing Ltd and SISSA. Received 9 September 2011, accepted for publication 18 October 2011. Published 10 November 2011. We thank Christian Wagner for useful discussions and help with N-body simulations. HGM is supported by a CSIC JAE grant, and thanks the Kavli Institute for Cosmological Physics (KICP) at University of Chicago for hospitality. Part of this work stemmed from discussions at the Centro de Ciencias de Benasque Pedro Pascual. WH is supported by the KICP under NSF contract PHY-0114422, DOE contract DE-FG02-90ER-40560 and the Packard Foundation. LV and RJ are supported by MICINN grant AYA2008-03531. LV acknowledges support from grant FP7 ERC- IDEAS Phys.LSS 240117. FS is supported by the Gordon and Betty Moore Foundation at Caltech.
Group:Moore Center for Theoretical Cosmology and Physics
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-90ER-40560
Packard FoundationUNSPECIFIED
MICINN grantAYA2008-03531
FP7 ERC-IDEAS Phys.LSS240117
Gordon and Betty Moore Foundation,UNSPECIFIED
Subject Keywords:modied gravity, power spectrum, cosmological simulations
Issue or Number:11
Classification Code:PACS: 98.80.Cq; 95.35.+d; 95.30.Sf; 04.20.-q
Record Number:CaltechAUTHORS:20120203-133112782
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Official Citation:The bispectrum of f(R) cosmologies Héctor Gil-Marín et al JCAP11(2011)019
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:29129
Deposited By: Ruth Sustaita
Deposited On:03 Feb 2012 21:59
Last Modified:03 Oct 2019 03:38

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