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Dynamical masses in modified gravity

Schmidt, Fabian (2010) Dynamical masses in modified gravity. Physical Review D, 81 (10). Art. No. 103002. ISSN 2470-0010.

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Differences in masses inferred from dynamics, such as velocity dispersions or x rays, and those inferred from lensing are a generic prediction of modified gravity theories. Viable models, however, must include some nonlinear mechanism to restore general relativity (GR) in dense environments, which is necessary to pass Solar System constraints on precisely these deviations. In this paper, we study the dynamics within virialized structures in the context of two modified gravity models, f(R) gravity and Dvali-Gabadadze-Porrati (DGP). The nonlinear mechanisms to restore GR, which f(R) and DGP implement in very different ways, have a strong impact on the dynamics in bound objects; they leave distinctive signatures in the dynamical mass-lensing mass relation as a function of mass and radius. We present measurements from N-body simulations of f(R) and DGP, as well as semianalytical models that match the simulation results to surprising accuracy in both cases. The semianalytical models are useful for making the connection to observations. Our results confirm that the environment and scale dependence of the modified gravity effects have to be taken into account when confronting gravity theories with observations of dynamics in galaxies and clusters.

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Additional Information:© 2010 The American Physical Society. Received 10 March 2010; published 7 May 2010. I would like to thank Wayne Hu, Tristan Smith, Mark Wyman, and Donghai Zhao for discussions and comments on the paper. This work was supported by the Gordon and Betty Moore Foundation at Caltech. The simulations used in this work have been performed on the Joint Fermilab- KICP Supercomputing Cluster, supported by grants from Fermilab, Kavli Institute for Cosmological Physics, and the University of Chicago.
Group:Moore Center for Theoretical Cosmology and Physics
Funding AgencyGrant Number
Gordon and Betty Moore Foundation, CaltechUNSPECIFIED
Fermilab, Kavli Institute for Cosmological PhysicsUNSPECIFIED
University of ChicagoUNSPECIFIED
Issue or Number:10
Classification Code:PACS: 95.30.Sf, 04.50.Kd, 95.36.+x, 98.80.Jk
Record Number:CaltechAUTHORS:20100624-143823509
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:18805
Deposited By: Tony Diaz
Deposited On:09 Jul 2010 21:37
Last Modified:03 Oct 2019 01:48

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