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Testing gravity theories via transverse Doppler and gravitational redshifts in galaxy clusters

Zhao, H.; Peacock, J.; Li, B.

Testing gravity theories via transverse Doppler and gravitational redshifts in galaxy clusters Thumbnail


H. Zhao

J. Peacock


There is growing interest in testing alternative gravity theories using the subtle gravitational redshifts in clusters of galaxies. However, current models all neglect a transverse Doppler redshift of similar magnitude, and some models are not self-consistent. An equilibrium model would fix the gravitational and transverse Doppler velocity shifts to be about 6σ2/c and 3σ2/2c in order to fit the observed velocity dispersion σ self-consistently. This result comes from the virial theorem for a spherical isotropic cluster, and is insensitive to the theory of gravity. A gravitational redshift signal also does not directly distinguish between the Einsteinian and f(R) gravity theories, because each theory requires a different dark halo mass function to keep the clusters in equilibrium. When this constraint is imposed, the gravitational redshift has no sensitivity to theory. Indeed, our N-body simulations show that the halo mass function differs in f(R), and that the transverse Doppler effect is stronger than analytically predicted due to nonequilibrium.

Journal Article Type Article
Publication Date Aug 1, 2013
Deposit Date Mar 27, 2013
Publicly Available Date May 8, 2014
Journal Physical Review D
Print ISSN 1550-7998
Electronic ISSN 1550-2368
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 88
Issue 4
Article Number 043013
Public URL


Published Journal Article (193 Kb)

Copyright Statement
Reprinted with permission from the American Physical Society: Zhao, H. and Peacock, J. and Li, B., Physical review D, 88 (4). p. 043013, 2013. © 2013 by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.

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