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Clear and measurable signature of modified gravity in the galaxy velocity field

Hellwing, W.A.; Barreira, A.; Frenk, C.S.; Li, B.; Cole, S.

Clear and measurable signature of modified gravity in the galaxy velocity field Thumbnail


W.A. Hellwing

A. Barreira

C.S. Frenk


The velocity field of dark matter and galaxies reflects the continued action of gravity throughout cosmic history. We show that the low-order moments of the pairwise velocity distribution, v 12 , are a powerful diagnostic of the laws of gravity on cosmological scales. In particular, the projected line-of-sight galaxy pairwise velocity dispersion, σ 12 (r) , is very sensitive to the presence of modified gravity. Using a set of high-resolution N-body simulations we compute the pairwise velocity distribution and its projected line-of-sight dispersion for a class of modified gravity theories: the chameleon f(R) gravity and Galileon gravity (cubic and quartic). The velocities of dark matter halos with a wide range of masses exhibit deviations from General Relativity at the 5 to 10 σ level. We examine strategies for detecting these deviations in galaxy redshift and peculiar velocity surveys. If detected, this signature would be a smoking gun for modified gravity.

Journal Article Type Article
Publication Date Jun 5, 2014
Deposit Date Jan 13, 2014
Publicly Available Date Nov 14, 2014
Journal Physical Review Letters
Print ISSN 0031-9007
Electronic ISSN 1079-7114
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 112
Issue 22
Article Number 221102
Public URL


Published Journal Article (244 Kb)

Copyright Statement
Reprinted with permission from the American Physical Society: Physical Review Letters 112, 22, 221102 © 2014 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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