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

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

doi:10.1103/physrevlett.112.221102

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

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

Authors

W.A. Hellwing

A. Barreira

C.S. Frenk

Professor Baojiu Li baojiu.li@durham.ac.uk
Professor

Professor Shaun Cole shaun.cole@durham.ac.uk
Director of the Institute for Computational Cosmology

Abstract

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.

Citation

Hellwing, W., Barreira, A., Frenk, C., Li, B., & Cole, S. (2014). Clear and measurable signature of modified gravity in the galaxy velocity field. Physical Review Letters, 112(22), Article 221102. https://doi.org/10.1103/physrevlett.112.221102

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
DOI	https://doi.org/10.1103/physrevlett.112.221102

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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.