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

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

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
• Public URL: https://durham-repository.worktribe.com/output/1442615