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

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

Abstract

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.

Citation

Zhao, H., Peacock, J., & Li, B. (2013). Testing gravity theories via transverse Doppler and gravitational redshifts in galaxy clusters. Physical Review D, 88(4), Article 043013. https://doi.org/10.1103/physrevd.88.043013

• Journal Article Type: Article
• Publication Date: Aug 1, 2013
• Deposit Date: Mar 27, 2013
• Publicly Available Date: May 8, 2014
• Journal: Physical Review D - Particles, Fields, Gravitation, and Cosmology
• Print ISSN: 1550-7998
• Electronic ISSN: 1550-2368
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 88
• Issue: 4
• Article Number: 043013
• DOI: https://doi.org/10.1103/physrevd.88.043013
• Public URL: https://durham-repository.worktribe.com/output/1490022