Structure formation by the fifth force: segregation of baryons and dark matter

Li, B.; Zhao, H.

Abstract

In this paper we present the results of N-body simulations with a scalar field coupled differently to cold dark matter (CDM) and baryons. The scalar field potential and coupling function are chosen such that the scalar field acquires a heavy mass in regions with high CDM density and thus behaves like a chameleon. We focus on how the existence of the scalar field affects the formation of nonlinear large-scale structures, and how the different couplings of the scalar field to baryons and CDM particles lead to different distributions and evolutions for these two matter species, both on large scales and inside virialized halos. As expected, the baryon-CDM segregation increases in regions where the fifth force is strong, and little segregation in dense regions. We also introduce an approximation method to identify the virialized halos in coupled scalar field models which takes into account the scalar field coupling and which is easy to implement numerically. It is found that the chameleon nature of the scalar field makes the internal density profiles of halos dependent on the environment in a very nontrivial way.

Citation

Li, B., & Zhao, H. (2010). Structure formation by the fifth force: segregation of baryons and dark matter. Physical Review D, 81(10), Article 104047. https://doi.org/10.1103/physrevd.81.104047

• Journal Article Type: Article
• Publication Date: May 1, 2010
• Deposit Date: Jan 20, 2012
• Publicly Available Date: Jul 16, 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: 81
• Issue: 10
• Article Number: 104047
• DOI: https://doi.org/10.1103/physrevd.81.104047
• Public URL: https://durham-repository.worktribe.com/output/1522006