The connection between halo concentrations and assembly histories: a probe of gravity?

Abstract

We use two high resolution N-body simulations, one assuming general relativity and the other the Hu-Sawicki form of $f\left(R\right)$ gravity with $|{\bar{f}}_R|=10^{-6}$, to investigate the concentration--formation time relation of dark matter haloes. We stack haloes in logarithmically spaced mass bins to fit median density profiles and extract median formation times. At fixed mass, haloes in modified gravity are more concentrated than those in GR, especially at low masses and at low redshift, and do not follow the concentration--formation time relation seen in GR. We assess the sensitivity of the relation to how concentration and formation time are defined, as well as to the segregation of the halo population by the amount of gravitational screening. We find a clear difference between halo concentrations and assembly histories displayed in modified gravity and those in GR. Existing models for the mass--concentration--redshift relation that have gained success in cold and warm dark matter models require revision in $f\left(R\right)$ gravity.

12 pages, 10 figures

References in corpus (14)

• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Beyond the Cosmological Standard Model
• Concentration, Spin and Shape of Dark Matter Haloes as a Function of the Cosmological Model: WMAP1, WMAP3 and WMAP5 results
• The redshift dependence of the structure of massive LCDM halos
• A universal model for halo concentrations
• An accurate physical model for halo concentrations
• Non-linear Evolution of f(R) Cosmologies III: Halo Statistics
• HBT+: an improved code for finding subhalos and building merger trees in cosmological simulations
• New observational constraints on $f(R)$ gravity from cosmic chronometers
• Constraining chameleon models with cosmology
• The inner structure of haloes in Cold+Warm dark matter models
• Vector field models of modified gravity and the dark sector
• Testing the quasi-static approximation in $f(R)$ gravity simulations
• No evidence for modifications of gravity from galaxy motions on cosmological scales

Cited by in corpus (2)

• Mass accretion rates of clusters of galaxies: CIRS and HeCS
• Constraining Chameleon screening using galaxy cluster dynamics