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

Piotr Oleskiewicz, Carlton M. Baugh, Aaron D. Ludlow

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
63 Downloads (Pure)


We use two high-resolution N-body simulations, one assuming general relativity (GR) and the other the Hu–Sawicki form of f(R) gravity with |f¯R| = 10−6, to investigate the concentration–formation time relation of dark matter haloes. We assign haloes to logarithmically spaced mass bins, and fit median density profiles and extract median formation times in each bin. At fixed mass, haloes in modified gravity are more concentrated than those in GR, especially at low masses and 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(R) gravity.

Original languageEnglish
Pages (from-to)4658-4668
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - 11 Nov 2019


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