The phase-space structure of dark matter haloes

Han Aung, Daisuke Nagai, Eduardo Rozo, Rafael García

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The phase space structure of dark matter haloes can be used to measure the mass of the halo, infer mass accretion rates, and probe the effects of modified gravity. Previous studies showed that the splashback radius can be measured in position space using a sharp drop in the density profile. Using N-body simulations, we model the distribution of the kinematically distinct infalling and orbiting populations of subhaloes and haloes. We show that the two are mixed spatially all the way to redge, which extends past the splashback radius defined by the drop in the spherically averaged density profile. This edge radius can be interpreted as a radius that contains a fixed fraction of the apocentres of dark matter particles. Our results highlight the possibility of measuring the outer boundary of a dark matter halo using its phase space structure and provide a firm theoretical foundation to the satellite galaxy model adopted in the companion paper, where we analysed the phase space distribution of Sloan Digital Sky Survey redMaPPer clusters.

Original languageEnglish (US)
Pages (from-to)1041-1047
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Mar 1 2021


  • cosmology: theory
  • dark matter
  • galaxies: clusters: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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