Correlations between triaxial shapes and formation history of dark matter haloes

Erwin T. Lau, Andrew P. Hearin, Daisuke Nagai, Nico Cappelluti

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The shape of dark matter (DM) haloes plays a critical role in constraining cosmology with upcoming large-scale structure surveys. In this paper, we study the correlations between the triaxial shapes and formation histories in DM haloes in the MultiDark Planck 2 N-body cosmological simulation. We find that halo ellipticity is strongly correlated with halo properties that serve as proxies of halo formation history, such as halo concentration and the normalized peak-centroid offset. These correlations are nearly independent of the halo density peak height. We present a simple model for the correlation between halo ellipticity and concentration using conditional abundance matching, and provide fitting formulae for the multidimensional distributions of triaxial halo shape as a function of halo peak height. We apply our halo shape model to gauge the effects of halo ellipticity and orientation bias on the excess surface mass density profiles in cluster-sized haloes. Our model should be useful for exploring the impact of triaxial halo shape on cosmological constraints in upcoming weak lensing surveys of galaxy clusters.

Original languageEnglish (US)
Pages (from-to)1029-1037
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume500
Issue number1
DOIs
StatePublished - Jan 1 2021

Keywords

  • cosmology: Theory
  • dark matter
  • galaxies: clusters: general
  • galaxies: groups: general
  • large-scale structure of Universe
  • methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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