A redefinition of the halo boundary leads to a simple yet accurate halo model of large-scale structure

Rafael García, Eduardo Rozo, Matthew R. Becker, Surhud More

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


We present a model for the halo-mass correlation function that explicitly incorporates halo exclusion and allows for a redefinition of the halo boundary in a flexible way. We assume that haloes trace mass in a way that can be described using a single scale-independent bias parameter. However, our model exhibits scale-dependent biasing due to the impact of halo-exclusion, the use of a 'soft' (i.e. not infinitely sharp) halo boundary, and differences in the one halo term contributions to ζhm and ζmm. These features naturally lead us to a redefinition of the halo boundary that lies at the 'by eye' transition radius from the one-halo to the two-halo term in the halo-mass correlation function. When adopting our proposed definition, our model succeeds in describing the halo-mass correlation function with residuals over the radial range 0.1 h-1 Mpc < r < 80 h-1 Mpc, and for halo masses in the range 1013 h-1 M < M < 1015 h-1 M. Our proposed halo boundary is related to the splashback radius by a roughly constant multiplicative factor. Taking the 87 percentile as reference we find rt/Rsp ≈ 1.3. Surprisingly, our proposed definition results in halo abundances that are well described by the Press-Schechter mass function with δsc = 1.449 ± 0.004. The clustering bias parameter is offset from the standard background-split prediction by This level of agreement is comparable to that achieved with more standard halo definitions.

Original languageEnglish (US)
Pages (from-to)1195-1205
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Jul 1 2021


  • cosmology: theory
  • dark matter
  • large-scale structure of Universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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