paper

A Redefinition of the Halo Boundary Leads to a Simple yet Accurate Halo Model of Large Scale Structure

arXiv:2006.12751 · doi:10.1093/mnras/stab1317

Abstract

We present a model for the halo--mass correlation function that explicitly incorporates halo exclusion. We assume that halos 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 and . 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 , and for halo masses in the range . Our proposed halo boundary is related to the splashback radius by a roughly constant multiplicative factor. Taking the 87-percentile as reference we find . Surprisingly, our proposed definition results in halo abundances that are well described by the Press-Schechter mass function with . 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.

12 pages, 5 figures

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