Reconstructing the distribution of haloes and mock galaxies below the resolution limit in cosmological simulations

TL;DR

This paper introduces a stochastic sampling method to populate dark matter simulations with low-mass haloes, enabling accurate mock galaxy catalogues and efficient data representation.

Contribution

The method allows reconstructing sub-resolution haloes in simulations using a stochastic approach based on the density field and conditional halo mass functions.

Findings

Accurately reproduces galaxy two-point statistics in mocks

Efficiently communicates full simulation information with fewer haloes

Validates the method's precision in various test scenarios

Abstract

We present a method for populating dark matter simulations with haloes of mass below the resolution limit. It is based on stochastically sampling a field derived from the density field of the halo catalogue, using constraints from the conditional halo mass function n(m|{\delta}). We test the accuracy of the method and show its application in the context of building mock galaxy samples. We find that this technique allows precise reproduction of the two-point statistics of galaxies in mock samples constructed with this method. Our results demonstrate that the full information content of a simulation can be communicated efficiently using only a catalogue of the more massive haloes.