The bias of dark matter tracers: assessing the accuracy of mapping techniques

TL;DR

This paper compares parametric and non-parametric bias mapping methods for creating mock catalogs of dark matter halos, finding non-parametric approaches highly accurate and suitable for upcoming large-scale structure surveys.

Contribution

It demonstrates that non-parametric bias mapping methods outperform parametric ones in reproducing halo distributions, enabling more precise mock catalog generation for cosmological analyses.

Findings

Non-parametric approach matches N-body simulations in power spectrum beyond k=1 h/Mpc.

Non-parametric approach accurately reproduces bispectrum for BAO-relevant configurations.

Parametric approach remains inaccurate even with complex bias components.

Abstract

We present a comparison between approximated methods for the construction of mock catalogs based on the halo-bias mapping technique. To this end, we use as reference a high resolution $N$-body simulation of 3840$^3$ dark matter particles on a 400$h^{-1}\rm{Mpc}$ cube box from the Multidark suite. In particular, we explore parametric versus non-parametric bias mapping approaches and compare them at reproducing the halo distribution in terms of the two and three point statistics down to $\sim 10^8\,{\rm M}_{\odot}\,h^{-1}$ halo masses. Our findings demonstrate that the parametric approach remains inaccurate even including complex deterministic and stochastic components. On the contrary, the non-parametric one is indistinguishable from the reference $N$-body calculation in the power-spectrum beyond $k=1\,h\,{\rm Mpc}^{-1}$, and in the bispectrum for typical configurations relevant to baryon acoustic oscillation analysis. We conclude, that approaches which extract the full bias information from $N$-body simulations in a non-parametric fashion are ready for the analysis of the new generation of large scale structure surveys.