Large-scale non-Gaussian mass function and halo bias: tests on N-body simulations

TL;DR

This paper tests analytical models of non-Gaussian halo abundance and clustering against N-body simulations, finding good agreement with specific corrections, and highlights the robustness of halo bias as a probe of primordial non-Gaussianity.

Contribution

It calibrates and validates analytical formulas for non-Gaussian halo mass function and bias using N-body simulations, with specific correction factors identified.

Findings

Excellent agreement between simulations and predictions with corrections

Corrections involve factors of sqrt{q} and q in collapse threshold and bias

Non-Gaussian halo bias is a robust probe of primordial non-Gaussianity

Abstract

The description of the abundance and clustering of halos for non-Gaussian initial conditions has recently received renewed interest, motivated by the forthcoming large galaxy and cluster surveys, which can potentially yield constraints of order unity on the non-Gaussianity parameter f_{NL}. We present tests on N-body simulations of analytical formulae describing the halo abundance and clustering for non-Gaussian initial conditions. We calibrate the analytic non-Gaussian mass function of Matarrese et al.(2000) and LoVerde et al.(2008) and the analytic description of clustering of halos for non-Gaussian initial conditions on N-body simulations. We find excellent agreement between the simulations and the analytic predictions if we make the corrections delta_c --> delta_c X sqrt{q} and delta_c --> \delta_c X q where q ~ 0.75, in the density threshold for gravitational collapse and in the non-Gaussian fractional correction to the halo bias, respectively. We discuss the implications of this correction on present and forecasted primordial non-Gaussianity constraints. We confirm that the non-Gaussian halo bias offers a robust and highly competitive test of primordial non-Gaussianity.