N-body simulations with generic non-Gaussian initial conditions II: Halo bias

TL;DR

This paper uses large-scale N-body simulations to model and analyze the scale-dependent halo bias caused by non-Gaussian initial conditions, improving implementation methods and validating analytic predictions.

Contribution

It introduces an improved method for implementing generic non-Gaussian initial conditions and validates analytic models for halo bias against simulation results.

Findings

Analytic predictions match simulation results after calibration.

Halo bias remains a powerful probe of primordial non-Gaussianity.

Enhanced implementation reduces large-scale power spectrum distortions.

Abstract

We present N-body simulations for generic non-Gaussian initial conditions with the aim of exploring and modelling the scale-dependent halo bias. This effect is evident at very large scales requiring large simulation boxes. In addition, the previously available prescription to implement generic non-Gaussian initial conditions has been improved to keep under control higher-order terms which were spoiling the power spectrum on large scales. We pay particular attention to the differences between physical, inflation-motivated primordial bispectra and their factorizable templates, and to the operational definition of the non-Gaussian halo bias (which has both a scale-dependent and an approximately scale-independent contributions). We find that analytic predictions for both the non-Gaussian halo mass function and halo bias work well once a calibration factor (which was introduced before) is calibrated on simulations. The halo bias remains therefore an extremely promising tool to probe primordial non-Gaussianity and thus to give insights into the physical mechanism that generated the primordial perturbations. The simulation outputs and tables of the analytic predictions will be made publicly available via the non-Gaussian comparison project web site http://icc.ub.edu/~liciaverde/NGSCP.html