Halo clustering and g_{NL}-type primordial non-Gaussianity

TL;DR

This paper investigates how primordial non-Gaussianity of the g_{NL} type affects halo clustering, providing a new bias expression validated by simulations to help constrain early universe models.

Contribution

It introduces a simple, theoretically motivated halo bias formula for g_{NL}-type non-Gaussianity, validated by simulations, aiding observational constraints.

Findings

Derived a halo bias expression consistent with N-body simulations.

Identified limitations in constraining g_{NL} from low-bias tracer populations.

Validated two analytic methods for studying halo clustering in non-Gaussian models.

Abstract

A wide range of multifield inflationary models generate non-Gaussian initial conditions in which the initial adiabatic fluctuation is of the form (zeta_G + g_{NL} zeta_G^3). We study halo clustering in these models using two different analytic methods: the peak-background split framework, and brute force calculation in a barrier crossing model, obtaining agreement between the two. We find a simple, theoretically motivated expression for halo bias which agrees with N-body simulations and can be used to constrain g_{NL} from observations. We discuss practical caveats to constraining g_{NL} using only observable properties of a tracer population, and argue that constraints obtained from populations whose observed bias is <~ 2.5 are generally not robust to uncertainties in modeling the halo occupation distribution of the population.