Non-Gaussianity and Excursion Set Theory: Halo Bias

TL;DR

This paper investigates how primordial non-Gaussianity affects halo bias in large-scale structure, using excursion set theory to analyze both spherical and non-spherical halos and identifying key approximations and corrections.

Contribution

It provides a detailed analysis of halo bias under non-Gaussian initial conditions, including non-spherical collapse, with explicit identification of approximations and corrections.

Findings

Bias scales as k^{-2} for local non-Gaussianity on large scales

Explicit identification of approximations in bias calculations

Analysis of non-spherical halo collapse with scale-dependent thresholds

Abstract

We study the impact of primordial non-Gaussianity generated during inflation on the bias of halos using excursion set theory. We recapture the familiar result that the bias scales as $k^{-2}$ on large scales for local type non-Gaussianity but explicitly identify the approximations that go into this conclusion and the corrections to it. We solve the more complicated problem of non-spherical halos, for which the collapse threshold is scale dependent.