Signature of primordial non-Gaussianity of phi^3-type in the mass function and bias of dark matter haloes

TL;DR

This paper investigates the impact of a cubic non-Gaussianity term on dark matter halo properties using simulations and compares results with theoretical models, providing new observational constraints on the cubic parameter gnl.

Contribution

It presents the first observational limits on the cubic non-Gaussianity parameter gnl using large-scale structure data, and compares simulation results with theoretical predictions.

Findings

Deviation from Gaussian mass function aligns with theory

Scale-dependent bias correction is lower than expected

New constraints on gnl parameter from LSS data

Abstract

We explore the effect of a cubic correction gnl*phi^3 on the mass function and bias of dark matter haloes extracted from a series of large N-body simulations and compare it to theoretical predictions. Such cubic terms can be motivated in scenarios like the curvaton model, in which a large cubic correction can be produced while simultaneously keeping the quadratic fnl*phi^2 correction small. The deviation from the Gaussian halo mass function is in reasonable agreement with the theoretical predictions. The scale-dependent bias correction Delta b_kappa(k,gnl) measured from the auto- and cross-power spectrum of haloes, is similar to the correction in fnl models, but the amplitude is lower than theoretical expectations. Using the compilation of LSS data in Slosar et al. (2008), we obtain for the first time a limit on gnl of -3.5*10^5 < gnl < +8.2*10^5 (at 95% CL). This limit will improve with the future LSS data by 1-2 orders of magnitude, which should test many of the scenarios of this type.