Constraints on Primordial Non-Gaussianity from Large Scale Structure Probes

TL;DR

This study analyzes large-scale structure data to constrain primordial non-Gaussianity parameters, providing limits on different non-Gaussianity templates and the cubic correction to halo bias, enhancing understanding of early universe conditions.

Contribution

It presents the first comprehensive constraints on primordial non-Gaussianity using multiple large-scale structure probes and their cross-correlations with CMB data.

Findings

Constraints on local $f_{NL}$: 48 ± 20

Constraints on equilateral $f_{NL}$: 50 ± 265

Constraints on enfolded $f_{NL}$: 183 ± 95

Abstract

In this paper we measure the angular power spectra $C_\ell$ of three high-redshift large-scale structure probes: the radio sources from the NRAO VLA Sky Survey (NVSS), the quasar catalogue of Sloan Digital Sky Survey Release Six (SDSS DR6 QSOs) and the MegaZ-LRG (DR7), the final SDSS II Luminous Red Galaxy (LRG) photometric redshift survey. We perform a global analysis of the constraints on the amplitude of primordial non-Gaussianity from these angular power spectra, as well as from their cross-correlation power spectra with the cosmic microwave background (CMB) temperature map. In particular, we include non-Gaussianity of the type arising from single-field slow roll, multifields, curvaton (local type), and those which effects on the halo clustering can be described by the equilateral template (related to higher-order derivative type non-Gaussianity) and by the enfolded template (related to modified initial state or higher-derivative interactions). When combining all data sets, we obtain limits of $f_{\rm NL}=48\pm20$, $f_{\rm NL}=50\pm265$ and $f_{\rm NL}=183\pm95$ at 68% confidence level for local, equilateral and enfolded templates, respectively. Furthermore, we explore the constraint on the cubic correction $g_{\rm NL}\phi^3$ on the bias of dark matter haloes and obtain a limit of $-1.2\times10^5<g_{\rm NL}<11.3\times10^5$ at 95% confidence level.