Constraining Primordial Non-Gaussianity with High-Redshift Probes

TL;DR

This paper constrains primordial non-Gaussianity using large-scale structure data from radio sources and quasars, analyzing auto- and cross-correlation functions with CMB, and accounts for systematic effects to refine $f_{NL}$ estimates.

Contribution

It introduces a method leveraging large-scale bias dependence to constrain $f_{NL}$ from high-redshift probes, incorporating systematic effects for more reliable estimates.

Findings

Constraints on $f_{NL}$ are consistent with previous results.

Derived $f_{NL}$ values are approximately 53 and 58 with uncertainties around 25.

Systematic effects are carefully modeled and included in the analysis.

Abstract

We present an analysis of the constraints on the amplitude of primordial non-Gaussianity of local type described by the dimensionless parameter $f_{\rm NL}$. These constraints are set by the auto-correlation functions (ACFs) of two large scale structure probes, the radio sources from NRAO VLA Sky Survey (NVSS) and the quasar catalogue of Sloan Digital Sky Survey Release Six (SDSS DR6 QSOs), as well as by their cross-correlation functions (CCFs) with the cosmic microwave background (CMB) temperature map (Integrated Sachs-Wolfe effect). Several systematic effects that may affect the observational estimates of the ACFs and of the CCFs are investigated and conservatively accounted for. Our approach exploits the large-scale scale-dependence of the non-Gaussian halo bias. The derived constraints on {$f_{\rm NL}$} coming from the NVSS CCF and from the QSO ACF and CCF are weaker than those previously obtained from the NVSS ACF, but still consistent with them. Finally, we obtain the constraints on $f_{\rm NL}=53\pm25$ ($1\,\sigma$) and $f_{\rm NL}=58\pm24$ ($1\,\sigma$) from NVSS data and SDSS DR6 QSO data, respectively.