Constraints on Running of Non-Gaussianity from Large Scale Structure Probes

TL;DR

This paper constrains the scale dependence of primordial non-Gaussianity using large-scale structure data and forecasts future improvements with Euclid, providing the first competitive limits on the spectral index of non-Gaussianity from such data.

Contribution

It presents the first competitive constraints on the running of non-Gaussianity from large-scale structure clustering data and forecasts future limits with Euclid.

Findings

Constraint on spectral index: n_NG=0.2^{+0.7}_{-1.0} at 1σ

Forecasted standard deviation for Euclid: Δn_NG=1.74

Provides complementary constraints to CMB bispectrum studies

Abstract

In this letter we present constraints on the scale-dependent "local" type primordial non-Gaussianity, which is described by non-Gaussianity's spectral index $n_{\rm NG}$, from the NRAO VLA Sky Survey and the quasar catalog of the Sloan Digital Sky Survey (SDSS) Data Release 6, together with the SDSS Data Release 12 photo-z sample. Here, we use the auto-correlation analyses of these three probes and their cross-correlation analyses with the cosmic microwave background (CMB) temperature map, and obtain the tight constraint on the spectral index: $n_{\rm NG}=0.2 ^{+0.7}_{-1.0}$ ($1\,\sigma$ C.L.), which shows the first competitive constraint on the running of non-Gaussianity from current large-scale structure clustering data. Furthermore, we also perform the forecast calculations and improve the limit of $n_{\rm NG}$ using the future Euclid mission, and obtain the standard deviation at 68\% confidence level: $\Delta n_{\rm NG}=1.74$ when considering the fiducial value $f_{\rm NL}=3$, which provides the complementary constraining power to those from the CMB bispectrum information.