Constraining primordial non-Gaussianity with high-redshift probes

Abstract

We present an analysis of the constraints on the amplitude ofprimordial non-Gaussianity of local type described by thedimensionless parameter fNL. These constraints are set bythe auto-correlation functions (ACFs) of two large scale structureprobes, the radio sources from NRAO VLA Sky Survey (NVSS) and theQSO catalogue of Sloan Digital Sky Survey Release Six (SDSS DR6QSOs), as well as by their cross-correlation functions (CCFs) withthe cosmic microwave background (CMB) temperature map (IntegratedSachs-Wolfe effect). Several systematic effects that may affect theobservational estimates of the ACFs and of the CCFs areinvestigated and conservatively accounted for.Our approach exploits the large-scale scale-dependence of thenon-Gaussian halo bias. The derived constraints on {fNL}coming from the NVSS CCF and from the QSO ACF and CCF are weakerthan those previously obtained from the NVSS ACF, but stillconsistent with them. Finally, we obtain the constraints on fNL = 53±25 (1 σ) and fNL = 58±24 (1 σ)from NVSS data and SDSS DR6 QSO data, respectively.