Primordial Non-Gaussianity and the NRAO VLA Sky Survey

Abstract

The NRAO VLA Sky Survey (NVSS) is the only dataset that allows an accurate determination of the auto-correlation function (ACF) on angular scales of several degrees for Active Galactic Nuclei (AGNs) at typical redshifts $z\simeq 1$. Surprisingly, the ACF is found to be positive on such large scales while, in the framework of the standard hierarchical clustering scenario with Gaussian primordial perturbations it should be negative for a redshift-independent effective halo mass of order of that found for optically-selected quasars. We show that a small primordial non-Gaussianity can add sufficient power on very large scales to account for the observed NVSS ACF. The best-fit value of the parameter $f_{\mathrm{NL}}$, quantifying the amplitude of primordial non-Gaussianity of local type is $f_{\mathrm{NL}}=62\pm 27$ ($1\sigma$ error bar) and $25<f_{\mathrm{NL}}<117$ ($2\sigma$ confidence level), corresponding to a detection of non-Gaussianity significant at the $\sim 3\sigma$ confidence level. The minimal halo mass of NVSS sources is found to be $M_{\min }=10^{12.47\pm 0.26}{h}^{-1}{M}_{\odot }$ ($1\sigma$) strikingly close to that found for optically selected quasars. We discuss caveats and possible physical and systematic effects that can impact on the results.

6 pages, 5 figures

References in corpus (13)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Improved Cosmological Constraints from New, Old and Combined Supernova Datasets
• The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
• New Perspective on Galaxy Clustering as a Cosmological Probe: General Relativistic Effects
• Effects of Scale-Dependent Non-Gaussianity on Cosmological Structures
• Detection of primordial non-Gaussianity (fNL) in the WMAP 3-year data at above 99.5% confidence
• Optimal limits on f_{NL}^{local} from WMAP 5-year data
• An Estimate of the Primordial Non-Gaussianity Parameter f_NL Using the Needlet Bispectrum from WMAP
• Non-gaussianity of inflationary field perturbations from the field equation
• A Combined EIS-NVSS Survey Of Radio Sources (CENSORS) III: Spectroscopic observations
• Scale-dependent bias from primordial non-Gaussianity in general relativity
• Improved constraints on primordial non-Gaussianity for the Wilkinson Microwave Anisotropy Probe 5-yr data
• The large scale clustering of radio sources

Cited by in corpus (16)

• Constraints on Multi-Field Inflation from the BOSS Galaxy Survey
• The significance of the integrated Sachs-Wolfe effect revisited
• On Classification of Models of Large Local-Type Non-Gaussianity
• The VLT LBG Redshift Survey - III. The clustering and dynamics of Lyman-break galaxies at z ~ 3
• Constraining Primordial Non-Gaussianity with High-Redshift Probes
• Tomography of the Fermi-LAT gamma-ray diffuse extragalactic signal via cross-correlations with galaxy catalogs
• Non-Gaussianity and large-scale structure in a two-field inflationary model
• Using Large Scale Structure to test Multifield Inflation
• Strong scale dependent bispectrum in the Starobinsky model of inflation
• Non-local bias in the halo bispectrum with primordial non-Gaussianity
• Relativistic corrections and non-Gaussianity in radio continuum surveys
• Constraints on Running of Non-Gaussianity from Large Scale Structure Probes
• A measurement of the Integrated Sachs-Wolfe Effect with the Rapid ASKAP Continuum Survey
• Constraints on primordial non-Gaussianity from Galaxy-CMB lensing cross-correlation
• Probing the global 21-cm background by velocity-induced dipole and quadrupole anisotropies
• CMB lensing tomography with clustering estimation of lens redshift distributions