PRIMORDIAL NON-GAUSSIANITY AND THE NRAO VLA SKY SURVEY

Journal Article · Thu Jul 01 04:00:00 EDT 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/717/1/L17· OSTI ID:21451061

Junqing, Xia; Baccigalupi, Carlo; De Zotti, Gianfranco ^[1]; Viel, Matteo ^[2]; Matarrese, Sabino ^[3]; Verde, Licia ^[4]

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1. Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, I-34136 Trieste (Italy)
2. INAF-Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, I-34131 Trieste (Italy)
3. Dipartimento di Fisica 'G. Galilei', Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy)
4. ICREA (Institucio Catalana de Recerca i Estudis Avancats) and Instituto de Ciencias del Cosmos, Universidad de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)

The NRAO VLA Sky Survey (NVSS) is the only data set that allows an accurate determination of the auto-correlation function (ACF) on angular scales of several degrees for active galactic nuclei at z {approx_equal} 1. Surprisingly, the ACF is found to be positive on 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 (NG) can add sufficient power on very large scales to account for the observed NVSS ACF. The best-fit value of the parameter f{sub NL}, quantifying the amplitude of primordial NG of local type, is f{sub NL} = 62 {+-} 27 (1{sigma} error bar) and 25 < f{sub NL} < 117 (2{sigma} confidence level), corresponding to a detection of NG significant at the {approx}3{sigma} confidence level. The minimal halo mass of NVSS sources is found to be M{sub min} = 10{sup 12.47{+-}0.26} h {sup -1} M{sub sun} (1{sigma}) strikingly close to that of optically selected quasars. We discuss caveats and possible physical and systematic effects that can have an impact on the results.

• OSTI ID: 21451061
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 717; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMIC RADIO SOURCES
COSMOLOGY
GALAXIES
GALAXY CLUSTERS
GALAXY NUCLEI
MASS
PERTURBATION THEORY
QUASARS
RED SHIFT
UNIVERSE