AN ESTIMATE OF THE PRIMORDIAL NON-GAUSSIANITY PARAMETER f {sub NL} USING THE NEEDLET BISPECTRUM FROM WMAP
- Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway)
- Dipartimento di Matematica, Universita di Roma 'Tor Vergata', Via della Ricerca Scientifica 1, I-00133 Roma (Italy)
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberfoce Road, Cambridge CB3 0WA (United Kingdom)
- Dipartimento di Fisica, G. Galilei, Universita di Padova and INFN, Sezione di Padova, via Marzolo 8, I-35131 Padova (Italy)
We use the full bispectrum of spherical needlets applied to the WMAP data of the cosmic microwave background as an estimator for the primordial non-Gaussianity parameter f {sub NL}. We use needlet scales up to l{sub max} = 1000 and the KQ75 galactic cut and find f {sub NL} = 84 {+-} 40 corrected for point-source bias. We also introduce a set of consistency tests to validate our results against the possible influence of foreground residuals or systematic errors. In particular, fluctuations in the value of f {sub NL} obtained from different frequency channels, different masks, and different multipoles are tested against simulated maps. All variations in f {sub NL} estimates are found statistically consistent with simulations.
- OSTI ID:
- 21313692
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 701; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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