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Title: Constraining the WMAP9 bispectrum and trispectrum with needlets

We develop a needlet approach to estimate the amplitude of general (including non-separable) bispectra and trispectra in the cosmic microwave background, and apply this to the WMAP 9-year data. We obtain estimates for the 'orthogonal' bispectrum mode, yielding results which are consistent with the WMAP 7-year data. We do not observe the frequency-dependence suggested by the WMAP team's analysis of the 9-year data. We present 1-σ constraints on the 'local' trispectrum shape g{sub NL}/10{sup 5} = −4.1 ± 2.3, the 'c1' equilateral model g{sup c1}{sub NL}/10{sup 6} = −0.8 ± 2.9, and the constant model g{sup const}{sub NL}/10{sup 6} = −0.2 ± 1.8, together with a 95% confidence-level upper bound on the multifield local parameter τ{sub NL} < 22000. We estimate the bias on these parameters produced by point sources. The techniques developed in this paper should prove useful for other datasets such as Planck.
Authors:
; ;  [1]
  1. Astronomy Centre, University of Sussex, Falmer, Brighton, BN1 9QH (United Kingdom)
Publication Date:
OSTI Identifier:
22382034
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 01; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; DATASETS; FREQUENCY DEPENDENCE; LIMITING VALUES; RELICT RADIATION; SHAPE