Measuring primordial non-Gaussianity in the cosmic microwave background

E. Komatsu, D. N. Spergel, B. D. Wandelt

Research output: Contribution to journalArticle

193 Scopus citations

Abstract

We derive a fast way for measuring primordial non-Gaussianity in a nearly full-sky map of the cosmic microwave background. We find a cubic combination of sky maps combining bispectrum configurations to capture a quadratic term in primordial fluctuations. Our method takes only N3/2 operations rather than N5/2, as taken by the bispectrum analysis (1000 times faster for l = 512), retaining the same sensitivity. A key component is a map of the underlying primordial fluctuations, which can be more sensitive to the primordial non-Gaussianity than a temperature map. We also derive a fast and accurate statistic for measuring non-Gaussian signals from foreground point sources. The statistic is 106 times faster than the full bispectrum analysis and can be used to estimate contamination from the sources. Our algorithm has been successfully applied to the Wilkinson Microwave Anisotropy Probe sky maps by Komatsu and coworkers.

Original languageEnglish (US)
Pages (from-to)14-19
Number of pages6
JournalAstrophysical Journal
Volume634
Issue number1 I
DOIs
StatePublished - Nov 20 2005

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Cosmic microwave background
  • Cosmology: observations
  • Early universe

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