Phase statistics of the WMAP 7 year data

A. Kovács, I. Szapudi, Z. Frei

Research output: Contribution to journalArticle

3 Citations (Scopus)


We performed a comprehensive statistical analysis using complex phases of the alm coefficients computed from the most recent data of the Wilkinson Microwave Anisotropy Probe (WMAP). Our alm was to confirm or constrain the presence of non-Gaussianities in the data. We found phase correlations - that suggest non-Gaussianity - at high l in alm coefficients by applying various statistical tests. Most of all, we detected a non-Gaussian signal reaching a significance of 4.7σ using random walk statistics and simulations. However, our conclusion is that the non-Gaussian behavior is due to contamination from galactic foregrounds that show up in small scales only. When masked out the contaminated regions, we found no significant non-Gaussianity. Furthermore, we constrained the fNL parameter using CMB simulations that mimic primordial non-Gaussianity. Our estimate is fNL = 40 ± 200, in agreement with previous measurements and inflationary expectations.

Original languageEnglish
Pages (from-to)1020-1023
Number of pages4
JournalAstronomische Nachrichten
Issue number9
Publication statusPublished - Nov 1 2013


  • Astronomical databases: miscellaneous
  • Cosmic microwave background
  • Early Universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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