Phase analysis of the cosmic microwave background from incomplete sky coverage

Authors

  • Lung-Yih Chiang,

    Corresponding author
    1. Institute of Astronomy and Astrophysics, Academia Sinica, PO Box 23-141, Taipei 10617, Taiwan
    2. Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
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  • Pavel D. Naselsky

    1. Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
    2. Southern Federal University, Space Research Department, Zorge,5, 344091, Russia
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Both authors contributed equally to this work.

E-mail: lychiang@asiaa.sinica.edu.tw

ABSTRACT

Phases of the spherical harmonic analysis of full-sky cosmic microwave background (CMB) temperature data contain useful information complementary to the ubiquitous angular power spectrum. In this Letter we present a new method of phase analysis on incomplete sky maps. It is based on Fourier phases of equal-latitude pixel rings of the map, which are related to the mean angle of the trigonometric moments from the full-sky phases. It has an advantage for probing regions of interest without tapping polluted Galactic plane area, and can localize non-Gaussian features. This method is therefore very useful for detection of departure from Gaussianity and statistical isotropy in the CMB.

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