Interpretation of the Global Anisotropy in the Radio Polarizations of Cosmologically Distant Sources

Abstract

We present a detailed statistical study of the observed anisotropy in radio polarizations from distant extragalactic objects. This anisotropy was earlier found by Birch (1982) and reconfirmed by Jain and Ralston (1999) in a larger data set. A very strong signal was seen after imposing the cut $|RM-\overline{RM}|>6$ rad/m${}^2$, where $RM$ is the rotation measure and $\overline{RM}$ its mean value. In this paper we show that there are several indications that this anisotropy cannot be attributed to bias in the data. We also find that a generalized statistic shows a very strong signal in the entire data without imposing the RM dependent cut. Finally we argue that an anisotropic background pseudoscalar field can explain the observations.

arXiv comment13 pages, 6 figures

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Cited by in corpus (3)

• Signals of Statistical Anisotropy in WMAP Foreground-Cleaned Maps
• Probing statistical isotropy of cosmological radio sources using SKA
• A Pixel Space Method for Testing Dipole Modulation in the CMB Polarization