NSF-ITP/97-036
astro-ph/9704263

Is there evidence for cosmic anisotropy
in the polarization of distant radio sources?

Sean M. Carroll
Institute for Theoretical Physics, University of California,
Santa Barbara, California 93106, USA
E-mail: carroll@itp.ucsb.edu

George B. Field
Harvard-Smithsonian Center for Astrophysics
60 Garden St., Cambridge, Massachusetts 02138, USA
E-mail: field@cfa.harvard.edu

Abstract:

Measurements of the polarization angle and orientation of cosmological radio sources may be used to search for unusual effects in the propagation of light through the universe. Recently, Nodland and Ralston have claimed to find evidence for a redshift- and direction-dependent rotation effect in existing data. We re-examine these data and argue that there is no statistically significant signal present. We are able to place stringent limits on hypothetical chiral interactions of photons propagating through spacetime.

 
• Introduction
• Data
• Constraints on chiral effects
• Discussion
• Acknowledgments
• References
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