Bainbridge M. B., Carswell R. F., Flambaum V. V., King J. A., Murphy M. T., Webb J. K. Indications of a spatial variation of the fine structure constant. Vol. 2

We previously reported Keck telescope observations suggesting a smaller value of the fine structure constant, alpha, at high redshift. New Very Large Telescope (VLT) data, probing a different direction in the universe, shows an inverse evolution; alpha increases at high redshift. Although the pattern could be due to as yet undetected systematic effects, with the systematics as presently understood the combined dataset fits a spatial dipole, significant at the 4.2-sigma level, in the direction right ascension 17.5 +/- 0.9 hours, declination −58 +/- 9 degrees. The independent VLT and Keck samples give consistent dipole directions and amplitudes, as do high and low redshift samples. A search for systematics, using observations duplicated at both telescopes, reveals none so far which emulate this result.

DOI:10.1103/PhysRevLett.107.191101
arXiv:1008.3907 [astro-ph.CO]