Abstract
We previously reported Keck telescope observations suggesting a smaller value of the fine structure constant at high redshift. New Very Large Telescope (VLT) data, probing a different direction in the Universe, shows an inverse evolution; increases at high redshift. Although the pattern could be due to as yet undetected systematic effects, with the systematics as presently understood the combined data set fits a spatial dipole, significant at the level, in the direction right ascension h, declination deg. 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.
- Received 23 August 2010
DOI:https://doi.org/10.1103/PhysRevLett.107.191101
© 2011 American Physical Society