Indications of a spatial variation of the fine structure constant
  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.
