New Constraints on Spatial Variations of the Fine Structure Constant
  from Clusters of Galaxies
  We have constrained the spatial variation of the fine structure constant
using multi-frequency measurements of the thermal Sunyaev-Zeldovich effect of
618 X-ray selected clusters. Although our results are not competitive with the
ones from quasar absorption lines, we improved by a factor 10 and ~2.5 previous
results from Cosmic Microwave Background power spectrum and from galaxy
clusters, respectively.
