Stationarity of asymptotically flat non-radiating electrovacuum   spacetimes
  It is proven that a solution to the Einstein-Maxwell equations whose gravitational and electromagnetic radiation fields vanish is in fact stationary in a neighbourhood of spatial infinity. That is, if the Weyl and Faraday tensors decay suitably fast, then there exists a time-like Killing vector field in the region outside the bifurcate horizon of a sphere of sufficiently large radius. In particular, truly dynamical time-periodic electrovacuum spacetimes do not exist. This is an extension of earlier work by Alexakis and Schlue and Bi\v{c}\'{a}k, Sholtz and Tod to include electromagnetism. 
Rosemberg Toal\'a Enr\'iquez
gr-qc