Variations on spacetimes with boost-rotation symmetry
  Some new results on the boost-rotation symmetric spacetimes representing pairs of rotating charged objects accelerated in opposite directions are summarized. A particular attention is paid to (a) the Newtonian limit analyzed using the Ehlers frame theory and (b) the special-relativistic limit of the C-metric. Starting from the new, simpler form of the rotating charged C-metric we also show how to remove nodal singularities and obtain a rotating charged black hole freely falling in an external electromagnetic field. 
Ji\v{r}\'i Bi\v{c}\'ak and David Kofro\v{n}
gr-qc