  We study N <= 2 superconformal and supersymmetric theories on Lorentzian
threemanifolds with a view toward holographic applications, in particular to
BPS black hole solutions. As in the Euclidean case, preserved supersymmetry for
asymptotically locally AdS solutions implies the existence of a (charged)
"conformal Killing spinor" on the boundary. We find that such spinors exist
whenever there is a conformal Killing vector which is null or timelike. We
match these results with expectations from supersymmetric four-dimensional
asymptotically AdS black holes. In particular, BPS bulk solutions in global AdS
are known to fall in two classes, depending on their graviphoton magnetic
charge, and we reproduce this dichotomy from the boundary perspective. We
finish by sketching a proposal to find the dual superconformal quantum
mechanics on the horizon of the magnetic black holes.
