Program: GN-2012A-Q-100

Subluminous B stars with massive unseen companions, either massive white dwarfs, neutron stars or black holes are predicted by theory. Several candidate systems have recently been discovered, they have been suggested as progenitors to type Ia Supernovae and Gamma Ray Bursts. We conducted a survey of fast halo subdwarfs in order to find such objects and discovered about 200 binary systems. Here we propose follow-up observations to obtain orbital parameters of those candidates most likely to have massive compact companions.