Confirmation of isolated black holes and neutron stars detected via microlensing

Discovery of isolated black holes resembles finding a Holly Grail. InWyrzykowski et al. (2015) we have selected 15 candidates for dark remnants basedon microlensing effect observations, however, the lens mass estimates span alarge range in mass, affecting the interpretation on their nature. Here wepropose XMM observations of 5 of the best candidates for isolated black holes todetect theoretically predicted BondiHoyle accretion. Additional AO observationsobtained with VLT/NACO will complement the interpretation of the Xray data andwill allow to confirm/reject the candidates for isolated black holes and neutronstars and to further constrain their masses. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]