The dark side of the bursting pulsar

GRO J1744\\−28 is a unique source appearing as an Xray pulsar and apeculiar burster. This unusual combination is thought to be related to moderatefield Bvirgul5e11G which is higher than in old millisecond, but lower than in normalX ray pulsars. Given field estimate, it the source is expected to switch to thesocalled propeller regime in quiescene, with only nonpulsed thermal emissionfrom neutron stars surface still to be expected. However serendipuousobservations in quiescence revealed a spectrum fully compatible outburstspectrum rather than that expected from a pulsar in propeller . It is thusunclear whether accretion is actually inhibited. We thus propose a 50ksobservation to investigate the physical origin of the observed Xray emission. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]