Origin of the transient, unpulsed radio emission from the PSR B1259-63 binary system

Abstract

We discuss the interpretation of transient, unpulsed radio emission detected from the unique pulsar/Be star binary system PSR B1259-63. Extensive monitoring of the 1994 and 1997 periastron passages has shown that the source flares over a 100 day interval around periastron, varying on timescales as short as a day and peaking at 60 mJy (∼100 times the apastron flux density) at 1.4 GHz. Interpreting the emission as synchrotron radiation, we show that (i) the observed variations in flux density are too large to be caused by the shock interaction between the pulsar wind and an isotropic, radiatively driven, Be star wind and (ii) the radio-emitting electrons do not originate from the pulsar wind. ..