RXTE/ASM Observations of PSR B1259-63
  RXTE/ASM observations of PSR B1259-63 near the 1997 periastron passage find no emission brighter than appximately 10 times that detected by ASCA during the 1994 periastron encounter, demonstrating that the pulsar is unlikely to have undergone even brief episodes of accretion. 
V. M. Kaspi and R. A. Remillard