Gamma-ray burst arrival-time localizations: Simultaneous observations by Ulysses, Pioneer Venus Orbiter, SIGMA, WATCH, and PHEBUS

Between the launch of the Ulysses spacecraft in 1990 October and the entry of Pioneer Venus Orbiter (PVO) into the atmosphere of Venus in 1992 October , concurrent coverage by Ulysses, PVO, the WATCH experiments aboard the Gra nat and Eureca spacecraft, and the SIGMA and PHEBUS experiments aboard the Granat spacecraft was obtained for numerous gamma-ray bursts. Fifteen of th em were detected by three or more instruments on spacecraft separated by di stances of several AU and could therefore be accurately localized by triang ulation. In some cases, independent, accurate locations were obtained by SI GMA and/or WATCH. We present these localizations, which range in area from 0.9 to 530 arcmin(2).