A ROSAT observation of the transient X-ray pulsar GRO J1008-57.
Abstract
We report results of a brief Target of Oppurtunity observation of the newly discovered transient X-ray pulsar Gamma Ray Observatory (GRO) J1008-57 using the ROSAT Position Sensitive Proportional Counter (PSPC). The observation was performed well into the decline of the source outburst as monitored by the BATSE hard X-ray light curve. The PSPC cleanly detected the source, at a 0.1-2.4 keV flux of 2.3 x 10-11 erg/sq cm/s. A position centroid accurate to 10 arc seconds has been determined. The 0.1-2.4 keV spectrum is best characterized by a flat power law with substantial interstellar absorption. The PSPC photon index and column density are consistent with that measured at higher energy by ASCA; there is no evidence for an additional soft component. Light-curve folding reveals a period of 93.4 s, consistent with that measured at higher energies; the 0.1-2.4 keV folded light curve shows a high pulsed fraction and a strongly double-peaked pulse profile. The spectral and temporal properties of GRO J1008-57 as observed using the PSPC are entirely consistent with a pulsar orbiting a massive (OB) companion.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1994
- Bibcode:
- 1994A&A...282L..33P
- Keywords:
-
- Binary Stars;
- Pulsars;
- Spaceborne Astronomy;
- Stellar Spectra;
- X Ray Astronomy;
- X Ray Stars;
- Astronomical Spectroscopy;
- Gamma Ray Observatory;
- Light Curve;
- Power Series;
- Proportional Counters;
- Rosat Mission;
- Astronomy