ASCA Discovery of a Be X-Ray Pulsar in the SMC: AX J0051-733
Abstract
ASCA observed the central region of the Small Magellanic Cloud, and found a hard X-ray source, AX J0051-733, at the position of the ROSAT source RX J0050.8-7316, which has an optical counterpart of a Be star. Coherent X-ray pulsations of 323.1 +/- 0.3 s were discovered from AX J0051-733. The pulse profile shows several sub-peaks in the soft (0.7-2.0 keV) X-ray band, but becomes nearly sinusoidal in the harder (2.0-7.0 keV) X-ray band. The X-ray spectrum was found to be hard, and is well fitted by a power-law model with a photon index of 1.0 +/- 0.4. The long-term flux history was examined with the archival data of Einstein observatory and ROSAT; a flux variability with a factor >~ 10 was found.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- December 1999
- DOI:
- 10.1093/pasj/51.6.L15
- arXiv:
- arXiv:astro-ph/9910463
- Bibcode:
- 1999PASJ...51L..15I
- Keywords:
-
- BINARIES: GENERAL;
- PULSARS: INDIVIDUAL (AX J0051-733);
- X-RAYS: GENERAL;
- Astrophysics
- E-Print:
- 6 pages, 5 figures, accepted for publication in PASJ