Hard X-ray observations of the binary system 4U 1700-377/HD 153919 with the SIGMA Telescope on board GRANAT.
Abstract
In 1990-92, the X-ray source 4U1700-377 was within the field of view of the Sigma telescope during 15 sessions of observations. On September 12, 1990, strong variability of the source was observed in hard X-rays. During the strongest burst, flux from the source increased by about 10 times on a time scale of about 6000 s. On September 27, 1990, variations of the hard X-ray flux were observed with a quasi-period of 5.4 hr. In all other observations, this periodicity was not detected. Approximation of the spectrum with a thermal bremsstrahlung model yields a temperature (characterizing hardness of the spectrum) of about 45 KeV. No variations of the spectrum shape were detected while the source luminosity changed more than an order of magnitude.
- Publication:
-
Astronomy Letters
- Pub Date:
- June 1993
- Bibcode:
- 1993AstL...19..188S
- Keywords:
-
- Light Curve;
- Stellar Luminosity;
- Stellar Spectra;
- Variable Stars;
- X Ray Sources;
- Neutron Stars;
- Spaceborne Telescopes;
- X Ray Astronomy;
- X Ray Telescopes;
- Astronomy