EXOSAT observations of five luminous globular cluster X-ray sources.
Abstract
Exosat observations are used to search for orbital modulations in the X-ray light curves of five luminous globular cluster X-ray sources in NGC 1851, NGC 6441, NGC 6712, Terzan 1, and Terzan 2. Upper limits to possible short-period orbital modulation are presented. Two or three intensity dips are observed in the light curve of NGC 6441. The results suggest that these dips are similar to those observed from X 1755-338. It is found that, if the dips are periodic, they result from obscuration of an extended accretion disk corona that contributes more than 15 percent of the observed flux, or from obscuration of the central neutron star by material that is significantly photoionized.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1989
- Bibcode:
- 1989A&A...222...96P
- Keywords:
-
- Exosat Satellite;
- Globular Clusters;
- Light Curve;
- Neutron Stars;
- Satellite Observation;
- X Ray Binaries;
- Accretion Disks;
- Stellar Mass;
- Astrophysics