Upper Limit for the Pulsed Emission above 100 keV from Hercules X-1
Abstract
We report a search for the 1.24 s pulsed emission above 100 keV from the binary X-ray source Hercules X-l. This source was discovered and has been extensively observed by the Uhuru satellite in the 2 to 20 keV region1,2. Hard X-ray observations have been reported by the MIT and UCSD experiments on the OSO-7 satellite3-5 and by balloon-borne experiments6,7. These hard X-ray observations reflect only the time-averaged flux; no pulsed emission has been reported. The observed spectrum steepens at ~35 keV, and is most consistent with a thermal bremsstrahlung model.
- Publication:
-
Nature Physical Science
- Pub Date:
- October 1973
- DOI:
- 10.1038/physci245116a0
- Bibcode:
- 1973NPhS..245..116K