Published May 10, 1993
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An Observation of the Galactic Center Hard X-Ray Source, 1E 1740.7-2942, with the Caltech Coded-Aperture Telescope
Abstract
The Galactic center region hard X-ray source 1E 1740.7-2942 has been observed with the Caltech Gamma-Ray Imaging Payload (GRIP) from Alice Springs, Australia, on 1988 April 12 and on 1989 April 3 and 4. We report here results from the 1989 measurements based on 14 hr of observation of the Galactic center region. The observations showed lE 1740.7 -2942 to be in its normal state, having a spectrum between 35 and 200 keV characterized by a power law with an exponent of -2.2 ± 0.3 and flux at 100 keV of (7.0 ± 0.7) x 10^(-s) cm^(-2) s^(-1) kev^(-1). No flux was detected above 200 keV. A search for time variability in the spectrum of lE 1740.7-2942 on one hour time scales showed no evidence for variability.
Additional Information
© American Astronomical Society. Provided by the NASA Astrophysics Data System. We acknowledge the important contributions to the development of the GRIP telescope made by W. Althouse, D. Burke, A. Cummings, M. Finger, C. Starr, J. Weger, and the personnel of the Central Engineering Services at Caltech. We thank the personnel of the National Scientific Balloon Facility and the NASA Wallops Flight Facility for their excellent balloon launch support. This work was supported in part by NASA grant NAGW-1919. W. Heindl is supported under the NASA GSRP, NGT-50804.Attached Files
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Identifiers
- Eprint ID
- 45796
- Resolver ID
- CaltechAUTHORS:20140516-102225572
Related works
Funding
- NASA
- NAGW-1919
- NASA
- NGT-50804
Dates
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2014-05-20Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
Caltech Custom Metadata
- Caltech groups
- Space Radiation Laboratory
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 1993-02