An observation of the Galactic center hard X-ray source, 1E 1740.7-2942, with the Caltech coded-aperture telescope

Abstract

view Abstract Citations (16) References (36) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An Observation of the Galactic Center Hard X-Ray Source, 1E 1740.7-2942, with the Caltech Coded-Aperture Telescope Heindl, William A. ; Cook, Walter R. ; Grunsfeld, John M. ; Palmer, David M. ; Prince, Thomas A. ; Schindler, Stephen M. ; Stone, Edward C. 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 1E 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 exp -5 sq cm s keV. No flux was detected above 200 keV. A search for time variability in the spectrum of 1E 1740.7-2942 on one hour time scales showed no evidence for variability. Publication: The Astrophysical Journal Pub Date: May 1993 DOI: 10.1086/172608 Bibcode: 1993ApJ...408..507H Keywords: Energy Spectra; Galactic Nuclei; Gamma Ray Telescopes; Milky Way Galaxy; X Ray Sources; Interstellar Radiation; Radiant Flux Density; Astronomy; GALAXY: CENTER; GAMMA RAYS: OBSERVATIONS; X-RAYS: INTERSTELLAR full text sources ADS | data products SIMBAD (10)