Limits on Reported Transient Emission Events near 0.5 MeV from the Crab and 1E 1740.7-2942

Abstract

view Abstract Citations (14) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Limits on Reported Transient Emission Events near 0.5 MeV from the Crab and 1E 1740.7-2942 Smith, D. M. ; Leventhal, M. ; Cavallo, R. ; Gehrels, N. ; Tueller, J. ; Fishman, G. Abstract The SIGMA coded-mask telescope aboard the Granat observatory has reported transient emission near 0.5 MeV lasting for about 1 day from three Galactic objects: the Crab, black hole candidate Nova Muscae 1991, and, on two occasions, black hole candidate 1E 1740.7-2942 (1E) near the Galactic center. Two of these events (the Crab and one from 1E) have occurred since the launch of the Compton Gamma Ray Observatory (CGRO). Jung et al. searched for the 1E transient of 1992 using the Oriented Scintillation Spectrometer Experiment on CGRO but did not confirm the result. We use the Burst and Transient Source Experiment (BATSE) on CGRO to search for both this event and the Crab transient. We find a 3 σ_upper limit of 1.7 x 10-3 photons s-1 cm-2 compared to the reported flux of (5.1±1.7) x 10-3 photons s-1 cm-2 for the Crab transient, and a 3 σ upper limit of 1.8 × 10-3 photons s-1 cm-2 versus (4.28+2.7-1.5) × 10-3 photons s-1 cm-2 reported for the 1E event. Therefore, we do not confirm the two 1 day SIGMA transients for which BATSE data are available. Publication: The Astrophysical Journal Pub Date: February 1996 DOI: 10.1086/176840 Bibcode: 1996ApJ...458..576S Keywords: GALAXY: CENTER; GAMMA RAYS: OBSERVATIONS; ISM: INDIVIDUAL NAME: CRAB NEBULA; X-RAYS: BURSTS; STARS: INDIVIDUAL CONSTELLATION NAME: NOVA MUSCAE 1991; STARS: INDIVIDUAL ALPHANUMERIC: 1E 1740.7-2942 full text sources ADS | data products SIMBAD (4) HEASARC (1)