Title:              The gamma-ray burst of 3 May 1991 observed by
                    COMPTEL on board GRO
Authors:            WINKLER, C.; BENNETT, K.; BLOEMEN, H.; COLLMAR, W.;
                    CONNORS, A.; DIEHL, R.; VAN DORDRECHT, A.; DEN
                    HERDER, J. W.; HERMSEN, W.; KIPPEN, M.
Affiliation:        AB(ESTEC, Noordwijk, Netherlands) AC(Lab. for Space
                    Research, Leiden, Netherlands) AD(Max-Planck-Inst.
                    fuer Extraterrestrische Physik, Garching, Germany)
                    AE(New Hampshire Univ., Durham) AF(Max-Planck-Inst.
                    fuer Extraterrestrische Physik, Garching, Germany)
                    AG(ESTEC, Noordwijk, Netherlands) AI(Lab. for Space
                    Research, Leiden, Netherlands) AJ(New Hampshire
                    Univ., Durham)
Journal:            Astronomy and Astrophysics (ISSN 0004-6361), vol.
                    255, no. 1-2, p. L9-L12.
Publication Date:   02/1992
Origin:             STI
Category:           Astrophysics
NASA/STI Keywords:  GAMMA RAY ASTRONOMY, GAMMA RAY BURSTS, GAMMA RAY
                    OBSERVATORY, GAMMA RAY TELESCOPES, ENERGY SPECTRA,
                    IMAGING TECHNIQUES, INSTRUMENT ERRORS, SPECTRUM
                    ANALYSIS
Bibliographic Code: 1992A&A...255L...9W

Abstract

The Compton Gamma-Ray Observatory was launched on April 5, 1991, carrying
the imaging Compton telescope COMPTEL. Since its activation on April 25,
1991, COMPTEL has observed several gamma-ray bursts in its 1-sr field of
view. The strongest of these bursts was observed on May 3, 1991. Event data
over 0.8 MeV to 30 MeV as well as time resolved spectra over 0.1 MeV to 10
MeV have been recorded. For the first time, a direct single-telescope MeV
image of a cosmic gamma-ray burst has been produced. The burst is located at
(l,b) = (171.8 deg, 6.4 deg) with a statistical uncertainty (99 percent
level) of about 2 deg. The systematic error is about 1 deg, due to the
location of the burst near the edge of the COMPTEL field-of-view. Spectral
analysis indicates that GRB 910503 is a 'classical' hard burst, with
power-law emission up to several MeV, showing 'hard-to-soft' spectral
evolution in its light curve.

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