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GCN Circular 230

GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
1999-01-26T22:15:07Z (25 years ago)
Alanna Connors at UNH <>
A. Connors and R. M. Kippen, for the CGRO-COMPTEL Rapid Burst Response
collaboration; and S. Barthelmy and P. Butterworth, for BACODINE/GCN,
report the following:

CGRO-COMPTEL observed GRB 990123 to be extremely bright in its ~MeV energy
range.  The >0.7 MeV emission rose about 18 seconds after the initial BATSE 
trigger at 9h 46m 56.12s U.T. and lasted about 46 seconds, for a 10 sigma
detection, despite its very large zenith angle (59 degrees).  An initial 
detection notice was sent about 10 minutes after burst onset.  Improved
skymaps and light-curves for the full 0.2-30 MeV range have now been posted
at the CGRO-COMPTEL Rapid Burst Response web-site: 

These are still considered preliminary as our standard energy calibration is
not yet complete.

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