The Astrophysical Journal
The American Astronomical Society
The COMPTEL instrument on the Compton Gamma Ray Observatory is used to measure the locations of gamma-ray bursts through direct imaging of MeV photons. In a comprehensive search, we have detected and localized 29 bursts observed between 1991 April 19 and 1995 May 31. The average location accuracy of these events is 1.25◦ (1σ), including a systematic error of ∼0.5◦, which is veriﬁed through comparison with Interplanetary Network (IPN) timing annuli. The combination of COMPTEL and IPN measurements results in locations for 26 of the bursts with an average “error box” area of only ∼0.3 deg2 (1σ). We ﬁnd that the angular distribution of COMPTEL burst locations is consistent with large-scale isotropy and that there is no statistically signiﬁcant evidence of small-angle auto-correlations. We conclude that there is no compelling evidence for burst repetition since no more than two of the events (or ∼7% of the 29 bursts) could possibly have come from the same source. We also ﬁnd that there is no signiﬁcant correlation between the burst locations and either Abell clusters of galaxies or radio-quiet quasars. Agreement between individual COMPTEL locations and IPN annuli places a lower limit of ∼100 AU (95% conﬁdence) on the distance to the stronger bursts.
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