COMPTEL MEASUREMENTS OF THE GAMMA-RAY BURST GRB-930131

On 1993 January 31 at 1857:12 UT, the Imaging Compton Telescope COMPTEL onboard the Compton Gamma Ray Observatory (CGRO) detected the cosmic gamma-ray burst GRB 930131. COMPTEL's MeV imaging capability was employed to locate the source to better than 2-degrees (1 sigma error radius) within 7 hr of the event, initiating a world-wide search for an optical and radio counterpart. The maximum likelihood position of the burst from the COMPTEL data is alpha2000 = 12h18m, delta2000 = -9-degrees-42', consistent with independent CGRO-BATSE and EGRET locations as well as with the triangulation annulus constructed using BATSE and Ulysses timing data. The combined COMPTEL and EGRET burst data yield a better estimate of the burst location: alpha2000 = 12h12m and delta2000 = -10-degrees-21', with a 1 sigma error radius of 32'. In COMPTEL's energy range, this burst was short, consisting of two separate spikes occurring within a approximately 1 s interval with a low intensity tail for approximately 1 s after the second spike. No statistically significant flux is present for a 30 s period after the main part of the burst. This is consistent with the EGRET data. The COMPTEL telescope events indicate a hard, power-law emission extending to beyond 10 MeV with a spectral index of -1.8 +/- 0.4. The rapid fluctuations and high intensities of the gamma-ray flux > 10 MeV place the burst object no farther than 250 pc if the burst emission is not beamed.