COMPTEL Measurements of the Gamma-Ray Burst GRB 930131
Abstract
On 1993 January 31 at 1857:12 UT, the Imaging Compton Telescope COMPTEL on board the Compton Gamma Ray Observatory (CGRO) detected the cosmic γ-ray burst GRB 930131. COMPTEL's MeV imaging capability was employed to locate the source to better than 2^deg^ (1 σ 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 α_2000_ = 12^h^18^m^, β_2000_ = -9^deg^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: α_2000_ = 12^h^12^m^ and β_2000_ = - 10^deg^21', with a 1 σ error radius of 32'. In COMPTEL's energy range, this burst was short, consisting of two separate spikes occurring within a ~1 s interval with a low intensity tail for ~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 γ-ray flux > 10 MeV place the burst object no farther than 250 pc if the burst emission is not beamed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1994
- DOI:
- 10.1086/187214
- Bibcode:
- 1994ApJ...422L..67R
- Keywords:
-
- Elementary Particle Interactions;
- Gamma Ray Bursts;
- Maximum Likelihood Estimates;
- Photons;
- Triangulation;
- Gamma Ray Observatory;
- Power Spectra;
- Radar Imagery;
- Signal To Noise Ratios;
- Astrophysics;
- GAMMA RAYS: BURSTS