COMPTEL Locations and Spectra of Gamma-Ray Bursts

Previous abstract Next abstract

Session 53 -- Gamma Ray Bursts
Oral presentation, Thursday, June 15, 1995, 10:00am - 11:30am

[53.06] COMPTEL Locations and Spectra of Gamma-Ray Bursts

R.M. Kippen, J. Ryan, A. Connors, M. McConnell (UNH), C. Winkler, L.O. Hanlon (SSD-ESA/ESTEC), J. Greiner, V. Sch\"onfelder, M. Varendorff, W. Collmar (MPE), W. Hermsen, L. Kuiper (SRON-Utrecht)

In its first three years of operation, the COMPTEL instrument aboard Compton\/ Gamma-Ray Observatory has measured the locations (mean accuracy $\sim$1$\deg$) and spectra (0.75--30 MeV) of 18 gamma-ray bursts and continues to observe new events every $\sim$1--2 months. The COMPTEL burst locations are consistent with an isotropic angular distribution of sources, yet the spatial coincidence of two of the bursts indicates the possibility of recurrence. The time-averaged COMPTEL burst spectra are consistent with a single power law model above 1 MeV with spectral index in the range 2--3. Measurement of rapid variability at MeV energies in the stronger bursts provides evidence that either the sources are nearby (within the Galaxy) or the gamma-ray emission is relativistically beamed. We review recent analysis results obtained from the existing COMPTEL burst catalog and give an update on new observations, including the on-going search for fading low-energy counterparts using rapidly-determined COMPTEL burst locations.

Thursday program listing