Gamma-ray bursts detected from BATSE DISCLA data

California Institute of Technology, Pasadena, CA 91125, U.S.A

Send offprint request to: M. Schmidt

Received: 21 January 1999
Accepted: 28 February 1999

Abstract

We have searched for gamma-ray bursts (GRB) in the BATSE DISCLA data covering the period TJD 8365-10528. We employ an algorithm that uses the background both before and after the onset of the burst, and that requires an excess of at least over background in the energy range 50-300 keV. For the initial set of 7536 triggers, we find strong concentrations at given geographic locations of the satellite. After excluding these geographic areas, we are left with 4485 triggers. We exclude triggers close in position to solar flares, CygX-1, and Nova Persei 1992, when active as well as soft bursts close to the sun. We accept 1018 triggers that occur within 230 s of a GRB listed in the BATSE catalog, and upon visual inspection classify 881 triggers as magnetospheric events and 404 as GRBs. The final sample of 1422 GRBs represents effectively 2.0 years of isotropic exposure, for an annual rate of 710 GRBs per year.