Letter to the Editor

GRB 021125: The first GRB imaged by INTEGRAL^*

¹ Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF) del CNR, Sezione di Bologna, via Gobetti 101, 40129 Bologna, Italy
² Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF) del CNR, Sezione di Roma, via Fosso del Cavaliere 100, 00133 Roma, Italy
³ INTEGRAL Science Data Centre, Chemin d'Écogia 16, 1290 Versoix, Switzerland
⁴ Institut für Astronomie and Astrophysik, Universität Tübingen, Sand 1, 72076 Tübingen, Germany
⁵ School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
⁶ CEA Saclay, DSM/DAPNIA/SAp, 91191 Gif-sur-Yvette Cedex, France
⁷ Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF) del CNR, Sezione di Milano, via Bassini 15, 20133 Milano, Italy
⁸ Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF) del CNR, Sezione di Palermo, via U. La Malfa 153, 90146 Palermo, Italy
⁹ Centre d'Étude Spatiale des Rayonnements, 9 avenue du Colonel Roche, 31028 Toulouse Cedex 4, France
¹⁰ Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse, 85748 Garching, Germany

Corresponding author: G. Malaguti, malaguti@bo.iasf.cnr.it

Received: 14 July 2003
Accepted: 30 July 2003

Abstract

In the late afternoon of November 25th, 2002 a gamma–ray burst (GRB) was detected in the partially coded field of view (about from the centre) of the imager IBIS on board the INTEGRAL satellite. The instruments on-board INTEGRAL allowed, for the first time, the observation of the prompt gamma-ray emission over a broad energy band from 15 to 500 keV. GRB 021125 lasted ~24 s with a mean flux of ~5.0 photons cm^-2 s^-1 in the 20–500 keV energy band, and a fluence of ~ erg cm^-2 in the same energy band. Here we report the analysis of the data from the imager IBIS and the spectrometer SPI.