Measurements with the resonant gravitational wave detector EXPLORER during the gamma-ray burst 980425

¹ Istituto di Astrofisica Spaziale, CNR, via Fosso del Cavaliere, Roma, Italy
² Istituto Astronomico, University of Roma "La Sapienza”, via Lancisi 29, Roma, Italy
³ Istituto Nazionale di Fisica Nucleare (INFN), P.le A. Moro 2, Roma, Italy
⁴ University of Roma "Tor Vergata” and INFN, via O. Raimondo, Roma, Italy
⁵ Istituto di Fisica dello Spazio Interplanetario, CNR, via Fosso del Cavaliere, Roma, Italy
⁶ University of L'Aquila and INFN, via Vetoio (Coppito 1), Coppito di L'Aquila, Italy
⁷ Laboratori Nazionali di Frascati INFN, via E. Fermi 40, Frascati, Italy
⁸ University of Roma "La Sapienza”, P.le A. Moro 2, Roma, Italy
⁹ University of Ferrara, via Paradiso 12, Ferrara, Italy
¹⁰ Istituto TeSRE, CNR, via P. Gobetti 101, Bologna, Italy
¹¹ University of Trieste and INFN, via A. Valerio 2, Trieste, Italy

Send offprint request to: P. Bonifazi

Received: 16 March 1999
Accepted: 5 July 1999

Abstract

We report on the operation of the resonant gravitational wave (g.w.) detector Explorer of the Rome group ( kg,  K, located at CERN) at the time of the gamma-ray burst GRB 980425 (April 25.90915 UT, 1998), which is probably associated with the supernova SN 1998bw. We present the data of the detector (with sensitivity for a 1 ms pulse), and use the BeppoSAX data to estimate the initial time of the GRB: a basic parameter for any correlation analysis. The g.w. data exhibit no significant time signature around the GRB 980425. We wish to remark the importance to make use, in spite of the present low sensitivity, of the data collected with g.w. detectors, that can be regarded as active observatories, in coincidence with the BeppoSAX data.