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

We report on the operation of the resonant gravitational wave (g.w.) detector Explorer of the Rome group (M = 2300 kg; T = 2.6 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 h(c) = 8 10(-19) 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. Mie 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.