Search for associations of radio pulses and gamma ray bursts

Continuous radio records obtained between July 1976 and May 1979 by automatic radiometers operating at 151 and 408 MHz from Medicina (Italy) are scanned for radio pulses associated with gamma ray bursts. In all, 65 gamma events are examined. For none of them is a definite association possible with a particular radio pulse detected within plus or minus 10 min from the burst onset. A statistical analysis of the delays between each gamma event and the nearest radio pulse, however, suggests to an 89 percent confidence level that approximately 20 percent of the bursts are associated with a weak radio precursor with a flux density greater than or equal to 10 to the -13th erg/sec sq cm MHz