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), have been scanned for radio pulses associated with gamma ray bursts. Sixty five gamma events have been examined. For none of them a definite association with a particular radio pulse detected within ±10 min from the burst onset has been possible. However, a statistical analysis of the delays between each gamma event and the nearest radio pulse suggests to a 89% confidence level that about 20% of the bursts are associated with a weak radio precursor with flux density ≥10−13 erg/sec cm2 MHz.