Interstellar scintillation of the radio source associated with the gamma-ray burst of May 8, 1997

The variability of the radio source associated with the gamma-ray burst of May 8, 1997, detected using the VLA, is analyzed. This variability can be explained as weak scintillations at 4.86 and 8.46 GHz and the refractive component of saturated scintillations at 1.43 GHz. Possible distances for the source are discussed. The scintillation parameters are in best agreement with the observations if the source is at a cosmological distance and has an angular size ～2 microarcseconds (µas) at 4.86 GHz and an expansion speed of the order of 25 µas/year.