A Search for the Radio Counterpart to the 1994 March 1 Gamma-Ray Burst
Cline, T.; Frail, D. A.; Kulkarni, S. R.; Hurley, K. C.; Fishman, G. J.; Kouveliotou, C.; Meegan, C. A.; Sommer, M.; Boer, M.; Niel, M.
United States, Germany, France
Abstract
We report on the results of a search for the radio counterpart to the bright γ-ray burst of 1994 March 1. Using the Dominion Radio Astrophysical Observatory Synthesis Telescope sensitive, wide-field radio images at 1.4 GHz and 0.4 GHz were made of a region around GRB 940301. A total of 15 separate radio images were obtained at each frequency, sampling a near-continuous range of post-burst timescales between 3 and 15 days, as well as 26, 47, and 99 days. We place an upper limit of 3.5 mJy on a fading/flaring radio counterpart at 1.4 GHz and 55 mJy at 0.4 GHz. Unlike past efforts our counterpart search maintains high sensitivity over two decades of post-burst time durations. Time-variable radio emission after the initial γ-ray burst is a prediction of all fireball models, currently the most popular model for γ-ray bursts. Our observations allow us to put significant constraints on the fireball parameters for cosmological models of γ-ray bursts.