GCN Circular 10707
Dale A. Frail (NRAO) and Poonam Chandra (RMC) report on behalf of a larger collaboration: "We observed the localization of dark burst GRB 100420A (Baumgartner et al. GCN 10628) with the Expanded Very Large Array (EVLA) on May 1.50 UT at a center frequency of 8.46 GHz. We do not detect any radio source anywhere within the refined XRT error circle (Beardmore et al., GCN 10638) to a 3-sigma limit of 51 uJy. The EVLA is still undergoing active commissioning and we caution that these results should be considered preliminary. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."