TITLE: GCN CIRCULAR NUMBER: 12421 SUBJECT: GRB 111005A: ATCA radio upper limit DATE: 11/10/07 12:15:26 GMT FROM: Dong Xu at Weizmann Inst D. Xu (WIS), M. Michalowski (U. Edinburgh), J. Stevens, P. Edwards, D. Bock, B. Hiscock, R. Wark (CSIRO) report on behalf of a larger collaboration: We observed the BAT field of GRB 111005A (Saxton et al., GCN 12413) with the Australia Telescope Compact Array (ATCA), starting at 05:13 UT, 7th Oct. 2011 (i.e., 45.1 hours after the burst) at frequencies of 5.5/9 GHz. The source of NVSS 145310-194331, or EVLA-S2 by Zauderer et al. (GCN 12419), in the field was clearly detected in our 5.5GHz image. But no radio source was detected near or in the local galaxy, ESO 580-49 at z=0.013 (Levan et al., GCN 12414), to a 3sigma upper limit of ~114 microJy at 5.5GHz. Comparison with the earlier detection of a radio transient, EVLA-S1, in the galaxy (GCN 12419; and typical EVLA 3sigma upper limit of ~60-100 microJy from previous GRB events) reveals that probably this radio transient has been decaying over the past ~2 days. Further ATCA observations of the field are underway.