TITLE: GCN CIRCULAR NUMBER: 33475 SUBJECT: GRB 230307A: ATCA radio detection DATE: 23/03/14 05:23:06 GMT FROM: Gemma Anderson at Curtin U G. E. Anderson (Curtin Uni.), J. K. Leung (U. Sydney), T. Murphy (U. Sydney), E. Lenc (CSIRO) L. Rhodes (U. Oxford), A. J. van der Horst (GWU), G. Rowell (U. Adelaide) We observed GRB 230703A (Fermi GBM Team GCN 33405) with the Australia Telescope Compact Array (ATCA) between 2023-03-12_02:30 UT and 2023-03-12_07:30 UT (~4.5 days post-burst). In our preliminary analysis, we detect a radio source coincident with the X-ray (Burrows et al. GCN 33429, GCN 33465) and optical (Levan et al. GCN 33439) counterpart with a flux density of 120+/-30 microJy/beam at 9 GHz. We also obtain an 3 sigma upper limit of 90 microJy/beam at 5.5 GHz. We thank CSIRO staff for supporting these observations. The ATCA is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi people as the traditional owners of the Observatory site.