TITLE: GCN CIRCULAR NUMBER: 15207 SUBJECT: GRB 130907A: WSRT radio detection DATE: 13/09/10 00:48:04 GMT FROM: Alexander van der Horst at U of Amsterdam A.J. van der Horst (University of Amsterdam) reports on behalf of a large collaboration: "We observed the position of the GRB 130907A afterglow at 4.9 GHz with the Westerbork Synthesis Radio Telescope at September 9 09.99 UT to 20.69 UT, i.e. 1.51 - 1.96 days after the burst (GCN 15183). We detect a radio source with a flux density of 0.19 +/- 0.03 mJy at the position of the optical counterpart (GCN 15187). We would like to thank the WSRT staff for quickly scheduling and obtaining these observations."