TITLE: GCN CIRCULAR NUMBER: 15211 SUBJECT: GRB 130907A: AMI radio detection DATE: 13/09/11 13:29:18 GMT FROM: Alexander van der Horst at U of Amsterdam G.E. Anderson, R.P. Fender, T.D. Staley (University of Southampton), A.J. van der Horst and B.A. Rowlinson (University of Amsterdam) report on behalf of a large collaboration: "We observed the position of the GRB 130907A afterglow at 15 GHz with the Arcminute Microkelvin Imager at September 8 09.90 UT to 11.90 UT, i.e. 12.2 - 14.2 hours after the burst (GCN 15183). We detect a radio source at the position of the optical counterpart (GCN 15187) with a flux density of 1.06 +/- 0.11 mJy. These observations were triggered via the system described in Staley et. al (2013, MNRAS, 428, 3114). Further follow-up observations are planned."