TITLE: GCN CIRCULAR NUMBER: 21057 SUBJECT: Swift Trigger 748858: 15 GHz upper limits from AMI DATE: 17/05/02 17:26:09 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester) The AMI Large Array responded robotically to Swift trigger 748858 (a possible GRB; Siegel et al., GCN 21011) as part of the 4pisky program, and subsequent follow up observations were obtained up to 10 days post-burst. Our observations at 15 GHz on 2016 Apr 19.79 and Apr 21.09 (UT) do not reveal any radio source in the BAT error circle (Sakamoto et al., GCN 21017), with 3sigma upper limits of 195 uJy and 120 uJy respectively. We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.