[vsnet-grb-info 19706] GRB 170728B: 15 GHz upper limits from AMI

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21466
SUBJECT: GRB 170728B: 15 GHz upper limits from AMI
DATE:    17/08/11 18:16:52 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley at physics.ox.ac.uk>

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 robotically triggered on the Swift alert for the 
short GRB 170728B (Cenko et al., GCN 21371) as part of the 4pisky 
program, and subsequent follow up observations were obtained up to 3 
days post-burst. Our observations at 15 GHz on 2017 Jul 29.00, Jul 
29.80, Jul 30.80 and Jul 31.76 (UT) do not reveal any radio source at 
the XRT location (Osborne et al., GCN 21377), with 3sigma upper limits 
of 258 uJy, 201 uJy, 171 uJy and 108 uJy respectively. This upper limit 
is consistent with the radio afterglow detection on 2017 Jul 29.81 
reported by Fong et al. (GCN 21395; much fainter than 300 uJy at 6 GHz).

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/.