GCN Circular 21589
K.D. Alexander (Harvard), W. Fong (Northwestern), and E. Berger (Harvard) report on behalf of a larger collaboration: We analyzed observations taken with the Very Large Array beginning on 2017 Aug 18 at 22:04:57 UT (1.39 d after the Fermi trigger time; Blackburn et al., LVC GCN 21506). In two hours of observations at a mean frequency of 10.0 GHz, we detect the source reported in our previous VLA observations (Alexander et al., LVC GCN 21545; 21548) and in ATCA observations (Bannister et al., LVC GCN 21559) at a similar flux level. We measure an improved position of: RA = 13:09:47.704 Dec =-23:23:02.45 with an uncertainty of 0.1��� in each coordinate. We note that the beam size in our images is 3.1��� by 1.4���, significantly smaller than our previous VLA observations. The lack of variability over a 19.9 hr period along with full spatial coincidence with NGC 4993 indicates that this radio emission is originating from the host galaxy. We further note that there is no detected emission at the position of the optical transient (Coulter et al., LVC GCN 21529) down to a 3-sigma limit of 17 microJy.