GCN Circular 21545
K.D. Alexander, W. Fong, and E. Berger report on behalf of a larger collaboration: We observed the position of the optical candidate reported by Coulter et al. (LVC GCN 21529) and others (Allam et al. LVC GCN 21530, Valenti et al. LVC GCN 21531, Melandri et al. LVC GCN 21532, and Arcavi et al. GCN 21538) with the Very Large Array beginning at 2017 August 18 02:09:00 UT (13.5 h after the Fermi trigger time). At a mean frequency of 9.77 GHz, we detect a source with a preliminary flux density of ~0.3 mJy at the position: RA (J2000) =13:09:47.850 dec (J2000) =-23:23:01.29 with an error of 1.3" in each coordinate. This is consistent with the optical position reported by Coulter et al. Further observations are planned. We thank the VLA staff for rapidly executing these observations.