TITLE: GCN GRB OBSERVATION REPORT NUMBER: 483 SUBJECT: GRB 991216 Radio Observations DATE: 99/12/18 04:44:39 GMT FROM: Greg Taylor at NRAO G. B. Taylor (NRAO) and E. Berger (Caltech) report on behalf of a larger collaboration: "Beginning on December 18.16 UT we observed the field containing the bright BATSE burst GRB 991216 (Kippen et al. GCN 463) using the VLA at 8.5 GHz. We detect a 938 +/- 60 microJy radio source coincident with the optical transient reported by Uglesich et al. (GCN 472). No other radio sources are detected within 2 arcminutes above a 5sigma flux density limit of 300 microJy. The radio afterglow is at ra = 05h09m31.297s dec = +11d17'07.25" (equinox J2000) with a conservative error of 0.1 arcsec in each coordinate. Additional radio observations with the VLA and VLBA are planned." This message may be cited.