TITLE: GCN CIRCULAR NUMBER: 20313 SUBJECT: GRB 161219B: VLA Detection DATE: 16/12/21 02:13:57 GMT FROM: Kate Alexander at Harvard K. D. Alexander (Harvard), T. Laskar (NRAO / UC Berkeley), and E. Berger (Harvard) report on behalf of a larger collaboration: We observed the Swift GRB 161219B (D���Ai et al. GCN 20296) at multiple frequencies with the Karl G. Jansky Very Large Array (VLA) beginning 2016 December 20.26 UT (11.4 hours after the burst). At a mean frequency of 14.75 GHz, we detect a radio source with a preliminary flux density of ~0.9 mJy at RA (J2000) = 06:06:51.428 +/- 0.001 Dec (J2000) = -26:47:29.52 +/- 0.01 consistent with the position of the optical afterglow and the refined Swift/XRT position (Beardmore et al. GCN 20297). Follow-up observations are planned. We thank the VLA staff for rapidly executing these observations.