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.