TITLE: GCN CIRCULAR NUMBER: 22216 SUBJECT: GRB 171205A: VLA detection DATE: 17/12/09 18:19:01 GMT FROM: Tanmoy Laskar at UC Berkeley T. Laskar (NRAO / UC Berkeley), D. L. Coppejans, R. Margutti (Northwestern University), and K. D. Alexander (Harvard) report on behalf of a larger collaboration: "The VLA observed GRB 171205A (D'Elia et al.; GCN 22177) at multiple frequencies from 4.49 GHz to 16.38 GHz beginning on 2017 December 9.58 UT (4.3 days after the burst). At a mean frequency of 6 GHz, we detect a radio source with a preliminary flux density of ~ 3 mJy at RA = 11:09:39.5182 +/- 0.0001 Dec = -12:35:18.480 +/- 0.002 consistent with the Swift/XRT position (Osborne et al.; GCN 22179) and the optical position (Izzo et al.; GCN 222180, Emery et al.; GCN 22181). The spectral index is steeply rising to higher frequencies as nu^2, suggesting a self-absorbed spectrum. Follow-up observations are planned. We thank the VLA staff for rapidly scheduling and executing these service observations."