GCN Circular 26564
T. Laskar (University of Bath), W. Fong (Northwestern), K. D. Alexander (Northwestern), E. Berger (Harvard), S. Bhandari (CSIRO), G. Hosseinzadeh (Harvard), R. Margutti (Northwestern), C. G. Mundell (University of Bath), and P. Schady (University of Bath) report on behalf of a larger collaboration: "We observed GRB 191221B (Laha et al. GCN 26534) with the Atacama Large Millimeter/Submillimeter Array (ALMA) beginning on 2019 December 22 at 07:43:55 UT (11.1 hr after the burst) at 97.5 GHz under good weather conditions. Preliminary analysis reveals a bright (S/N > 300) mm source at position: 10:19:19.225 (+/- 0.005), -38:09:27.45 (+/- 0.01) consistent with the X-ray position (Beardmore et al. GCN 26540) and optical position (Lipunov et al., GCN 26537). Follow-up observations are planned. We thank the JAO staff, AoD, P2G, and the entire ALMA team for their help with these observations."