TITLE:   GCN CIRCULAR
NUMBER:  26564
SUBJECT: GRB 191221B: ALMA detection
DATE:    19/12/22 22:36:28 GMT
FROM:    Tanmoy Laskar at U of Bath  <tanmoylaskar@gmail.com>

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."