TITLE:   GCN CIRCULAR
NUMBER:  32577
SUBJECT: GRB 220921A: ALMA detection
DATE:    22/09/23 16:37:36 GMT
FROM:    Tanmoy Laskar at U of Bath  <tanmoylaskar@gmail.com>

T. Laskar (University of Utah), K. D. Alexander (University of Arizona), E.
Berger (Harvard University), R. Chornock (UC Berkeley), W. Fong
(Northwestern University), R. Margutti (UC Berkeley), C. G. Mundell
(University of Bath), and P. Schady (University of Bath) report on behalf
of a larger collaboration:

"We observed GRB 220921A (Pillera et al., GCN 32568) with the Atacama Large
Millimeter/Submillimeter Array (ALMA) at 97.5 GHz beginning on 2021
September 23 08:04 UT (45 h after the burst). Preliminary analysis reveals
a mm source with flux density of ~ 0.7 mJy at position:

RA (J2000) = 04:25:53.42
Dec (J2000) = -40:24:20.25

with uncertainty ~ 0.01" in each coordinate, consistent with the X-ray
position (N. Klinger, GCN 32571) and optical position (Lipunov et al., GCN
32570). Further observations are planned.

We thank the JAO staff, AoD, P2G, and the entire ALMA team for their help
with these observations."