TITLE:   GCN CIRCULAR
NUMBER:  30423
SUBJECT: GRB 210702A: ALMA detection
DATE:    21/07/08 18:26:27 GMT
FROM:    Tanmoy Laskar at U of Bath  <tanmoylaskar@gmail.com>

T. Laskar (University of Bath) and D. Perley (LJMU) report on behalf of a
larger collaboration:

"We observed GRB 210702A (Lien et al. GCN 30351) with the Atacama Large
Millimeter/Submillimeter Array (ALMA) at 97.5 GHz and 343.5 GHz beginning
on 2021 July 03 21:05:52 UT (26.0 h after the burst). ALMA observations of
this burst were delayed due to uninterruptible scheduled Cycle 8 software
validation at the Observatory.

Preliminary analysis reveals a mm source with flux density of ~ 0.1 mJy at
97.5 GHz and position:

RA (J2000) = 11:14:18.807
Dec (J2000) = -36:44:49.25

with uncertainty ~ 0.03" in each coordinate, consistent with the X-ray
position (D'Elia et al., GCN 30358) and optical position (Lien et al., GCN
30351; Kuin et al., GCN 30356). The spectrum appears strongly self-absorbed
in the mm-band. Further observations are planned.

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