GCN Circular 32676
Subject
GRB 221009A: NOEMA mm detection
Date
2022-10-11T09:09:27Z (2 years ago)
From
Antonio de Ugarte Postigo at OCA <deugarte@oca.eu>
A. de Ugarte Postigo (OCA), Michael Bremer (IRAM),
C. C. Thoene (ASU-CAS), M. Michalowski (AOI-AMU)
K. Misra (ARIES), S. Antier (OCA), D. A. Kann (Goethe
Univ.), J. F. Agui Fernandez (IAA-CSIC), L. Resmi (IIST),
S. Martin (ALMA), D. A. Perley (LJMU) and S. Schulze
(Uni. of Stockholm) report,
We observed the afterglow of GRB 221009A (Dichiara et al.,
GCN 32632; Kennea & Williams, GCN 32635; Bissaldi et al.,
GCN 32637; Veres et al., GCN 32636; Lesage et al., GCN
32642) with NOEMA at 90 and150 GHz starting at 16:32 UT
of the 10th of October, (27.35 hr after the Fermi GBM trigger;
Veres et al., GCN 32636). The afterglow is strongly detected
at 90 GHz with a flux of ~15 mJy. This is significantly below
the extrapolation of the data reported at lower frequencies in
previous GCNs (Bright et al. GCN 32653; Farah et al., GCN
32655), indicating that our observations are beyond the peak
Frequency, and that the earlier observations may have been
affected by a reverse shock that has already faded.