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GCN Circular 32766

GRB 221009A: ATCA radio spectrum
2022-10-15T23:15:43Z (2 years ago)
James Leung at U of Sydney/VAST <>
James Leung (University of Sydney/CSIRO), Tara Murphy (University of 
Sydney), Emil Lenc (CSIRO), Gemma Anderson (Curtin)

We report the radio spectrum for the Australia Compact Telescope Array 
(ATCA) observations (Bhandari et al., GCN 32763) taken on 2022 October
15 from 05:00 to 11:30 UTC (5.6 to 5.9d after the Swift/BAT trigger).

ATCA observed at 16.7, 21.2, 33, 35, 45 and 47 GHz. In our preliminary
analysis, we detect the radio counterpart at each frequency (Trushkin 
et al., ATel 15671; Bright et al., GCN 32653; Farah et al., GCN 32655; 
de Ugarte Postigo et al., GCN 32676; Rhodes et al., GCN 32700; Leung
et al., GCN 32836; Laskar et al., GCN 32740; Laskar et al., GCN 32757;
Urata et al., GCN 32761; Bhandari et al., GCN 32763) at a position 
consistent with the Swift/UVOT position (Dichiara et al., GCN 32632). 

The preliminary flux density measurements are reported below, with 
uncertainties being purely statistical:

7.1 +/- 0.1 mJy/beam at 16.7 GHz
6.1 +/- 0.1 mJy/beam at 21.2 GHz
4.8 +/- 0.1 mJy/beam at 33 GHz
4.4 +/- 0.1 mJy/beam at 35 GHz
3.6 +/- 0.2 mJy/beam at 45 GHz
3.5 +/- 0.2 mJy/beam at 47 GHz

Ongoing observations are planned. 

We thank CSIRO staff for rapidly scheduling, supporting and executing
these observations.

The Australia Telescope Compact Array is part of the Australia Telescope
National Facility which is funded by the Australian Government for
operation as a National Facility managed by CSIRO. We acknowledge the
Gomeroi people as the traditional owners of the Observatory site.
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