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GCN Circular 5871

Subject
GRB 061121: ATCA & WSRT Radio Observations
Date
2006-11-27T15:58:28Z (18 years ago)
From
Alexander van der Horst at U of Amsterdam <avdhorst@science.uva.nl>
A.J. van der Horst, R.A.M.J. Wijers (University of Amsterdam) and E. Rol
(University of Leicester) report on behalf of a larger collaboration:

"We observed the position of the GRB 061121 afterglow (GCN 5823) at
2.3 GHz with the Westerbork Synthesis Radio Telescope, and at 4.8 and
8.6 GHz with the Australia Telescope Compact Array.
We do not detect a radio counterpart of the optical afterglow (GCN 5824).
Our results are given in the table below. We note that the three-sigma
flux limit at 8.6 GHz at ~5.2 days after the burst is significantly
lower than the VLA detection at ~0.8 days after the burst (GCN 5843).

Epoch            Delta T   Frequency  3-sigma rms noise  Formal flux
===============  ========  =========  =================  ==============
Nov 26.76-26.92  5.2 days  8.6 GHz    246 uJy/beam        10 +/- 82 uJy
Nov 26.76-26.92  5.2 days  4.8 GHz    210 uJy/beam        13 +/- 70 uJy
Nov 27.01-27.30  5.5 days  2.3 GHz    144 uJy/beam       -50 +/- 48 uJy


We would like to thank the WSRT staff for obtaining these observations
in between VLBI observation runs. Also we would like to thank the staff
of the Australia Telescope National Facility, in particular Philip
Edwards, for obtaining these Target of Opportunity observations."
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