GCN Circular 1613
Subject
GRB 021004 - VLA Radio Observations
Event
Date
2002-10-10T06:31:25Z (23 years ago)
From
Edo Berger at Caltech <ejb@astro.caltech.edu>
E. Berger, D. A. Frail, and S. R. Kulkarni report on behalf of a larger
collaboration:
"We observed the radio afterglow of GRB 021004 (Frail & Berger GCN 1574;
Berger, Kulkarni, & Frail GCN 1612) with the VLA at 1.43, 4.86, and 8.46
GHz on October 10.17 UT. We measure the following flux densities:
F(1.43)=48+/-53 microJy, F(4.86)=359+/-38 microJy, and F(8.46)=598+/-33
microJy. The resulting spectral slope is beta~1 (F_nu~nu^beta), in
excellent agreement with the unusual value of beta=0.9 between 8.5 and 86
GHz measured by Berger, Kulkarni, & Frail (GCN 1612). This again
indicates that the spectrum is not due to a transition from
optically-thick (nu^2) to optically-thin (nu^1/3) emission, and it further
highlights the unusual nature of this radio afterglow."
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