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GCN Circular 2280

GRB 021206, Radio afterglow candidate
2003-06-10T13:09:15Z (20 years ago)
Dale A. Frail at NRAO <>
D. A. Frail (NRAO) reports on behalf of a larger collaboration:

"Using the VLA, we imaged the inner quarter of the initial IPN error
box of the exceptionally bright gamma-ray burst GRB 021206 (Hurley et
al. GCN#'s 1727, 1728). In initial observations made at 4.86 GHz
during the first week after the burst, there was an unresolved radio
source with a flux density of ~400 uJy located at r.a.=16:00:46.85,
dec.=-09:42:33.5 (J2000), with an uncertainty of about 0.6 arcsec.
Subsequent measurements at 4.86 and 8.46 GHz in February and March
2003 showed that the source has faded by a least a factor of five.
Future observations are planned to place tighter limits on the flux
density of this radio source.

Although the magnitude of the radio flux density and the temporal
behavior of the light curve are typical of past GRB afterglows, we
cannot rule out the possibility (probability <=0.02) that this is an
unrelated background variable (Frail et al. AJ, 125, 2299, 2003).
Given the recent RHESSI detection of polarized emission from this
burst (Coburn & Boggs, Nature, 423, 415, 2003) we encourage further
followup optical observations of this candidate afterglow."

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