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GCN Circular 1168

Subject
GRB001109, Radio Monitoring
Date
2001-11-30T22:36:42Z (22 years ago)
From
Edo Berger at Caltech <ejb@astro.caltech.edu>
E. Berger (Caltech) and D. A. Frail (NRAO) report on behalf of a
larger collaboration:

"We have continued to monitor the radio source detected by Taylor et
al. (VLA J1830+5518; GCN #880) inside the BeppoSAX error box of
GRB001109 (GCN #878) at 1.43, 4.86, and 8.46 GHz with the VLA. This
source had previously been claimed to be the afterglow of GRB001109 by
Rol et al. (GCN #889). Although the mean flux density of the source at
8.46 GHz varies by 10-20%, there has been no secular decrease in the
flux density over a period of 390 days. A similar behavior is observed
at 1.43 and 4.86 GHz.  Moreover, the flux density at 1.43 GHz is
consistently brighter than at 8.46 GHz, with a spectral slope typical
of extragalactic radio sources.  We conclude that this source is not
the afterglow of GRB001109, and therefore the optical galaxy at
z=0.398 associated with it (Vreeswijk et al. GCN #886; Greiner et al.
GCN #887; Afanasiev et al. GCN #1090; Sokolov et al. GCN #1092) is not
a GRB host galaxy."

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