TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1168 SUBJECT: GRB001109, Radio Monitoring DATE: 01/11/30 22:36:42 GMT FROM: Edo Berger at Caltech 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." This message may be cited.