TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2929 SUBJECT: SGR1806 VLA Observations DATE: 05/01/03 20:43:51 GMT FROM: Chryssa Kouveliotou at MSFC RADIO DETECTION OF SGR 1806-20 FOLLOWING A GIANT FLARE B. M. Gaensler (CfA), C. Kouveliotou (NASA/MSFC, NSSTC), R. Wijers (University of Amsterdam), M. Garrett (JIVE), M. Finger, P. Woods, S. Patel (USRA, NSSTC), M. McLaughlin (Jodrell Bank) report on behalf of a larger team: We observed the soft gamma-ray repeater SGR 1806-20 with the Very Large Array, approximately 7 days after the detection of a Giant Flare from the source (Borkowski, J. et al., 2004, GCN # 2920), on January 3, 2005 for one hour (19:46-20:46 UT). At frequencies of 1.4, 4.9 and 8.5 GHz, we detect an unresolved radio source at coordinates (J2000) RA 18h08m39.3s, Dec -20o24'39.7", with an approximate uncertainty of 0.1" in each coordinate. This is consistent with the X-ray position of SGR 1806-20 as given by Kaplan et al., ApJ 564, 935 (2002). Since this is the first time the source has been observed in radio, we suggest that we detected transient emission from a synchrotron wind bubble, as was seen by Frail et al., Nature, 398, 127 (1999) one to two weeks after a Giant Flare from SGR 1900+14. The preliminary flux density of the source is 160 +/-10, 78 +/-3 and 45 +/-3, mJy at 1.4, 4.9 and 8.5 GHz, respectively. Further observations are planned with the VLA on January 4, 14:15-15:15 UT. We are grateful to the VLA Scheduling Officers (Jim Ulvestadt and Joan Wrobel) for approving our request for Target of Opportunity observations of the source.