TITLE: GCN GRB OBSERVATION REPORT NUMBER: 271 SUBJECT: GRB990308, Possible new SGR~0209+70 DATE: 99/03/08 22:07:34 GMT FROM: David Palmer at USRA/GSFC On behalf of the Konus team, David Palmer writes: Konus has detected two series of short spike bursts (typically shorter than the 64 ms sampling time) on 1999 March 7 & 8. One such series begins on 990307 at Seconds of Day (SOD) 62019.5, with subsequent bursts at +12, +20, +57 (double spike), +72, and +87 (positive flux in 4 consecutive 64 ms samples) seconds later. The fine time resolution sampling ends at +100 seconds. The spikes at +20 and +87 seconds each exceed 200 counts per sample. The second series begins at 990308 SOD 11094.5, with a complex burst, with subsequent peaks at +2, +6, +21 and +28 seconds. The initial burst of the second series corresponds to BATSE #7456 (990308_11093), which has a final estimated position of (RA, dec) = (24.8,+67.8) degrees J2000. This is just barely above the horizon as seen by BATSE at that time, and subsequent spikes may have been blocked by Earth occultation. BATSE #7460 (990308_71254) has a final position of (RA,Dec)=(39.8,+71.6) or 6 degrees away from the final BATSE #7456 position. This is consistent with the measurement accuracy, and improbable for two independent bursts on the same day at better than the 95% level, with the usual caveats about post-prior probabilities. The mean location is 8 degrees from the Galactic plane. All of these properties are consistent with a proposed source identification as a previously-unknown SGR. Observations of this sky location with other high-energy instruments are requested. David Palmer palmer@lheamail.gsfc.nasa.gov USA (301) 286-2739 Voice USA (301) 286-1684 Fax