TITLE: GCN GRB OBSERVATION REPORT NUMBER: 283 SUBJECT: GRB990321 IPN TRIANGULATION DATE: 99/03/23 22:55:15 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Ulysses-GRB team, T. Cline and E. Mazets, on behalf of the KONUS and NEAR GRB teams, report: Ulysses, KONUS-WIND, and NEAR observed a weak, ~20 s long gamma-ray burst on March 21, 1999, which was not observed by BATSE. The Earth-crossing time for this event was 16012 s UT. Triangulation results in two positions, one of which may be eliminated due to the directional response of the two KONUS detectors. (The eliminated position is also consistent with no BATSE detection, as it is Earth-blocked for CGRO.) The remaining error box is rather large (dimensions ~6'x40') due to the weakness of the burst. The preliminary error box corners are given below and the geometry may be viewed at http://ssl.berkeley.edu/ipn3/990321. Some improvement is possible. RA(2000) DEC(2000) 12 H 49 M 36.00 S +80 D 05 M 59.72 S 13 H 01 M 33.51 S +79 D 37 M 25.99 S 13 H 22 M 05.19 S +79 D 03 M 18.34 S 13 H 31 M 36.26 S +78 D 30 M 29.37 S