TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1649 SUBJECT: GRB021021(=XRF 021021): An X-ray Flash Localized by HETE DATE: 02/10/22 11:51:55 GMT FROM: Don Lamb at U.Chicago T. Sakamoto, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K. Torii, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, and T. Donaghy, on behalf of the HETE WXM Team; G. Ricker, J-L Atteia, N. Kawai, D. Lamb, and S. Woosley on behalf of the HETE Science Team; J. Villasenor, R. Vanderspek, J. Doty, G. Crew, G. Monnelly, N. Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE FREGATE Team; write: At 18:43:00.00 UTC (67380.00 s UT) on 21 Oct 2002, the HETE FREGATE and WXM instruments detected a faint, untriggered XRF. Ground analysis of the WXM data for the burst produced a location, which was reported in a GCN Notice at 10:58:44 UT on 22 Oct 2002, about 16 hours after the burst. The WXM localization SNR was 6. The WXM location can be expressed as a 90% confidence circle that is 20 arcminutes in radius and is centered at RA = 00h 17m 23s, Dec = -01d 37' 00" (J2000). In the WXM 2-25 keV band, the burst had a duration of ~13 seconds. The spectrum of the burst is soft, making estimates of its peak flux and fluence uncertain. A light curve for GRB021021 is provided at the following URL: http://space.mit.edu/HETE/Bursts/GRB021021. This message is citable.