TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1734 SUBJECT: GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time DATE: 02/12/11 14:52:49 GMT FROM: Don Lamb at U.Chicago GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time G. Crew, J. Villasenor, R. Vanderspek, J. Doty, 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; G. Ricker, J-L Atteia, N. Kawai, D. Lamb, and S. Woosley on behalf of the HETE Science Team; Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, and T. Donaghy, Y. Nakagawa, D. Takahashi, M. Suzuki, R. Satoh, and Y. Urata, on behalf of the HETE WXM Team; M. Boer, J-F Olive, J-P Dezalay, C. Barraud and K. Hurley on behalf of the HETE FREGATE Team; write: At 11:18:34.03 UTC (40714.03 s UT) on 11 Dec 2002, the HETE FREGATE, WXM, and SXC instruments detected event H2493, a bright, long GRB. The WXM flight localization was correct and was reported in a GCN Position Notice at 11:18:56 UT, 22 sec after the beginning of the burst. Ground analysis of the WXM data for the burst produced a refined location, which was reported in a GCN Notice at 13:29:31 UT, 131 minutes after the burst. The WXM localization SNR was 21. The WXM location can be expressed as a 90% confidence circle that is 5 arcminutes in radius and is centered at RA = +08h 09m 04.8s, Dec = 06d 40'41" (J2000). The uncertainty in the WXM localization is due entirely to systematic error. Ground analysis of the SXC data for the burst produced a further refinement in the location, which was reported in the same GCN Notice at 13:29:31 UT. The SXC localization SNR was 23. The SXC location can be expressed as a 90% confidence circle that is 2 arcminutes in radius and is centered at RA = +8h 09m 00s, Dec = +06d 44' 20" (J2000). The SXC localization may be improved. The location of the optical afterglow candidate reported in GCN 1731 (D. W. Fox and P. A. Price) is offset by 3.2 arcmin from the center of the WXM error circle and 42 arcsec from the center of the SXC error circle. The location of the optical afterglow candidate is therefore fully consistent with the WXM and SXC localizations for GRB021211. The burst duration in the 8-40 keV band was > 5.7 sec. A total of 8310 counts were detected during that interval, corresponding to a fluence of ~1 x 10-6 ergs cm-2 . The peak flux was >8 x 10-7 ergs cm-2 s-1 (i.e., > 20 x Crab flux) in 5msec. A light curve and skymap for GRB021211 is provided at the following URL: http://space.mit.edu/HETE/Bursts/ This message is citable.