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TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2358 SUBJECT: GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN DATE: 03/08/22 02:02:16 GMT FROM: Don Lamb at U.Chicago <lamb@oddjob.uchicago.edu> T. Donaghy, C. Graziani, Y. Shirasaki, T. Tamagawa, M. Suzuki, M. Matsuoka, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, Y. Nakagawa, R. Satoh, Y. Urata, T. Yamazaki and Y. Yamamoto, 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; G. Prigozhin, N. Butler, G. Crew, J. Doty, A. Dullighan, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Monnelly, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; C. Barraud, M. Boer, J-F Olive, and J-P Dezalay on behalf of the HETE FREGATE Team; K. Hurley and T. Cline, on behalf of the Ulysses, HETE, Mars Odyssey, and KONUS GRB teams; I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team; W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team; E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team; A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, report: At 05:31:50 UTC (19895.60 s UT) on 21 August 2003, the HETE FREGATE and WXM instruments detected GRB 030821 (=H2814), a faint long GRB. The burst triggered FREGATE in the 25-400 keV energy band. A GCN burst alert was issued 15 s later. The burst was faint and located at the edge of the FOV of the WXM YB counter; hence no WXM flight localization was derived. Ground analysis of the WXM data provided a localization that was reported in a GCN Notice (Seq. 3) at 08:45:53 UT. Mars Odyssey (HEND), Konus-Wind, and INTEGRAL (SPI-ACS) also observed this burst. Triangulation of the burst produces a preliminary annulus centered at RA = 341.285, Dec = -15.283 (J2000), whose radius is 32.642 +/- 1.153 degrees (3 sigma). This annulus does not include the initial (Seq. 3) HETE-2 WXM ground analysis location, but is fully consistent with the revised ground analysis location that was reported in a GCN Notice (Seq. 4) at 22:12:10 UT. The revised WXM ground analysis localization can be expressed as a rectangle that is 33 arcminutes wide and 3.3 degrees long, whose center is at WXM Center-ground: RA = +21h 42m 33s, Dec = -45d 12' 12" (J2000). The four corners of the WXM localization region are located at the following coordinates (J2000): WXM_CORNER1: RA = +21h 41m 48s, Dec = -43d 35' 2" WXM_CORNER2: RA = +21h 45m 58s, Dec = -46d 46' 16" WXM_CORNER3: RA = +21h 43m 16s, Dec = -46d 49' 23" WXM_CORNER4: RA = +21h 39m 10s, Dec = -43d 38' 10" The burst was very faint in the SXC X-camera and was outside the FOV of the SXC Y-camera; hence an SXC localization is unlikely. The T_90 duration of the burst in the 30-400 keV band was ~ 19 s. The peak photon energy flux in 1 s and the fluence of the burst were 4.8 x 10-7 ergs cm-2 s-1 and 5.7 x 10-6 ergs cm-2, respectively, in the same energy band. Ulysses data are expected shortly, and may constrain the localization further. A light curve and finding chart for GRB030821 are provided at the following URL: http://space.mit.edu/HETE/Bursts/GRB030821
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