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TO: All GCN Circulars recipients My apologies to those of you receiving these Circulars a second time. There was a problem with the free-space on the disk partition on the machine that runs the GCN Circulars program today. There was a brief period of time (about an hour) when the free space for email send-queue spool directory went to zero. The circulars are archived on the GCN web site. But since these are important Circulars (e.g. containing HETE flux measurements and RXTE afterflow dection), I am taking the liberty of redistributing them so that the community is aware of the information. Sincerely, Scott Barthelmy GCN OPS ///////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1997 SUBJECT: GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC DATE: 03/03/29 19:53:03 GMT FROM: Don Lamb at U.Chicago <lamb@oddjob.uchicago.edu> R. Vanderspek, G. Crew, J. Doty, J. Villasenor, 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; T. Donaghy, M. Suzuki, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, Y. Nakagawa, D. Takahashi, 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 11:37:14.67 UTC (41834.67 s UT) on 29 Mar 2003, the HETE FREGATE, WXM, and SXC instruments detected event H2652, a long, extremely bright GRB. The burst triggered FREGATE in the 6-120 keV energy band. The burst occurred outside of the effective FOV of the WXM Y-camera. Ground analysis of the SXC data produced a localization that was reported in a GCN Notice at 12:50:24 UT, 73 minutes after the burst. The SXC ground localization SNR was 20. Further ground analysis of the SXC data has provided an SXC localization that can be expressed as a 90% confidence circle that is 2 arcminutes in radius and is centered at SXC-Ground: RA = +10h 44m 50s, Dec = +21d 30' 54" (J2000). The SXC localization is dominated by systematic errors, which are larger than usual because the burst occurred at the edge of the SXC FOV. (The error circle radius of 2 arcminutes reported in the GCN Notice for H2652 did not include the larger systematic errors.) Ground analysis of the WXM data produced a WXM localization. The WXM ground localization SNR is > 20. The WXM localization can be expressed as a 90% confidence rectangle that is 12 arcminutes in width and 2.25 degrees in length. The center of the rectangle lies at WXM-Ground: RA = +10h 44m 24.7, Dec = +23d 20' 20" (J2000), and its corners lie at RA = +10h 44m 39.6s, Dec = +23d 29' 20", RA = +10h 43m 53.5s, Dec = +23d 26' 35", RA = +10h 44m 09.8s, Dec = +21d 11' 38", RA = +10h 44m 55.9s, Dec = +21d 14' 17" (J2000). The width of the WXM localization is dominated by systematic errors, which are larger than usual because the burst occurred at the edge of the WXM FOV. The WXM localization is a long, narrow strip because the burst occurred at the edge of the WXM FOV in a region of the sky that would have been viewed by the YB-camera, which is not operational. The burst duration in the 30-400 keV band was > 25 s. The fluence of the burst was ~1 x 10-4 ergs cm-2 and the peak flux over 1.2 s was > 7 x 10-6 ergs cm-2 s-1 (i.e., > 100 x Crab flux) in the same energy band. A light curve and skymap for GRB030329 is provided at the following URL: http://space.mit.edu/HETE/Bursts/GRB030329 ///////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1996 SUBJECT: RXTE detection of GRB 030329 afterglow DATE: 03/03/29 19:37:01 GMT FROM: Frank Marshall at GSFC <marshall@milkyway.gsfc.nasa.gov> Marshall, F.E. and Swank, J.H. (NASA/GSFC) report: RXTE detected the X-ray afterglow of GRB 030329 (HETE trigger 2652) during a 27 minute observation that began about 4h51m after the burst at 16:28 UT on March 29 . The flux was about 1.4e-10 ergs/s/cm**2 in the 2-10 keV band or about 0.007 times as bright as the Crab Nebula. This is one of the brightest afterglows ever detected with RXTE. The spectrum is well fit by a power law model with a photon index of 2.0 and an upper limit on absorption of 1e22 Nh/cm**2. The X-ray flux was about 20% lower during a second observation starting at 17:32 UT. This message may be cited.
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