{
  "bibcode": "2003GCN..2442....1T",
  "body": "XRF031109 (=H2919):  A very long XRF localized by HETE\n\nT. Tamagawa, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley\non behalf of the HETE Science Team;\n\nT. Donaghy, C. Graziani, E. Fenimore, M. Galassi, M. Matsuoka, T.\nSakamoto, Y. Shirasaki, M. Suzuki, K. Torii, A. Yoshida, Y. Nakagawa,\nR. Satoh, Y. Urata, T. Yamazaki and Y. Yamamoto, on behalf of the\nHETE WXM Team;\n\nA. Dullighan, R. Vanderspek, G. Crew, J. Doty, G. Prigozhin, J.\nVillasenor, J. G. Jernigan, N. Butler, G. Azzibrouck, J. Braga,\nR. Manchanda, and G. Pizzichini, on behalf of the HETE Operations\nand HETE Optical-SXC Teams;\n\nM. Boer, J-F Olive, J-P Dezalay, C. Barraud, and K. Hurley on behalf\nof the HETE FREGATE Team;\n\nreport:\n\nAt 19:28:59 UTC (70138 s UT) on 9 November 2003, the HETE FREGATE \nand WXM instruments detected event H2919, a very long X-ray Flash (XRF).\n\nThe burst triggered the WXM in the 2-25 keV energy band.  No prompt\nnotification was distributed due to the low image S/N of the burst\nin the flight analysis.  Initial ground analyses showed the burst to \nbe soft, with a duration of ~20s.  Because this burst was detected \nseven minutes before the star cameras had come on line, although the \nWXM data localized the burst to a 15' radius, the original error \nestimate for the celestial coordinates was four degrees.  \n\nFurther analysis of the burst data set has revealed that the burst\ncontinued at a low level for at least seven and perhaps 10 minutes:\nwe estimate t50 to be 310 seconds, t90 to be 480s.  Localization of\nthe photons detected near the end of the burst, and therefore just\nbefore the beginning of star tracker operations, allows the burst to\nbe localized to an error circle of 20' radius centered at\n\n   R.A. = 00h 17m 03s.49,  (J2000)\n   Dec. =  -7o 08' 41\"\n\nAn automated fit of a cutoff power-law spectrum has been performed\nfor H2919.  The fit of the model to the data is posted at\n\n   http://space.mit.edu/HETE/Bursts/GRB031109\n\nThe automated fit for the first 52 seconds of the burst gives the \nfollowing values of Epeak and the burst fluence (25-100 keV):\n\n-- Epeak      = 29 keV\n-- Fluence    = 1.1e-06 erg/cm^2\n\nNB:  The S/N of the fit decreases significantly for longer \n     integration times.\n\nAlso posted at the above website are the following data, in the\nformats described by Vanderspek (GCN 2421):\n\n-- Fregate light curve and ascii data tables (energy bands A [7-30 keV],\n    B [7-80 keV], and C [30-400 keV])\n-- Color-color plot location of H2919 relative to other HETE-localized bursts\n-- Signal-to-noise histogram location of H2919 in Fregate Band C\n    relative to other HETE-localized bursts\n\nThis message may be cited.",
  "circularId": 2442,
  "createdOn": 1068519453000,
  "email": "roland@space.mit.edu",
  "subject": "XRF031109 (=H2919):  A very long XRF localized by HETE",
  "submitter": "Roland Vanderspek at MIT  <roland@space.mit.edu>"
}