{
  "bibcode": "2003GCN..2027....1F",
  "body": "GRB030328: X-ray Fading and Spectrum Measured with Chandra\n\nP. G. Ford, N. R. Butler, H. L. Marshall, R. K. Vanderspek, G. R.\nRicker (MIT), J. G. Jernigan (U.C. Berkeley), and D. Q. Lamb (U. Chicago)\n\nreport:\n\nAs reported in Butler et al. (GCN 2007), Chandra LETGS observations \ncommenced on March 29.112 (t[burst] + 15.33 hr) of a field centered \non the HETE WXM+SXC error region (Villasenor et al, GCN 1978) for \nGRB030328.  We report here on the first 39.7 ksec of data, which was \ntaken until March 29.744 (t[burst] + 30.51 hr).  The relatively faint \nX-ray afterglow reported in GCN 2007 is observed to fade in \nbrightness according to a power-law with a decay slope of -1.5 +/- \n0.3.  (This value is consistent with the decay slope value of -1.6 \nfound by Andersen et al. (GCN 1993) in the optical.)  The mean \ncounting rate was 0.023 counts/s (summed over the dispersed signal \nfrom the LETGS, and including the 0th order flux).  The source \nspectrum, which we derive from our preliminary analysis of the \ndispersed LETGS counts, is characterized as follows:\n\nnH = 4.32 x 10^20 cm^(-2), fixed at the Galactic value in the source direction;\n\ndN/dE = A * E^ (-gamma) ph cm^(-2) s^(-1) keV^(-1) ,\nover the 0.8-2.7 keV range, with A = 0.0001, and gamma = 1.80\n\nThus, the mean flux for the 0.8 to 2.7 keV band over the duration of\nthe Chandra observation was ~1.7 x 10^(-13) ergs cm^(-2) s^(-1).\n\nOur analyses are continuing, and more detailed results will be posted at:\n\nhttp://space.mit.edu/HETE/\n\nWe thank Harvey Tananbaum for his generous allocation of Director's\nDiscretion Time to this observation, and the Chandra X-ray\nObservatory Operations personnel for the impressive promptness with\nwhich this observation was planned and carried out.\n\nThe preliminary results reported here may be cited.",
  "circularId": 2027,
  "createdOn": 1049049326000,
  "email": "grr@space.mit.edu",
  "subject": "GRB030328: X-ray Fading and Spectrum Measured with Chandra",
  "submitter": "George Ricker at MIT  <grr@space.mit.edu>",
  "eventId": "GRB 030328"
}