{
  "bibcode": "2005GCN..4145....1D",
  "body": "GRB 051022:  Spectral Analysis Indicates That The Spectrum Is Absorbed\n\nJ. Doty, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on \nbehalf of the HETE Science Team; \n\nM. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, \nN. Ishikawa, A. Kobayashi, J. Kotoku, M. Maetou, M. Matsuoka, \nY. Nakagawa, T. Sakamoto, R. Sato, T. Shimokawabe, Y. Shirasaki, \nS. Sugita, M. Suzuki, T. Tamagawa, K. Tanaka, and A. Yoshida, on behalf \nof the HETE WXM Team; \n\nN. Butler, G. Crew, G. Prigozhin, R. Vanderspek, J. Villasenor, \nJ. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, \nand G. Pizzichini, on behalf of the HETE Operations and HETE \nOptical-SXC Teams; \n\nM. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE \nFREGATE Team; \n\nreport:\n\nWe have performed a spectral analysis of the WXM and FREGATE spectral\ndata for GRB 051022.  Fitting a power-law times exponential (PLE) model\njointly to the WXM and FREGATE spectral data yields a chi^2 of 185 for\n139 DOF, while fitting a PLE model with absorption yields a chi^2 of\n131 for 138 DOF.  Fitting a Band model jointly to the WXM and FREGATE\nspectral data also yields a chi^2 of 131 for 138 DOF.  These results\nshow that the data strongly favor a PLE model with absorption over a\nPLE model alone, and that a PLE model with absorption gives a \nsatisfactory fit to the data.  They also show that the data do not \nrequest a Band model with absorption.\n\nThe best-fit spectral parameters for the PLE model with absorption are\nalpha = -1.22+/-0.02, E_peak = 306 + 31/-26 keV, and n_H = 1.7 � 0.4\nx 10^22 atoms cm^-2.  The fluence is (2.2 � 0.02) x 10^-5 erg cm^-2 \nin the 2-30 keV energy band and (1.4 � 0.02) x 10^-4 erg cm^-2 in the\n30-400 keV energy band.  The ratio log(S_x/S_g) = -1.8, so GRB 051022 \nis a \"classical\" hard GRB.",
  "circularId": 4145,
  "createdOn": 1130040289000,
  "email": "lamb@oddjob.uchicago.edu",
  "subject": "GRB 051022:  Spectral Analysis Indicates That The Spectrum Is Absorbed",
  "submitter": "Don Lamb at U.Chicago  <lamb@oddjob.uchicago.edu>",
  "eventId": "GRB 051022"
}