{
  "bibcode": "2005GCN..3062....1S",
  "body": "T. Sakamoto, S. Barthelmy, N. Gehrels, J. Cummings, A. Parsons, \nJ. Tueller (GSFC), E. Fenimore, D. Palmer (LANL), D. Hullinger, \nC. Markwardt (GSFC/UMD), H. Krimm (GSFC/USRA), G. Sato (ISAS), \nM. Suzuki (Saitama) \n\nWith the further analysis of the BAT spectral data of GRB050215b, \nwe confirmed the nature of X-ray flash for GRB050215b.   \n\nIf we used the best fit Epeak energy of 17.6 keV derived from the HETE \ndata (Nakagawa et al, Circ 3053), the transition energy between the \nlower energy cutoff power-law component and the higher energy power-law \ncomponent of the Band function (Band et al. 1993) will be 26.4 keV if we \nassume alpha=-1 and beta=-2.5.  Based on this estimation, we tried to fit \nthe BAT spectrum only using above 30 keV to see the evidence of the \npower-law slope of steeper than -2.  \n\nWith this fit, we obtained the best fit power-law index of -2.99 \n(-1.02/+0.77; 90% confidence).  The significance in the power-law \nindex of steeper than -2.0 is 97%.  This is a strong indication \nthat BAT observed the higher portion of the Band function, and the \nEpeak of GRB050215b is indeed below 30 keV.",
  "circularId": 3062,
  "createdOn": 1109204530000,
  "email": "takanori@milkyway.gsfc.nasa.gov",
  "subject": "Confirmed XRF nature for GRB050215b",
  "submitter": "Takanori Sakamoto at NASA/GSFC  <takanori@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 050215B"
}