{
  "bibcode": "2009GCN.10291....1C",
  "body": "J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC),\nW. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),\nH. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),\nD. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),\nG. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),\nT. N. Ukwatta (GWU)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-240 to T+962 sec from the recent telemetry\ndownlink, we report further analysis of BAT GRB 091221 (trigger #380311)\n(Krimm, et al., GCN Circ.#10283).  The BAT ground-calculated position is\nRA, Dec = 55.798, 23.243 deg which is\n    RA(J2000)  =  03h 43m 11.6s\n    Dec(J2000) = +23d 14' 35.2\"\nwith an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 62%.\n\nThe mask-weighted light curve shows a weak peak from T-45 to T-20 sec \nand a stronger, slow-rise, complex peak from T-10 to T+42 sec.  T90\n(15-350 keV) is 68.5 +- 5.5 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T-43.6 to T+41.1 sec is best fit by a \nsimple power-law model.  The power law index of the time-averaged\nspectrum is 1.59 +- 0.06.  The fluence in the 15-150 keV band is\n5.7 +- 0.2 x 10^-06 erg/cm2.  The 1-sec peak photon flux measured from\nT+20.70 sec in the 15-150 keV band is 3.0 +- 0.2 ph/cm2/sec.  All the\nquoted errors are at the 90% confidence level.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/380311/BA/",
  "circularId": 10291,
  "createdOn": 1261500249000,
  "email": "james.r.cummings@nasa.gov",
  "subject": "GRB 091221 Swift-BAT refined analysis",
  "submitter": "Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>",
  "eventId": "GRB 091221"
}