{
  "bibcode": "2015GCN.18752....1K",
  "body": "H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),\nN. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),\nD. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL)\n(i.e. the Swift-BAT team):\n \nUsing the data set from T-61 to T+243 sec from the recent telemetry downlinks,\nwe report further analysis of BAT GRB 151228B (trigger #668641)\n(Lien, et al., GCN Circ. 18739).  The BAT ground-calculated position is\nRA, Dec = 344.431, 8.081 deg, which is \n   RA(J2000)  =  22h 57m 43.4s \n   Dec(J2000) = +08d 04' 52.4\" \nwith an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 100%.\n \nThe mask-weighted light curve shows a FreD-like peak starting at ~T-10 sec,\npeaking at ~T+3 sec, and ending at ~T+65 sec.  T90 (15-350 keV) is\n48.0 +- 16.0 sec (estimated error including systematics).\n \nThe time-averaged spectrum from T-12.56 to T+67.44 sec is best fit by a power law\nwith an exponential cutoff.  This fit gives a photon index 1.09 +- 0.34, \nand Epeak of 78.1 +- 27.0 keV (chi squared 52.3 for 56 d.o.f.).  For this\nmodel the total fluence in the 15-150 keV band is 2.4 +- 0.1 x 10^-6 erg/cm2\nand the 1-sec peak flux measured from T+10.94 sec in the 15-150 keV band is\n1.0 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index\nof 1.66 +- 0.08 (chi squared 61.6 for 57 d.o.f.).  All the quoted errors\nare at the 90% confidence level. \n \nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/668641/BA/",
  "circularId": 18752,
  "createdOn": 1451399399000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 151228B: Swift-BAT refined analysis",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 151228B"
}