{
  "bibcode": "2014GCN.17202....1S",
  "body": "M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),\nJ. R. Cummings, N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), J. Tueller (GSFC),\nT. 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 downlink,\nwe report further analysis of BAT GRB 141220A (trigger #621915) (Cummings, et al.,\nGCN Circ. 17196).  The BAT ground-calculated position is RA, Dec = 195.058, 32.146\ndeg which is:\n    RA(J2000)  =  13h 00m 14.0s\n    Dec(J2000) = +32d 08' 46.4\"\nwith an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 19%.\n  \nThe mask-weighted light curve shows two peaks at about T+1 and T+3 seconds,\nwith an exponential decline noticeable out to ~T+20 seconds.  T90 (15-350 keV)\nis 7.21 +- 0.48 sec (estimated error including systematics).\n  \nThe time-averaged spectrum from T-0.91 to T+7.30 sec is best fit by a power law\nwith an exponential cutoff.  This fit gives a photon index 0.62 +- 0.38,\nand Epeak of 117.4 +- 45.1 keV (chi squared 56.50 for 56 d.o.f.).  For this\nmodel the total fluence in the 15-150 keV band is 2.6 +- 0.1 x 10^-06 erg/cm2\nand the 1-sec peak flux measured from T-0.13 sec in the 15-150 keV band is\n8.9 +- 0.7 ph/cm2/sec.  A fit to a simple power law gives a photon index\nof 1.30 +- 0.08 (chi squared 67.35 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/621915/BA/",
  "circularId": 17202,
  "createdOn": 1419094119000,
  "email": "james.r.cummings@nasa.gov",
  "subject": "GRB 141220A: Swift-BAT refined analysis",
  "submitter": "Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>",
  "eventId": "GRB 141220A"
}