{
  "bibcode": "2018GCN.23583....1L",
  "body": "A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),\nJ. R. Cummings (CPI), H. A. Krimm (NSF/USRA),\nC. B. Markwardt (GSFC), M. J. Moss (GWU),\nD. M. Palmer (LANL), T. Sakamoto (AGU),\nM. Stamatikos (OSU), T. N. Ukwatta (LANL)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-240 to T+962 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 181228A (trigger #879909)\n(Moss et al., GCN Circ. 23570).  The BAT ground-calculated position is\nRA, Dec = 49.831, 13.212 deg which is\n  RA(J2000)  =  03h 19m 19.5s\n  Dec(J2000) = +13d 12' 44.0\"\nwith an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 30%.\n\nThe mask-weighted light curve shows a multi-peaked structure. The main\nstructure starts at ~T-4 s and ends at ~T+20 s, with the highest peak\noccurs at ~ T+13 s. After the main pulse, there is another much weaker\npulse that starts at ~ T+200 s and ends at ~T+340 s. T90 (15-350 keV)\nis 257.3 +- 102.5 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T-4.0 to T+337.9 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n1.45 +- 0.06.  The fluence in the 15-150 keV band is 1.0 +- 0.03 x 10^-05 erg/cm2.\nThe 1-sec peak photon flux measured from T+13.08 sec in the 15-150 keV band\nis 9.5 +- 0.5 ph/cm2/sec.  All the quoted errors are at the 90% confidence\nlevel.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/879909/BA/",
  "circularId": 23583,
  "createdOn": 1546023374000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 181228A: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 181228A"
}