{
  "bibcode": "2020GCN.27273....1M",
  "body": "C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),\nJ. R. Cummings (CPI), H. A. Krimm (NSF),\nS. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),\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+297 sec from the recent telemetry\ndownlink,\nwe report further analysis of BAT GRB 200228B (trigger #958733)\n(Laha et al., GCN Circ. 27254).  The BAT ground-calculated position is\nRA, Dec = 252.007, 16.964 deg which is\n   RA(J2000)  =  16h 48m 01.8s\n   Dec(J2000) = +16d 57' 50.3\"\nwith an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 31%.\n\nThe mask-weighted light curve shows a weak pulse that starts at ~T-1 s,\npeaks at ~T+2 s, and ends at ~T+7 s. T90 (15-350 keV) is 7.37 +- 1.58 sec\n(estimated error including systematics).\n\nThe time-averaged spectrum from T-0.84 to T+6.97 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n2.27 +- 0.36.  The fluence in the 15-150 keV band is 3.0 +- 0.6 x 10^-7\nerg/cm2.\nThe 1-sec peak photon flux measured from T+1.32 sec in the 15-150 keV band\nis 1.0 +- 0.4 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/958733/BA/",
  "circularId": 27273,
  "createdOn": 1583020173000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 200228B: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 200228B"
}