{
  "bibcode": "2017GCN.21912....1S",
  "body": "T. Sakamoto (AGU), S. D. Barthelmy (GSFC),\nJ. R. Cummings (CPI), A. D'Ai (INAF-IASFPA)\nH. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), D. M. Palmer (LANL),\nM. Stamatikos (OSU), T. N. Ukwatta (LANL)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-239 to T+963 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 170921A (trigger #773509)\n(D'Ai et al., GCN Circ. 21901).  The BAT ground-calculated position is\nRA, Dec = 26.840, 30.880 deg which is\n  RA(J2000)  =  01h 47m 21.6s\n  Dec(J2000) = +30d 52' 47.1\"\nwith an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 86%.\n\nThe mask-weighted light curve shows a single-peaked structure that starts at\n~T-22 s, peaks at ~T+3 s, and ends at ~T+13 s. T90 (15-350 keV) is\n28.9 +- 6.0 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T-21.82 to T+13.00 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n1.76 +- 0.17.  The fluence in the 15-150 keV band is 6.7 +- 0.8 x 10^-7 erg/cm2.\nThe 1-sec peak photon flux measured from T+2.74 sec in the 15-150 keV band\nis 0.8 +- 0.2 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/773509/BA/",
  "circularId": 21912,
  "createdOn": 1506090435000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 170921A: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 170921A"
}