{
  "bibcode": "2021GCN.30580....1S",
  "body": "M. Stamatikos (OSU), S. D. Barthelmy (GSFC),\nH. A. Krimm (NSF), S. Laha (GSFC/UMBC),\nA. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),\nD. M. Palmer (LANL), T. Sakamoto (AGU),\nE. Troja (NASA/GSFC/UMCP) T. N. Ukwatta (LANL)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-239 to T+409 sec from the recent telemetry\ndownlink, we report further analysis of BAT GRB 210731A (trigger #1062336)\n(Troja et al., GCN Circ. 30568).  The BAT ground-calculated position is\nRA, Dec = 300.311, -28.056 deg which is\n   RA(J2000)  =  20h 01m 14.5s\n   Dec(J2000) = -28d 03' 20.0\"\nwith an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 39%.\n\nThe mask-weighted light curve shows a single-pulse structure that\nstarts at ~T-1 s, peaks at ~T+11 s, and ends at ~T+30 s.\nT90 (15-350 keV) is 22.51 +- 2.79 sec (estimated error\nincluding systematics).\n\nThe time-averaged spectrum from T-0.78 to T+25.50 sec is best fit\nby a power law with an exponential cutoff.  This fit gives a photon\nindex -0.25 +- 0.59, and Epeak of 106.5 +- 26.8 keV (chi squared\n50.28 for 56 d.o.f.).  For this model the total fluence in the 15-150 keV\nband is 2.2 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured\nfrom T+11.28 sec in the 15-150 keV band is 1.6 +- 0.3 ph/cm2/sec.\nA fit to a simple power law gives a photon index of 1.01 +- 0.11\n(chi squared 67.96 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/1062336/BA/",
  "circularId": 30580,
  "createdOn": 1627852367000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 210731A: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 210731A"
}