{
  "bibcode": "2019GCN.26133....1S",
  "body": "T. Sakamoto (AGU), S. D. Barthelmy (GSFC), V. D'Elia (SSDC),\nH. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), J. P. Norris (BSU), D. M. Palmer (LANL), \nM. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):\n\nUsing the data set from T-61 to T+242 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 191031D (trigger #932608)\n(D'Elia, et al., GCN Circ. 26112).  The BAT ground-calculated position is\nRA, Dec = 283.269, 47.645 deg which is \n RA(J2000)  =  18h 53m 04.5s \n Dec(J2000) = +47d 38' 40.9\" \nwith an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 37%.\n\nThe mask-weighted light curve shows a multi-peak structure from T-0.05 sec to T+0.3 sec\nwith a harder first pulse and softer second pulse.  There is no sign of extended emission.\nT90 (15-350 keV) is 0.29 +- 0.05 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T-0.03 to T+0.31 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n0.80 +- 0.15.  The fluence in the 15-150 keV band is 4.1 +- 0.4 x 10^-7 erg/cm2.\nThe 1-sec peak photon flux measured from T-0.36 sec in the 15-150 keV band\nis 4.3 +- 0.4 ph/cm2/sec.  All the quoted errors are at the 90% confidence\nlevel. \n\nThe duration and hardness of GRB 191031D place it squarely within the distribution of\nshort, hard bursts detected by BAT.   Using the 4-ms binned light curve, the spectral lag \nof the burst is 0.2 ms +- 2 ms for the 50-100 keV to 15-25 keV bands, and 0.4 ms +- 3 ms\nfor the 100-350 keV to 25-50 keV bands. These values are consistent with a short GRB.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/932608/BA/",
  "circularId": 26133,
  "createdOn": 1572635267000,
  "email": "hkrimm@nsf.gov",
  "subject": "GRB 191031D: Swift-BAT refined analysis",
  "submitter": "Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>",
  "eventId": "GRB 191031D"
}