{
  "bibcode": "2018GCN.22821....1U",
  "body": "T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),\nJ. R. Cummings (CPI), P. A. Evans (U Leicester),\nH. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), D. M. Palmer (LANL),\nT. Sakamoto (AGU), M. Stamatikos (OSU)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-179 to T+843 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 180620B (trigger #843211)\n(Evans et al., GCN Circ. 22807).  The BAT ground-calculated position is\nRA, Dec = 357.514, -57.954 deg which is\n  RA(J2000)  =  23h 50m 03.3s\n  Dec(J2000) = -57d 57' 13.5\"\nwith an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 78%.\n\nThe mask-weighted light curve shows a multi-peaked structure that starts\nat ~T-160 s and ends at ~T+160 s. The three main peaks occur at ~T0, ~T+40 s,\nand ~T+100 s, respectively. Note that because the event data are only available\nfrom ~T-180 s, there might be additional burst emission before the available\nevent data range. T90 (15-350 keV) is 198.8 +- 27.4 sec (estimated\nerror including systematics).\n\nThe time-averaged spectrum from T-159.376 to T+162.428 sec is best fit by a power law\nwith an exponential cutoff.  This fit gives a photon index 1.30 +- 0.20,\nand Epeak of 123.9 +- 68.3 keV (chi squared 58.09 for 56 d.o.f.).  For this\nmodel the total fluence in the 15-150 keV band is 1.0 +- 0.03 x 10^-5 erg/cm2\nand the 1-sec peak flux measured from T-0.33 sec in the 15-150 keV band is\n3.6 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index\nof 1.60 +- 0.05 (chi squared 65.76 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/843211/BA/",
  "circularId": 22821,
  "createdOn": 1529628320000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 180620B: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 180620B"
}