{
  "bibcode": "2018GCN.22658....1P",
  "body": "D. M. Palmer (LANL), S. D. Barthelmy (GSFC),\nJ. R. Cummings (CPI), V. D'Elia (ASDC),\nH. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), J. P. Norris (BSU),\nT. Sakamoto (AGU), M. 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 180418A (trigger #826428)\n(D'Elia et al., GCN Circ. 22646).  The BAT ground-calculated position is\nRA, Dec = 170.132, 24.925 deg which is\n  RA(J2000)  =  11h 20m 31.6s\n  Dec(J2000) = +24d 55' 28.9\"\nwith an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 100%.\n\nThe mask-weighted light curve shows a single FRED-like pulse that starts\nat ~T0, peaks at ~T+0.4 s, and ends at ~T+3.5 s. T90 (15-350 keV)\nis 2.29 +- 0.83 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T+0.10 to T+3.50 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n1.44 +- 0.12.  The fluence in the 15-150 keV band is 3.2 +- 0.2 x 10^-7 erg/cm2.\nThe 1-sec peak photon flux measured from T+0.23 sec in the 15-150 keV band\nis 3.0 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence\nlevel.\n\nThe duration and hardness of this burst show it to be intermediate between the\nshort and long burst populations.\n\nUsing a 16-ms binned light curve, the lag analysis finds a lag of 0.1000 +/- 0.026 s\nfor the 100-350 keV to 25-50 keV band, and 0.088 +/- 0.026 s for the 50-100 keV\nto 15-25 keV band. These values are also intermediate between canonical short and\nlong GRBs.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/826428/BA/",
  "circularId": 22658,
  "createdOn": 1524089369000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 180418A: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 180418A"
}