{
  "bibcode": "2018GCN.23155....1C",
  "body": "J. R. Cummings (CPI), S. D. Barthelmy (GSFC),\nH. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), F. E. Marshall (NASA/GSFC),\nD. M. Palmer (LANL), T. Sakamoto (AGU),\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 180818B (trigger #853882)\n(Marshall et al., GCN Circ. 23149).  The BAT ground-calculated position is\nRA, Dec = 104.227, 39.310 deg which is\n  RA(J2000)  =  06h 56m 54.5s\n  Dec(J2000) = +39d 18' 35.1\"\nwith an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 89%.\n\nThe mask-weighted light curve shows two pulses. The first pulse starts at\nat ~T-100 s, peaks at ~T-80 s, and ends at ~T-50 s. The second pulse starts\nat ~T+10 s, peaks at ~T+30 s, and ends at ~T+60 s. T90 (15-350 keV) is\n134.4 +- 9.8 sec (estimated error including systematics). However, note that\nthe burst came into the BAT FOV at ~T-128 s, and thus there might be additional\nburst emission beforehand.\n\nThe time-averaged spectrum from T-93.58 to T+62.74 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n1.77 +- 0.12.  The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-6 erg/cm2.\nThe 1-sec peak photon flux measured from T-82.11 sec in the 15-150 keV band\nis 1.2 +- 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/853882/BA/",
  "circularId": 23155,
  "createdOn": 1534640433000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 180818B: Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 180818B"
}