{
  "bibcode": "2018GCN.23082....1S",
  "body": "T. Sakamoto (AGU), S. D. Barthelmy (GSFC),\nJ. R. Cummings (CPI), P. D'Avanzo (INAF-OAB),\nH. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), J. P. Norris (BSU),\nD. M. Palmer (LANL), M. Stamatikos (OSU),\nT. N. Ukwatta (LANL) (i.e. the Swift-BAT team):\n\nUsing the data set from T-240 to T+962 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 180805B (trigger #851855)\n(D'Avanzo et al., GCN Circ. 23076).  The BAT ground-calculated position is\nRA, Dec = 25.877, -17.475 deg which is\n  RA(J2000)  =  01h 43m 30.6s\n  Dec(J2000) = -17d 28' 29.3\"\nwith an uncertainty of 3.1 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 67%.\n\nThe mask-weighted light curve show a short pulse that starts from ~T-0.1 s,\npeaks at ~T+0.1 s, and ends at ~T+0.7 s. The short pulse is followed by\nsome weak emission that lasts until ~ T+130 s. T90 (15-350 keV) is\n122.5 +- 18.3 sec (estimated error including systematics).\n\nThe time-averaged spectrum from T-0.10 to T+127.46 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n1.13 +- 0.29.  The fluence in the 15-150 keV band is 9.6 +- 1.7 x 10^-7 erg/cm2.\nThe 1-sec peak photon flux measured from T-0.11 sec in the 15-150 keV band\nis 1.7 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence\nlevel.\n\nThe structure of the burst shows similarity to those of short GRBs with\nextended emission. We thus perform further analysis on the short spike and the\ntail emission.\n\nThe spectrum of the short pulse from T-0.001 to T+0.712 sec can be fitted by\na simple power-law model with power-law index of 0.66 +- 0.20 and\nfluence (15-150 keV) of 1.7 +- 0.2 x 10^-7 erg/cm2. The spectrum of the\nextended emission from T+0.712 to T+126.532 sec is best fit by a simple power-law\nmodel, with power-law index of 1.16 +- 0.39 and fluence (15-150 keV) of\n6.8 +- 1.6 x 10^-7 erg/cm2. These values are consistent with those of short GRBs\nwith extended emission (Lien & Sakamoto et al. 2016).\n\nThe lag analysis does not produce a well-constrained value due to the weakness\nof the short pulse.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/851855/BA/",
  "circularId": 23082,
  "createdOn": 1533520836000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 180805B: Swift-BAT refined analysis (short GRB with extended emission)",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 180805B"
}