{
  "bibcode": "2014GCN.16306....1U",
  "body": "T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),\nJ. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),\nA. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB),\nD. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),\nJ. Tueller (GSFC) (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 140518A (trigger #599287)\n(Melandri, et al., GCN Circ. 16298).  The BAT ground-calculated position is\nRA, Dec = 227.231, 42.396 deg which is\n  RA(J2000)  =  15h 08m 55.3s\n  Dec(J2000) = +42d 23' 44.2\"\nwith an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 89%.\n\nThe mask-weighted light curve shows multiple peaks with roughly three main pulse\nstructures. The first main pulse starts at ~T-4 s and ends at ~T+8 s. The second main\npulse starts at ~T+38 s, followed immediately by the third main pulse structure that\nstarts at ~T+48 s and ends at ~T+61 s. Additionally, each of these main pulse structure\ncontains several  sub-pulses. T90 (15-350 keV) is 60.5 +- 2.4 sec (estimated error\nincluding systematics).\n\nThe time-averaged spectrum from T-4.1 to T+60.0 sec is best fit by a power law\nwith an exponential cutoff.  This fit gives a photon index 0.92 +- 0.61,\nand Epeak of 43.9 +- 7.6 keV (chi squared 54.15 for 56 d.o.f.).  For this\nmodel the total fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2\nand the 1-sec peak flux measured from T+41.94 sec in the 15-150 keV band is\n1.0 +- 0.1 ph/cm2/sec.  A fit to a simple power law gives a photon index\nof 1.97 +- 0.13 (chi squared 65.02 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/599287/BA/",
  "circularId": 16306,
  "createdOn": 1400459272000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 140518A, Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 140518A"
}