{
  "bibcode": "2009GCN..9337....1U",
  "body": "T. N. Ukwatta (GWU) S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),\nJ. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),\nE. A. Hoversten (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),\nD. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),\nG. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)\n(i.e. the Swift-BAT team):\n \nUsing the data set from T-60 to T+243 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 090510 (trigger #351588)\n(Hoversten, et al., GCN Circ. 9331).  The BAT ground-calculated position is\nRA, Dec = 333.552, -26.598 deg, which is \n   RA(J2000)  =  22h 14m 12.6s \n   Dec(J2000) = -26d 35' 51.1\" \nwith an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 16%.\n \nThe mask-weighted light curve shows a small precursor peak at ~T-0.54 sec\n(width ~ 30 msec).  Then the main peak starts at ~T-0.05 sec, peaks at T+0.04 sec\nwith a width of ~50 msec.  Then come two smaller peaks at T+0.24 and T+0.32 sec,\neach about 40 msec in width.  At the 3-sigma level, there is the possibility\nof low-level emission between T+110 sec to ~T+170 sec.  T90 (15-350 keV)\nis 0.3 +- 0.1 sec (estimated error including systematics).\n \nThe time-averaged spectrum from T+0.0 to T+0.4 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n0.98 +- 0.20.  The fluence in the 15-150 keV band is 3.4 +- 0.4 x 10^-7 erg/cm2.\nThe 1-sec peak photon flux measured from T-0.30 sec in the 15-150 keV band\nis 9.7 +- 1.1 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/351588/BA/",
  "circularId": 9337,
  "createdOn": 1241935720000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 090510: Swift-BAT refined analysis",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 090510"
}