{
  "bibcode": "2009GCN..9231....1S",
  "body": "T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),\nJ. K. Cannizzo (NASA/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL),\nN. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),\nD. M. Palmer (LANL), A. M. Parsons (GSFC), G. Sato (ISAS),\nM. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)\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 090424 (trigger #350311)\n(Cannizzo, et al., GCN Circ. 9223).  The BAT ground-calculated position is\nRA, Dec = 189.531, 16.829 deg which is \n   RA(J2000)  =  12h 38m 07.4s \n   Dec(J2000) = +16d 49' 45.9\" \nwith an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 12%.\n \nThe mask-weighted light curve shows several overlapping bright peaks\nstarting at about T-2sec and ending at about T+5 sec.  There are 3 much\nweaker, and broader, peaks at T+7, +15, and +50 sec.  The emission returns\nto background at around T+150 sec.  T90 (15-350 keV) is 48 +- 3 sec\n(estimated error including systematics).\n \nThe time-averaged spectrum from T-0.7 to T+103.2 sec is best fit by a power law\nwith an exponential cutoff.  This fit gives a photon index 1.19 +- 0.15, \nand Epeak of 108.6 +- 20.3 keV (chi squared 45.8 for 56 d.o.f.).  For this\nmodel the total fluence in the 15-150 keV band is 2.1 +- 0.0 x 10^-5 erg/cm2\nand the 1-sec peak flux measured from T-0.10 sec in the 15-150 keV band is\n71.0 +- 2.0 ph/cm2/sec.  A fit to a simple power law gives a photon index\nof 1.62 +- 0.03 (chi squared 72.0 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/350311/BA/",
  "circularId": 9231,
  "createdOn": 1240600850000,
  "email": "scott@lheamail.gsfc.nasa.gov",
  "subject": "GRB 090424: Swift-BAT refined analysis",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>",
  "eventId": "GRB 090424"
}