{
  "bibcode": "2009GCN..9955....1S",
  "body": "M. Stamatikos (OSU), S. D. Barthelmy (GSFC),\nW. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),\nE. E. Fenimore (LANL), N. Gehrels (GSFC), D. Grupe (PSU),\nH. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),\nD. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),\nG. Sato (ISAS), J. Tueller (GSFC), T. N. Ukwatta (GWU)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-239 to T+963 sec from the recent telemetry\ndownlink, we report further analysis of BAT GRB 090927 (trigger #370846)\n(Grupe, et al., GCN Circ. 9945).  The BAT ground-calculated position is\nRA, Dec = 343.929, -70.973 deg which is\n    RA(J2000)  =  22h 55m 42.9s\n    Dec(J2000) = -70d 58' 24.2\"\nwith an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 55%.\n\nThe mask-weighted light curve shows a single irregular peak with an\noverall roughly FRED shape.  T90 (15-350 keV) is 2.2 +- 0.4 sec \n(estimated error including systematics).\n\nThe time-averaged spectrum from T+0.0 to T+2.4 sec is best fit by a\nsimple power-law model.  The power law index of the time-averaged\nspectrum is 1.80 +- 0.20.  The fluence in the 15-150 keV band is\n2.0 +- 0.3 x 10^-07 erg/cm2.  The 1-sec peak photon flux measured from\nT-0.01 sec in the 15-150 keV band is 2.0 +- 0.2 ph/cm2/sec.  All the\nquoted errors are at the 90% confidence level.\n\nThe classification of this burst as short or long is not clear.  The\nburst appears to have significant lag between energy bands, and\nmoreover is not particularly hard.  We expect to perform a more\nquantitative lag analysis and report the results in an additional\ncircular.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/370846/BA/",
  "circularId": 9955,
  "createdOn": 1254080162000,
  "email": "james.r.cummings@nasa.gov",
  "subject": "GRB 090927, Swift-BAT refined analysis of the possibly short burst",
  "submitter": "Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>",
  "eventId": "GRB 090927"
}