{
  "bibcode": "2009GCN..9272....1U",
  "body": "T. N. Ukwatta (GWU/GSFC), N. Gehrels (GSFC), H. A. Krimm\n(CRESST/GSFC/USRA), T. Sakamoto (GSFC/UMBC),\nS. D. Barthelmy (GSFC), M. Stamatikos (GSFC/ORAU)\n(for the Swift-BAT team):\n\nFor GRB 090426 (Cummings et al GCN 9254), the spectral lag analysis\nof the data from T-1 sec to T+2 sec yields a lag of -6 +/- 45 msec\nfor the 25-50 to 50-100 keV bands using light curve binnings of\n16, 32 and 64 msec. With redshift of 2.609 (Levesque et al GCN 9264)\nthis lag value transforms to 1.7 +/- 12.5 ms in the GRB\nrest frame. The lag is consistent with zero but has relatively large\nuncertainty.\n\nFurthermore, the observed T90 (1.2 +/- 0.3 sec; Swift/BAT 15-350 keV,\nSato et al., GCN 9263) and rest frame T90 (0.33 +/- 0.08 sec)\nvalues suggest a short-hard burst. However, the spectral fit\nto the BAT data (Sato et al., GCN 9263) indicates a relatively\nsoft spectrum (a power-law fit to the spectrum gives index\nof 1.93 +/- 0.22).\n\nIn summary, the observed and rest frame T90 values for GRB 090426\npoint strongly toward a short-hard burst classification.\nThe spectral lag is consistent with zero, and the spectrum is\nmarginally softer than typical for a short-hard burst.\nOur conclusion is that this burst could be either short or long,\nbut the BAT data leads toward a classification as short.",
  "circularId": 9272,
  "createdOn": 1240865027000,
  "email": "hans.krimm@nasa.gov",
  "subject": "GRB 090426: Swift/BAT spectral lag results",
  "submitter": "Hans Krimm at NASA-GSFC  <hans.krimm@nasa.gov>",
  "eventId": "GRB 090426"
}