{
  "bibcode": "2011GCN.12477....1S",
  "body": "T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), \nJ. Norris (BSU), T. N. Ukwatta (MSU)\n\nWe report the spectral lag analysis for GRB 111020A (GCN Circ. 12460) \nbased on the BAT data.  Using 64 ms binned light curves, the spectral \nlag for 15-25 keV to 50-100 keV is 124 +36/-38 msec.  This significant \nlag is due to a broader pulse in the 15-25 keV band comparing to that \nin the 50-100 keV band which indicates the strong pulse evolution from \nhard to soft.  Although the burst duration itself is short (T90 = 400 ms; \nGCN Circ. 12464), this positive lag argues against a \"short\" classification.  \n\nHowever, there is a possibility that the broader pulse seen in the \n15-25 keV band is composed from two pulses instead of a single pulse.  \nIf this is the case, the lag result above could be confused by \ncross-correlating the 2nd pulse in the 15-25 keV and the 1st pulse \nin the 50-100 keV band.  Due to the limiting signal-to-noise in the \nlight curve data, it is not possible to claim whether the broad pulse \nin the 15-25 keV has two pulses or just a single pulse.  \n\nGive the large non-zero lag and the possible double peak interpretation\nthat could cause a false lag, we think it equally like that this burst \nis short or long. \n\n[GCN OPS NOTE(24oct11): Per author's request, the T90 value typo\nwas corrected to 400 ms.]",
  "circularId": 12477,
  "createdOn": 1319315156000,
  "email": "takanori@milkyway.gsfc.nasa.gov",
  "subject": "GRB 111020A Spectral lag analysis",
  "submitter": "Takanori Sakamoto at NASA/GSFC  <takanori@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 111020A"
}