{
  "bibcode": "2015GCN.18196....1S",
  "body": "M. Stamatikos (OSU), S. D. Barthelmy (GSFC),  J. R. Cummings (GSFC/UMBC),\nN. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),\nC. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),\nE. Troja (NASA/GSFC/UMCP), T. N. Ukwatta (LANL)\n(i.e. the Swift-BAT team):\n\nUsing the data set from T-239 to T+963 sec from the recent telemetry downlink,\nwe report further analysis of BAT GRB 150821A (trigger #652847)\n(Troja, et al., GCN Circ. 18186).  The BAT ground-calculated position is\nRA, Dec = 341.913, -57.883 deg which is\n  RA(J2000)  =  22h 47m 39.0s\n  Dec(J2000) = -57d -52' -58.7\"\nwith an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).\nThe partial coding was 1.5%.\n\nDue to the low partial coding fraction of this burst, the light curves and\nburst durations are created using the special DETECTION mask aperture.\nHowever, the spectral analysis are done using the default FLUX aperture\nfor more accurate results, and thus the spectral analysis is only available\nafter T0+174.24 s, when the burst came into the BAT calibrated field of view.\nNote that the interval used for the spectral analysis included < 1% of the\ntotal fluence.\n\nThe  mask-weighted light curve starts at ~T0+20 s and contains several\noverlapping pulses. The main structure ends at ~T0+70 s, with a long-lasting\ntail until ~T0+330 s. T90 (15-350 keV) is 172.1 +- 99.0 sec (estimated error\nincluding systematics).\n\nThe time-averaged spectrum from T+174.2 to T+330.7 sec is best fit by a simple\npower-law model.  The power law index of the time-averaged spectrum is\n2.10 +- 0.37.  The fluence in the 15-150 keV band is 7.9 +- 1.9 x 10^-7 erg/cm2.\nThe 1-s peak spectral analysis is unavailable because the 1-s peak duration\nhappens before the burst came into the BAT calibrated field of view.\nAll the quoted errors are at the 90% confidence level.\n\nThe results of the batgrbproduct analysis are available at\nhttp://gcn.gsfc.nasa.gov/notices_s/652847/BA/",
  "circularId": 18196,
  "createdOn": 1440257570000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "GRB 150821A, Swift-BAT refined analysis",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "GRB 150821A"
}