{
  "bibcode": "2012GCN.13614....1S",
  "body": "T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC),\nW. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC),\nE. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),\nC. Markwardt (GSFC/UMD), D. Palmer (LANL), G. Sato (ISAS),\nM. Stamatikos (OSU), J. Tueller (GSFC), and T. Ukwatta (MSU)\non behalf of the Swift-BAT team,\n\nV. Pal'shin, S. Golenetskii, R.Aptekar, E. Mazets, D. Frederiks, and\nT. Cline on behalf of the Konus-Wind team,\nreport:\n\nThe short GRB 120804A (Swift/BAT trigger #529686: Lien et al., GCN Circ.\n13573, Baumgartner et al. GCN Circ. 13581) triggered Konus-Wind at\nT0=3255.749 s UT (00:54:15.749), but since the incident angle on the\ntriggered detector was 99.2 deg (i.e. the burst accidentally triggered\nthe S2 detector which observes the northern ecliptic hemisphere,\nalthough the burst came from the southern ecliptic hemisphere: b = -9.2\ndeg) the standard analysis of the Konus-Wind spectral data is impossible.\n\nTo derive the broad-band spectral parameters of this burst, we performed\njoint spectral analysis of the Swift/BAT data and the Konus-Wind\n3-channel spectral data (obtained in the waiting mode from the detector\nS1), which covers the energy range from 24 keV to 1.4 MeV.\n\nThe time intervals of the spectral data are chosen for the Konus-Wind\nfrom T0(BAT)-0.916 s to T0(BAT)+2.028 s (single KW bin which comprises\nthe burst) and for the Swift/BAT from T0(BAT)-0.16 s to T0(BAT)+0.83 s\n(that is the BAT T100 interval), where T0(BAT) is the trigger time of\nBAT at 00:54:14.18 UTC. The energy ranges which we used in the joint\nspectral analysis are 24-1400 keV and 14-150 keV for the Konus-Wind and\nthe Swift/BAT respectively.  The spectral data of the two instruments \nare fitted with the spectral model multiplied by a constant factor to \ntake into account the systematic effective area uncertainties in the \nresponse matrices of each instrument and the difference in the chosen \nintervals.\n\nThe spectrum is well fitted with a power-law with exponential cutoff\nmodel: dN/dE ~ E^{alpha}*exp(-(2+alpha)*E/Epeak). No systematic residual\nfrom the best fit model is seen in the spectral data of each instrument.\nThe best fit spectral parameters are: alpha = -0.89 (-0.28, +0.24) and\nEpeak = 135 (-29, +66) keV (chi2/dof = 56/58).\n\nThe energy fluence and 16-ms peak flux in the 15-1000 keV band\nare 1.45 (-0.31,+0.30) x 10^-6 erg/cm2 and (6.0 �� 2.7) x 10^-6 erg/cm2/s \nrespectively.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB120804_T03255/\n\nAll the quoted errors are at the 90% confidence level.",
  "circularId": 13614,
  "createdOn": 1344541736000,
  "email": "val@mail.ioffe.ru",
  "subject": "GRB 120804A: Konus-Wind and Swift/BAT joint spectral analysis",
  "submitter": "Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>",
  "eventId": "GRB 120804A"
}