Notes:
- 1) The fitting includes the systematic errors.
- 2) When the burst includes telescope slew time periods, the fitting uses an average response file made from multiple 5-s response files through out the slew time plus single time preiod for the non-slew times, and weighted by the total counts in the corresponding time period using addrmf. An average response file is needed becuase a spectral fit using the pre-slew DRM will introduce some errors in both a spectral shape and a normalization if the PHA file contains a lot of the slew/post-slew time interval.
- 3) For fits to more complicated models (e.g. a power-law over a cutoff power-law), the BAT team has decided to require a chi-square improvement of more than 6 for each extra dof.
Time averaged spectrum fit using the average DRM
Power-law model
Time interval is from -104.996 sec. to 109.556 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.51673 ( -0.0845144 0.0843159 )
Norm@50keV : 1.79826E-03 ( -8.30342e-05 8.27559e-05 )
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#Fit statistic : Chi-Squared = 43.81 using 59 PHA bins.
# Reduced chi-squared = 0.7686 for 57 degrees of freedom
# Null hypothesis probability = 9.000920e-01
Photon flux (15-150 keV) in 214.6 sec: 0.225524 ( -0.010597 0.010615 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.65157e-06 ( -1.83884e-07 1.84882e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -104.996 sec. to 109.556 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.39106 ( -0.169451 0.325186 )
Epeak [keV] : 243.417 ( -243.44 -243.44 )
Norm@50keV : 2.07822E-03 ( -0.000350043 0.000913732 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 43.32 using 59 PHA bins.
# Reduced chi-squared = 0.7736 for 56 degrees of freedom
# Null hypothesis probability = 8.921391e-01
Photon flux (15-150 keV) in 214.6 sec: 0.223829 ( -0.011341 0.011323 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.61028e-06 ( -2.09882e-07 2.08457e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 8.240 sec. to 9.240 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.39868 ( -0.268493 0.267021 )
Norm@50keV : 8.39811E-03 ( -0.00135394 0.00134742 )
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#Fit statistic : Chi-Squared = 37.57 using 59 PHA bins.
# Reduced chi-squared = 0.6590 for 57 degrees of freedom
# Null hypothesis probability = 9.781528e-01
Photon flux (15-150 keV) in 1 sec: 1.02244 ( -0.164236 0.16457 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.11802e-08 ( -1.43889e-08 1.46142e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 8.240 sec. to 9.240 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.397876 ( -1.09961 1.55835 )
Epeak [keV] : 80.1256 ( -22.1651 -80.1256 )
Norm@50keV : 2.67223E-02 ( -0.0267223 0.124731 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 35.44 using 59 PHA bins.
# Reduced chi-squared = 0.6329 for 56 degrees of freedom
# Null hypothesis probability = 9.855320e-01
Photon flux (15-150 keV) in 1 sec: 0.980547 ( -0.172899 0.172283 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.53894e-08 ( -1.554e-08 1.6123e-08 ) ergs/cm2
Time-resolved spectra