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 -0.220 sec. to 1.844 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.41801 ( -0.22981 0.229011 )
Norm@50keV : 2.00056E-02 ( -0.00266355 0.00265496 )
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#Fit statistic : Chi-Squared 45.64 using 59 bins.
Reduced chi-squared = 0.800702
# Null hypothesis probability of 8.60e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 2.064 sec: 2.44650 ( -0.33155 0.33247 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.97595e-07 ( -5.79303e-08 5.8379e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.220 sec. to 1.844 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.27291 ( -1.36152 0.998392 )
Epeak [keV] : 260.707 ( -266.328 -266.328 )
Norm@50keV : 2.35518E-02 ( -0.0194291 0.0458727 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 45.57 using 59 bins.
Reduced chi-squared = 0.81375
# Null hypothesis probability of 8.39e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 2.064 sec: 2.43319 ( -0.3423 0.33308 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.94511e-07 ( -6.14989e-08 5.96395e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.424 sec. to 1.424 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.33719 ( -0.260136 0.257948 )
Norm@50keV : 2.41030E-02 ( -0.0039001 0.00389427 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 50.68 using 59 bins.
Reduced chi-squared = 0.889123
# Null hypothesis probability of 7.10e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 2.89622 ( -0.48126 0.48291 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.36118e-07 ( -4.12009e-08 4.15015e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.424 sec. to 1.424 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.0513541 ( -1.18114 1.66889 )
Epeak [keV] : 84.7899 ( -19.6206 135.047 )
Norm@50keV : 9.98790E-02 ( -0.0998791 0.351531 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 46.50 using 59 bins.
Reduced chi-squared = 0.830357
# Null hypothesis probability of 8.13e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 2.74153 ( -0.51078 0.50578 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.49415e-08 ( -4.40135e-08 1.71666e-08 ) ergs/cm2
Time-resolved spectra
