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 -0.216 sec. to 7.936 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.80652 ( -0.0926036 0.091441 )
Norm@50keV : 2.27983E-02 ( -0.0012568 0.00125303 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 58.29 using 59 bins.
Reduced chi-squared = 1.02263
# Null hypothesis probability of 4.28e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 8.152 sec: 3.14970 ( -0.18106 0.18168 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.71086e-06 ( -9.54452e-08 9.56654e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.216 sec. to 7.936 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.06206 ( -0.408281 0.447159 )
Epeak [keV] : 63.9075 ( -8.72115 19.2608 )
Norm@50keV : 5.34469E-02 ( -0.0196012 0.0349084 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 47.98 using 59 bins.
Reduced chi-squared = 0.856786
# Null hypothesis probability of 7.68e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 8.152 sec: 3.02626 ( -0.19139 0.19221 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.64329e-06 ( -1.02956e-07 1.02952e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 1.636 sec. to 2.636 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.86106 ( -0.149026 0.143873 )
Norm@50keV : 3.88250E-02 ( -0.00388363 0.00385805 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 68.54 using 59 bins.
Reduced chi-squared = 1.20246
# Null hypothesis probability of 1.41e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 5.48232 ( -0.54253 0.54395 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.57001e-07 ( -3.56645e-08 3.57524e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.636 sec. to 2.636 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.226801 ( -0.781635 0.982822 )
Epeak [keV] : 53.7711 ( -6.67283 9.8958 )
Norm@50keV : 0.265552 ( -0.15865 0.593599 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 53.32 using 59 bins.
Reduced chi-squared = 0.952143
# Null hypothesis probability of 5.77e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 5.22752 ( -0.55235 0.55465 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.40706e-07 ( -3.76869e-08 3.77366e-08 ) ergs/cm2
Time-resolved spectra
