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 -20.460 sec. to 20.476 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.69785 ( -0.184898 0.179821 )
Norm@50keV : 1.80876E-03 ( -0.00020791 0.000204879 )
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#Fit statistic : Chi-Squared = 61.72 using 59 PHA bins.
# Reduced chi-squared = 1.083 for 57 degrees of freedom
# Null hypothesis probability = 3.113127e-01
Photon flux (15-150 keV) in 40.94 sec: 0.240053 ( -0.025011 0.025028 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.85831e-07 ( -8.22607e-08 8.34198e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -20.460 sec. to 20.476 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.19049 ( -0.624674 0.818533 )
Epeak [keV] : 73.3627 ( -23.2996 -73.3628 )
Norm@50keV : 3.40635E-03 ( -0.00172359 0.00589051 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 60.20 using 59 PHA bins.
# Reduced chi-squared = 1.075 for 56 degrees of freedom
# Null hypothesis probability = 3.263862e-01
Photon flux (15-150 keV) in 40.94 sec: 0.235405 ( -0.025871 0.025837 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.55658e-07 ( -9.06981e-08 9.27659e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.108 sec. to 1.108 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.69424 ( -0.201324 0.193459 )
Norm@50keV : 1.23190E-02 ( -0.00157485 0.00154891 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.36 using 59 PHA bins.
# Reduced chi-squared = 0.8836 for 57 degrees of freedom
# Null hypothesis probability = 7.204935e-01
Photon flux (15-150 keV) in 1 sec: 1.63289 ( -0.18783 0.18792 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.14127e-07 ( -1.52079e-08 1.54178e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.108 sec. to 1.108 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.896995 ( -0.863282 1.10424 )
Epeak [keV] : 63.6293 ( -16.2185 -63.6264 )
Norm@50keV : 3.32965E-02 ( -0.033302 0.0973985 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.05 using 59 PHA bins.
# Reduced chi-squared = 0.8579 for 56 degrees of freedom
# Null hypothesis probability = 7.662995e-01
Photon flux (15-150 keV) in 1 sec: 1.58976 ( -0.19567 0.19469 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.07137e-07 ( -1.67429e-08 1.72915e-08 ) ergs/cm2
Time-resolved spectra
