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 -0.188 sec. to 48.360 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.55954 ( -0.152256 0.150027 )
Norm@50keV : 2.39245E-03 ( -0.000217347 0.000215606 )
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#Fit statistic : Chi-Squared = 56.23 using 59 PHA bins.
# Reduced chi-squared = 0.9865 for 57 degrees of freedom
# Null hypothesis probability = 5.038432e-01
Photon flux (15-150 keV) in 48.55 sec: 0.303722 ( -0.026305 0.026326 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.09217e-06 ( -1.07613e-07 1.08962e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.188 sec. to 48.360 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.0778 ( -0.542958 0.66367 )
Epeak [keV] : 92.1420 ( -30.557 -92.142 )
Norm@50keV : 4.26522E-03 ( -0.0019781 0.00501958 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 54.22 using 59 PHA bins.
# Reduced chi-squared = 0.9682 for 56 degrees of freedom
# Null hypothesis probability = 5.425011e-01
Photon flux (15-150 keV) in 48.55 sec: 0.297262 ( -0.027471 0.027433 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.04758e-06 ( -1.19815e-07 1.2108e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from -0.028 sec. to 0.972 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.28986 ( -0.142522 0.143498 )
Norm@50keV : 2.68031E-02 ( -0.00228193 0.00227777 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.77 using 59 PHA bins.
# Reduced chi-squared = 0.7855 for 57 degrees of freedom
# Null hypothesis probability = 8.800549e-01
Photon flux (15-150 keV) in 1 sec: 3.19183 ( -0.27491 0.27512 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.65552e-07 ( -2.52154e-08 2.54192e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.028 sec. to 0.972 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.09503 ( -0.269914 0.63672 )
Epeak [keV] : 233.623 ( -234.033 -234.033 )
Norm@50keV : 3.37228E-02 ( -0.00891042 0.0364538 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.44 using 59 PHA bins.
# Reduced chi-squared = 0.7936 for 56 degrees of freedom
# Null hypothesis probability = 8.672707e-01
Photon flux (15-150 keV) in 1 sec: 3.17332 ( -0.2809 0.28031 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.61674e-07 ( -2.83067e-08 2.76737e-08 ) ergs/cm2
Time-resolved spectra
