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 -1.760 sec. to 87.244 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.51633 ( -0.056395 0.0562688 )
Norm@50keV : 9.57661E-03 ( -0.000285061 0.000284991 )
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#Fit statistic : Chi-Squared = 63.20 using 59 PHA bins.
# Reduced chi-squared = 1.109 for 57 degrees of freedom
# Null hypothesis probability = 2.668113e-01
Photon flux (15-150 keV) in 89 sec: 1.20089 ( -0.03876 0.03887 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.06547e-06 ( -2.56032e-07 2.5657e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.760 sec. to 87.244 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.24266 ( -0.225752 0.237746 )
Epeak [keV] : 149.468 ( -45.3865 378.216 )
Norm@50keV : 1.28370E-02 ( -0.00269383 0.00361599 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.89 using 59 PHA bins.
# Reduced chi-squared = 1.052 for 56 degrees of freedom
# Null hypothesis probability = 3.703100e-01
Photon flux (15-150 keV) in 89 sec: 1.17729 ( -0.04294 0.04315 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.91061e-06 ( -2.87191e-07 2.86293e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 44.460 sec. to 45.460 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.15815 ( -0.137867 0.138645 )
Norm@50keV : 3.80065E-02 ( -0.0031388 0.0031382 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 68.85 using 59 PHA bins.
# Reduced chi-squared = 1.208 for 57 degrees of freedom
# Null hypothesis probability = 1.351358e-01
Photon flux (15-150 keV) in 1 sec: 4.43670 ( -0.37614 0.37662 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.90346e-07 ( -3.53692e-08 3.55661e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 44.460 sec. to 45.460 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.472784 ( -0.5926 0.684067 )
Epeak [keV] : 126.338 ( -36.9441 367.447 )
Norm@50keV : 7.77472E-02 ( -0.035265 0.0757852 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 64.90 using 59 PHA bins.
# Reduced chi-squared = 1.159 for 56 degrees of freedom
# Null hypothesis probability = 1.941445e-01
Photon flux (15-150 keV) in 1 sec: 4.33145 ( -0.38818 0.38781 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.80487e-07 ( -3.72137e-08 3.70837e-08 ) ergs/cm2
Time-resolved spectra
