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 -29.272 sec. to 29.424 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.81702 ( -0.0739523 0.0732011 )
Norm@50keV : 3.56648E-03 ( -0.000148136 0.000147382 )
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#Fit statistic : Chi-Squared = 56.74 using 59 PHA bins.
# Reduced chi-squared = 0.9955 for 57 degrees of freedom
# Null hypothesis probability = 4.846699e-01
Photon flux (15-150 keV) in 58.7 sec: 0.494761 ( -0.019735 0.019777 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.92659e-06 ( -8.12396e-08 8.16646e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -29.272 sec. to 29.424 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.35257 ( -0.312469 0.339954 )
Epeak [keV] : 64.7031 ( -10.861 38.2856 )
Norm@50keV : 6.26371E-03 ( -0.00193866 0.00314907 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 50.09 using 59 PHA bins.
# Reduced chi-squared = 0.8944 for 56 degrees of freedom
# Null hypothesis probability = 6.971669e-01
Photon flux (15-150 keV) in 58.7 sec: 0.479949 ( -0.021935 0.021959 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.83695e-06 ( -9.98786e-08 1.0013e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 5.632 sec. to 6.632 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.52994 ( -0.154172 0.151864 )
Norm@50keV : 1.19061E-02 ( -0.00115822 0.00114868 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 52.03 using 59 PHA bins.
# Reduced chi-squared = 0.9129 for 57 degrees of freedom
# Null hypothesis probability = 6.614711e-01
Photon flux (15-150 keV) in 1 sec: 1.49869 ( -0.13715 0.13719 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.12432e-07 ( -1.19427e-08 1.20854e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 5.632 sec. to 6.632 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.715631 ( -0.662335 0.786658 )
Epeak [keV] : 72.3034 ( -17.0945 106.687 )
Norm@50keV : 3.29708E-02 ( -0.0183107 0.0544075 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 47.50 using 59 PHA bins.
# Reduced chi-squared = 0.8482 for 56 degrees of freedom
# Null hypothesis probability = 7.834271e-01
Photon flux (15-150 keV) in 1 sec: 1.45688 ( -0.14154 0.14145 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.04097e-07 ( -1.34278e-08 1.37775e-08 ) ergs/cm2
Time-resolved spectra