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 -0.244 sec. to 24.156 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.82529 ( -0.31229 0.298745 )
Norm@50keV : 1.30289E-03 ( -0.000230868 0.000222634 )
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#Fit statistic : Chi-Squared = 44.37 using 59 PHA bins.
# Reduced chi-squared = 0.7785 for 57 degrees of freedom
# Null hypothesis probability = 8.887101e-01
Photon flux (15-150 keV) in 24.4 sec: 0.181336 ( -0.027796 0.02793 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.9249e-07 ( -5.11331e-08 5.2431e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.244 sec. to 24.156 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.83664 ( -0.306072 0.740713 )
Epeak [keV] : 9999.35 ( -9999.35 -9999.36 )
Norm@50keV : 1.29426E-03 ( -0.000228141 0.00184823 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.38 using 59 PHA bins.
# Reduced chi-squared = 0.7925 for 56 degrees of freedom
# Null hypothesis probability = 8.687406e-01
Photon flux (15-150 keV) in 24.4 sec: 0.152258 ( -0.043999 0.041123 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.9555e-07 ( -6.39173e-08 5.82355e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.652 sec. to 1.652 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.02688 ( -0.311714 0.289388 )
Norm@50keV : 5.64993E-03 ( -0.00117672 0.00115127 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 65.75 using 59 PHA bins.
# Reduced chi-squared = 1.153 for 57 degrees of freedom
# Null hypothesis probability = 1.997191e-01
Photon flux (15-150 keV) in 1 sec: 0.858213 ( -0.14554 0.145737 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.21915e-08 ( -1.00345e-08 1.03358e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.652 sec. to 1.652 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.140907 ( -1.47534 2.23559 )
Epeak [keV] : 40.1650 ( -13.7404 14.4844 )
Norm@50keV : 6.99725E-02 ( -0.0701784 1.47088 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 60.47 using 59 PHA bins.
# Reduced chi-squared = 1.080 for 56 degrees of freedom
# Null hypothesis probability = 3.175968e-01
Photon flux (15-150 keV) in 1 sec: 0.804802 ( -0.14841 0.149938 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.51263e-08 ( -9.54515e-09 1.09656e-08 ) ergs/cm2
Time-resolved spectra