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 16.400 sec. to 22.400 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.25501 ( -0.248181 0.254717 )
Norm@50keV : 1.27328E-02 ( -0.00184148 0.00183894 )
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#Fit statistic : Chi-Squared = 39.86 using 59 PHA bins.
# Reduced chi-squared = 0.6993 for 57 degrees of freedom
# Null hypothesis probability = 9.588832e-01
Photon flux (15-150 keV) in 6 sec: 1.50719 ( -0.23103 0.23231 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.63662e-07 ( -1.16488e-07 1.16963e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 16.400 sec. to 22.400 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.987738 ( -0.499084 1.12387 )
Epeak [keV] : 214.376 ( -214.376 -214.376 )
Norm@50keV : 1.68520E-02 ( -0.00577905 0.0348781 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 39.63 using 59 PHA bins.
# Reduced chi-squared = 0.7077 for 56 degrees of freedom
# Null hypothesis probability = 9.520375e-01
Photon flux (15-150 keV) in 6 sec: 1.49008 ( -0.23934 0.23974 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.5558e-07 ( -1.21796e-07 1.20374e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 19.500 sec. to 20.500 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.59719 ( -0.614612 0.560072 )
Norm@50keV : 1.52165E-02 ( -0.00527257 0.00502962 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 75.86 using 59 PHA bins.
# Reduced chi-squared = 1.331 for 57 degrees of freedom
# Null hypothesis probability = 4.816096e-02
Photon flux (15-150 keV) in 1 sec: 1.95375 ( -0.63296 0.63438 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.42374e-07 ( -5.08321e-08 5.16431e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 19.500 sec. to 20.500 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.59424 ( -0.676694 1.36853 )
Epeak [keV] : 9998.91 ( -9999.35 -9999.35 )
Norm@50keV : 1.52625E-02 ( -0.0152556 0.132141 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 75.86 using 59 PHA bins.
# Reduced chi-squared = 1.355 for 56 degrees of freedom
# Null hypothesis probability = 3.980827e-02
Photon flux (15-150 keV) in 1 sec: 1.96384 ( -0.71064 0.69182 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.43433e-07 ( -6.00438e-08 5.11747e-08 ) ergs/cm2
Time-resolved spectra
