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 -159.376 sec. to 162.428 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.58023 ( -0.0476839 0.0476638 )
Norm@50keV : 3.37104E-03 ( -8.35712e-05 8.35664e-05 )
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#Fit statistic : Chi-Squared = 65.94 using 59 PHA bins.
# Reduced chi-squared = 1.157 for 57 degrees of freedom
# Null hypothesis probability = 1.950995e-01
Photon flux (15-150 keV) in 321.8 sec: 0.430598 ( -0.012073 0.012118 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.01717e-05 ( -2.62374e-07 2.62862e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -159.376 sec. to 162.428 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.30546 ( -0.188844 0.197141 )
Epeak [keV] : 137.135 ( -35.5131 166.33 )
Norm@50keV : 4.51152E-03 ( -0.000799035 0.00101921 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 59.67 using 59 PHA bins.
# Reduced chi-squared = 1.066 for 56 degrees of freedom
# Null hypothesis probability = 3.438031e-01
Photon flux (15-150 keV) in 321.8 sec: 0.421092 ( -0.01353 0.013599 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.96911e-06 ( -2.97112e-07 2.96297e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from -0.332 sec. to 0.668 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.09862 ( -0.103499 0.104505 )
Norm@50keV : 3.14154E-02 ( -0.00190835 0.0019053 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.15 using 59 PHA bins.
# Reduced chi-squared = 0.9324 for 57 degrees of freedom
# Null hypothesis probability = 6.203525e-01
Photon flux (15-150 keV) in 1 sec: 3.64350 ( -0.22821 0.22853 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.28632e-07 ( -2.14753e-08 2.1555e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.332 sec. to 0.668 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.799176 ( -0.341989 0.428472 )
Epeak [keV] : 231.874 ( )
Norm@50keV : 4.27352E-02 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 51.47 using 59 PHA bins.
# Reduced chi-squared = 0.9190 for 56 degrees of freedom
# Null hypothesis probability = 6.469605e-01
Photon flux (15-150 keV) in 1 sec: 3.60317 ( -0.23406 0.23429 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.25095e-07 ( -2.22782e-08 2.22012e-08 ) ergs/cm2
Time-resolved spectra
