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 -0.144 sec. to 2.984 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.58412 ( -0.228665 0.221664 )
Norm@50keV : 5.68834E-03 ( -0.000834614 0.00082301 )
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#Fit statistic : Chi-Squared = 48.44 using 59 PHA bins.
# Reduced chi-squared = 0.8498 for 57 degrees of freedom
# Null hypothesis probability = 7.830204e-01
Photon flux (15-150 keV) in 3.128 sec: 0.727454 ( -0.098314 0.098348 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.66754e-07 ( -2.6183e-08 2.66636e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.144 sec. to 2.984 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.553655 ( -1.02092 1.25179 )
Epeak [keV] : 64.3323 ( -15.7167 171.089 )
Norm@50keV : 2.05906E-02 ( -0.0205906 0.0768661 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.98 using 59 PHA bins.
# Reduced chi-squared = 0.8032 for 56 degrees of freedom
# Null hypothesis probability = 8.542628e-01
Photon flux (15-150 keV) in 3.128 sec: 0.703530 ( -0.101051 0.100964 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.5284e-07 ( -2.80279e-08 2.94768e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from -0.144 sec. to 0.856 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.32702 ( -0.250907 0.248783 )
Norm@50keV : 9.87735E-03 ( -0.00151206 0.00150582 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 49.25 using 59 PHA bins.
# Reduced chi-squared = 0.8640 for 57 degrees of freedom
# Null hypothesis probability = 7.576875e-01
Photon flux (15-150 keV) in 1 sec: 1.18448 ( -0.17993 0.18009 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.69907e-08 ( -1.6577e-08 1.68035e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.144 sec. to 0.856 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.535738 ( -0.894744 1.24068 )
Epeak [keV] : 95.8438 ( -32.6196 -95.8433 )
Norm@50keV : 2.42451E-02 ( -0.0151384 0.0689704 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 47.30 using 59 PHA bins.
# Reduced chi-squared = 0.8447 for 56 degrees of freedom
# Null hypothesis probability = 7.894786e-01
Photon flux (15-150 keV) in 1 sec: 1.15331 ( -0.18494 0.18449 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.9819e-08 ( -1.84379e-08 1.47819e-08 ) ergs/cm2
Time-resolved spectra