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 0.016 sec. to 30.816 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.70705 ( -0.193742 0.187894 )
Norm@50keV : 1.65536E-03 ( -0.000202466 0.000198958 )
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#Fit statistic : Chi-Squared = 49.68 using 59 PHA bins.
# Reduced chi-squared = 0.8715 for 57 degrees of freedom
# Null hypothesis probability = 7.435738e-01
Photon flux (15-150 keV) in 30.8 sec: 0.220404 ( -0.023554 0.023559 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.71868e-07 ( -6.00736e-08 6.12098e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.016 sec. to 30.816 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.27968 ( -0.391721 0.886019 )
Epeak [keV] : 73.3883 ( -20.2481 -73.3895 )
Norm@50keV : 2.88540E-03 ( -0.00155845 0.00628865 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.71 using 59 PHA bins.
# Reduced chi-squared = 0.8698 for 56 degrees of freedom
# Null hypothesis probability = 7.445537e-01
Photon flux (15-150 keV) in 30.8 sec: 0.216772 ( -0.024402 0.024363 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.49458e-07 ( -7.05967e-08 7.17973e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 6.692 sec. to 7.692 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.67134 ( -0.200448 0.193129 )
Norm@50keV : 9.68792E-03 ( -0.00126216 0.00124193 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 65.03 using 59 PHA bins.
# Reduced chi-squared = 1.141 for 57 degrees of freedom
# Null hypothesis probability = 2.172657e-01
Photon flux (15-150 keV) in 1 sec: 1.27410 ( -0.14721 0.14724 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.99311e-08 ( -1.22939e-08 1.25114e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 6.692 sec. to 7.692 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.756216 ( -0.84582 1.09916 )
Epeak [keV] : 59.5961 ( -14.5435 149.581 )
Norm@50keV : 3.15849E-02 ( -0.0315854 0.102726 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 61.59 using 59 PHA bins.
# Reduced chi-squared = 1.100 for 56 degrees of freedom
# Null hypothesis probability = 2.830847e-01
Photon flux (15-150 keV) in 1 sec: 1.23740 ( -0.15096 0.15109 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.23323e-08 ( -1.37945e-08 1.43062e-08 ) ergs/cm2
Time-resolved spectra
