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 318.376 sec. to 627.744 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.81356 ( -0.137419 0.1341 )
Norm@50keV : 7.66940E-04 ( -5.98188e-05 5.87748e-05 )
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#Fit statistic : Chi-Squared = 60.81 using 59 PHA bins.
# Reduced chi-squared = 1.067 for 57 degrees of freedom
# Null hypothesis probability = 3.404404e-01
Photon flux (15-150 keV) in 309.4 sec: 0.106249 ( -0.0071166 0.00713 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.18389e-06 ( -1.72108e-07 1.74582e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 318.376 sec. to 627.744 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.30284 ( -0.139141 0.54945 )
Epeak [keV] : 112.858 ( )
Norm@50keV : 4.45188E-04 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.61 using 59 PHA bins.
# Reduced chi-squared = 1.047 for 56 degrees of freedom
# Null hypothesis probability = 3.800376e-01
Photon flux (15-150 keV) in 309.4 sec: 8.99767E-02 ( -0.0147384 0.0122453 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.90823e-06 ( -2.30852e-07 1.97733e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 409.700 sec. to 410.700 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.98042 ( -0.809983 0.722189 )
Norm@50keV : 1.97128E-03 ( -0.00102612 0.000995049 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 72.69 using 59 PHA bins.
# Reduced chi-squared = 1.275 for 57 degrees of freedom
# Null hypothesis probability = 7.863088e-02
Photon flux (15-150 keV) in 1 sec: 0.293082 ( -0.110281 0.110406 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.81648e-08 ( -8.37779e-09 9.56649e-09 ) ergs/cm2
Cutoff power-law model
Time interval is from 409.700 sec. to 410.700 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 10 ( -4.83481 -10 )
Epeak [keV] : 25.8499 ( -2.9396 3.31049 )
Norm@50keV : 1.87277E+06 ( -1.87174e+06 5.70589e+06 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 63.81 using 59 PHA bins.
# Reduced chi-squared = 1.140 for 56 degrees of freedom
# Null hypothesis probability = 2.209794e-01
Photon flux (15-150 keV) in 1 sec: 0.292941 ( -0.178655 0.111112 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.89671e-08 ( -1.551e-08 6.79374e-09 ) ergs/cm2
Time-resolved spectra
