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 -36.304 sec. to 185.844 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.52129 ( -0.235684 0.231294 )
Norm@50keV : 7.13491E-04 ( -8.5991e-05 8.44357e-05 )
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#Fit statistic : Chi-Squared = 70.74 using 59 PHA bins.
# Reduced chi-squared = 1.241 for 57 degrees of freedom
# Null hypothesis probability = 1.042585e-01
Photon flux (15-150 keV) in 222.1 sec: 8.95939E-02 ( -0.0103383 0.0103625 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.49837e-06 ( -2.01044e-07 2.03784e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -36.304 sec. to 185.844 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -3.48933 ( -0.484835 1.27833 )
Epeak [keV] : 386.211 ( -68.1138 109.165 )
Norm@50keV : 8.84591E-05 ( -9.00594e-05 0.000214362 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 63.38 using 59 PHA bins.
# Reduced chi-squared = 1.132 for 56 degrees of freedom
# Null hypothesis probability = 2.322711e-01
Photon flux (15-150 keV) in 222.1 sec: 8.96023E-02 ( -0.0103648 0.0103408 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.49744e-06 ( -2.1168e-07 2.15608e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 8.760 sec. to 9.760 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.60372 ( -3.19809 1.13258 )
Norm@50keV : 3.65410E-03 ( -0.00364167 0.00145217 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 72.02 using 59 PHA bins.
# Reduced chi-squared = 1.264 for 57 degrees of freedom
# Null hypothesis probability = 8.682196e-02
Photon flux (15-150 keV) in 1 sec: 0.470899 ( -0.174826 0.171228 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.37746e-08 ( -2.30453e-08 1.77791e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 8.760 sec. to 9.760 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -7.954 ( )
Epeak [keV] : 776.480 ( )
Norm@50keV : 5.03134E-06 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 62.03 using 59 PHA bins.
# Reduced chi-squared = 1.108 for 56 degrees of freedom
# Null hypothesis probability = 2.699655e-01
Photon flux (15-150 keV) in 1 sec: 0.308493 ( -0.229983 0.030675 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.81589e-08 ( -1.52729e-08 1.68227e-08 ) ergs/cm2
Time-resolved spectra