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 -0.972 sec. to 3.016 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.05882 ( -0.175524 0.167354 )
Norm@50keV : 8.85397E-03 ( -0.00103028 0.00101239 )
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#Fit statistic : Chi-Squared 69.74 using 59 bins.
Reduced chi-squared = 1.22351
# Null hypothesis probability of 1.20e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 3.988 sec: 1.36543 ( -0.13143 0.13155 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.26945e-07 ( -3.51522e-08 3.55772e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.972 sec. to 3.016 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.700801 ( -0.951991 1.2825 )
Epeak [keV] : 39.2903 ( -9.31124 8.67474 )
Norm@50keV : 5.41372E-02 ( -0.0542169 0.254605 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 63.17 using 59 bins.
Reduced chi-squared = 1.12804
# Null hypothesis probability of 2.38e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 3.988 sec: 1.30149 ( -0.13976 0.13917 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.92284e-07 ( -3.86982e-08 4.16535e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.532 sec. to 1.532 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.84901 ( -0.232339 0.221014 )
Norm@50keV : 1.41730E-02 ( -0.00215606 0.00211571 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 78.74 using 59 bins.
Reduced chi-squared = 1.3814
# Null hypothesis probability of 2.98e-02 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.99147 ( -0.26961 0.26991 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.30341e-07 ( -1.96531e-08 1.99213e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.532 sec. to 1.532 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.477153 ( -1.88774 3.41005 )
Epeak [keV] : 43.5052 ( -6.34818 19.8681 )
Norm@50keV : 0.312166 ( -0.33181 32.0057 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 73.58 using 59 bins.
Reduced chi-squared = 1.31393
# Null hypothesis probability of 5.76e-02 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.84143 ( -0.31086 0.30455 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.07406e-07 ( -2.156e-08 2.69014e-08 ) ergs/cm2
Time-resolved spectra
