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 -1.208 sec. to 6.760 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.46189 ( -0.182666 0.182066 )
Norm@50keV : 1.08085E-02 ( -0.00114072 0.00113872 )
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#Fit statistic : Chi-Squared = 52.51 using 59 PHA bins.
# Reduced chi-squared = 0.9211 for 57 degrees of freedom
# Null hypothesis probability = 6.441854e-01
Photon flux (15-150 keV) in 7.968 sec: 1.33600 ( -0.14827 0.14882 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.22449e-07 ( -9.26902e-08 9.30742e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.208 sec. to 6.760 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.11156 ( -0.498816 0.822134 )
Epeak [keV] : 139.396 ( -67.9033 -139.393 )
Norm@50keV : 1.57605E-02 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 51.82 using 59 PHA bins.
# Reduced chi-squared = 0.9253 for 56 degrees of freedom
# Null hypothesis probability = 6.338429e-01
Photon flux (15-150 keV) in 7.968 sec: 1.31381 ( -0.15599 0.15546 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.10306e-07 ( -9.68789e-08 9.65315e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 1.948 sec. to 2.948 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.45868 ( -0.298903 0.298999 )
Norm@50keV : 1.82913E-02 ( -0.00321475 0.00321011 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.64 using 59 PHA bins.
# Reduced chi-squared = 0.9411 for 57 degrees of freedom
# Null hypothesis probability = 6.017522e-01
Photon flux (15-150 keV) in 1 sec: 2.25909 ( -0.41578 0.4179 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.74779e-07 ( -3.26901e-08 3.28892e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.948 sec. to 2.948 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.09954 ( -1.38869 1.41444 )
Epeak [keV] : 134.089 ( -134.089 -134.089 )
Norm@50keV : 2.72483E-02 ( -0.0119156 0.0954937 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.36 using 59 PHA bins.
# Reduced chi-squared = 0.9529 for 56 degrees of freedom
# Null hypothesis probability = 5.754241e-01
Photon flux (15-150 keV) in 1 sec: 2.22783 ( -0.42878 0.42891 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.71993e-07 ( -3.45065e-08 3.40747e-08 ) ergs/cm2
Time-resolved spectra