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 -20.444 sec. to 40.124 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.49638 ( -0.17681 0.175702 )
Norm@50keV : 1.89709E-03 ( -0.000190186 0.000189299 )
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#Fit statistic : Chi-Squared = 57.80 using 59 PHA bins.
# Reduced chi-squared = 1.014 for 57 degrees of freedom
# Null hypothesis probability = 4.454281e-01
Photon flux (15-150 keV) in 60.57 sec: 0.236607 ( -0.023919 0.02398 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.09085e-06 ( -1.19187e-07 1.201e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -20.444 sec. to 40.124 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.49374 ( -1.26079 0.616355 )
Epeak [keV] : 1.00000E+04 ( -10000 -10000 )
Norm@50keV : 1.90287E-03 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 57.80 using 59 PHA bins.
# Reduced chi-squared = 1.032 for 56 degrees of freedom
# Null hypothesis probability = 4.084649e-01
Photon flux (15-150 keV) in 60.57 sec: 0.236890 ( -0.024566 0.024007 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.09284e-06 ( -1.30236e-07 1.01416e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 17.388 sec. to 18.388 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.00149 ( -0.635481 0.537988 )
Norm@50keV : 3.67768E-03 ( -0.00153992 0.00147723 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 68.02 using 59 PHA bins.
# Reduced chi-squared = 1.193 for 57 degrees of freedom
# Null hypothesis probability = 1.506281e-01
Photon flux (15-150 keV) in 1 sec: 0.552066 ( -0.180732 0.180763 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.39297e-08 ( -1.284e-08 1.3652e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 17.388 sec. to 18.388 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.333077 ( -1.82698 0.300948 )
Epeak [keV] : 37.9970 ( )
Norm@50keV : 3.85922E-02 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 66.86 using 59 PHA bins.
# Reduced chi-squared = 1.194 for 56 degrees of freedom
# Null hypothesis probability = 1.518330e-01
Photon flux (15-150 keV) in 1 sec: 0.531740 ( -0.204529 0.183731 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.89514e-08 ( -1.37515e-08 1.56995e-08 ) ergs/cm2
Time-resolved spectra