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 -20.496 sec. to 106.492 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.27 ( -0.0647763 0.0650173 )
Norm@50keV : 3.66994E-03 ( -0.000115863 0.000115819 )
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#Fit statistic : Chi-Squared = 61.17 using 59 PHA bins.
# Reduced chi-squared = 1.073 for 57 degrees of freedom
# Null hypothesis probability = 3.286188e-01
Photon flux (15-150 keV) in 127 sec: 0.435510 ( -0.014836 0.014921 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.64091e-06 ( -1.60439e-07 1.60997e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -20.496 sec. to 106.492 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.26481 ( -0.0663852 0.0642971 )
Epeak [keV] : 9999.35 ( -9999.36 -9999.36 )
Norm@50keV : 3.68524E-03 ( -0.000115857 0.000433316 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 61.38 using 59 PHA bins.
# Reduced chi-squared = 1.096 for 56 degrees of freedom
# Null hypothesis probability = 2.892792e-01
Photon flux (15-150 keV) in 127 sec: 0.435387 ( -0.01486 0.014899 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.67933e-06 ( -2.00919e-07 1.20589e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 24.680 sec. to 25.680 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.23648 ( -0.169763 0.170409 )
Norm@50keV : 1.67943E-02 ( -0.00151453 0.00151155 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 60.02 using 59 PHA bins.
# Reduced chi-squared = 1.053 for 57 degrees of freedom
# Null hypothesis probability = 3.669285e-01
Photon flux (15-150 keV) in 1 sec: 1.98204 ( -0.17926 0.17952 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.68702e-07 ( -1.77566e-08 1.79875e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 24.680 sec. to 25.680 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.10816 ( -0.173403 0.271026 )
Epeak [keV] : 39.6177 ( -9999.36 -9999.36 )
Norm@50keV : 5.23895E-03 ( -0.00184635 0.00158911 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.97 using 59 PHA bins.
# Reduced chi-squared = 1.053 for 56 degrees of freedom
# Null hypothesis probability = 3.676036e-01
Photon flux (15-150 keV) in 1 sec: 1.98162 ( -0.17932 0.17944 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.08177e-08 ( -1.8745e-08 1.68249e-08 ) ergs/cm2
Time-resolved spectra
