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 -1.220 sec. to 65.576 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.55949 ( -0.0638422 0.06365 )
Norm@50keV : 4.93882E-03 ( -0.000173547 0.000173378 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 52.01 using 59 PHA bins.
# Reduced chi-squared = 0.9124 for 57 degrees of freedom
# Null hypothesis probability = 6.623564e-01
Photon flux (15-150 keV) in 66.8 sec: 0.626973 ( -0.023062 0.023115 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.10211e-06 ( -1.16609e-07 1.1701e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.220 sec. to 65.576 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.02753 ( -0.263606 0.280397 )
Epeak [keV] : 94.0828 ( -16.3554 41.5679 )
Norm@50keV : 8.95200E-03 ( -0.00223442 0.00320631 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 39.41 using 59 PHA bins.
# Reduced chi-squared = 0.7037 for 56 degrees of freedom
# Null hypothesis probability = 9.546882e-01
Photon flux (15-150 keV) in 66.8 sec: 0.605805 ( -0.025053 0.02511 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.97589e-06 ( -1.32104e-07 1.32081e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 46.604 sec. to 47.604 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.20494 ( -0.0631408 0.0631831 )
Norm@50keV : 5.32490E-02 ( -0.00199675 0.00199675 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 69.58 using 59 PHA bins.
# Reduced chi-squared = 1.221 for 57 degrees of freedom
# Null hypothesis probability = 1.224860e-01
Photon flux (15-150 keV) in 1 sec: 6.25476 ( -0.24155 0.24174 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.39548e-07 ( -2.22748e-08 2.23274e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 46.604 sec. to 47.604 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.482849 ( -0.272645 0.28975 )
Epeak [keV] : 117.254 ( -18.776 37.2298 )
Norm@50keV : 0.114099 ( -0.0278407 0.0393437 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 47.16 using 59 PHA bins.
# Reduced chi-squared = 0.8421 for 56 degrees of freedom
# Null hypothesis probability = 7.939335e-01
Photon flux (15-150 keV) in 1 sec: 6.07691 ( -0.2494 0.24962 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.22264e-07 ( -2.3747e-08 2.36824e-08 ) ergs/cm2
Time-resolved spectra
