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 -24.620 sec. to 161.080 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.79909 ( -0.0867423 0.0857981 )
Norm@50keV : 2.57317E-03 ( -0.000126587 0.00012584 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 44.27 using 59 bins.
Reduced chi-squared = 0.776667
# Null hypothesis probability of 8.91e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 185.7 sec: 0.354469 ( -0.01688 0.016915 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.39979e-06 ( -2.20602e-07 2.21806e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -24.620 sec. to 161.080 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.63334 ( -0.235639 0.343946 )
Epeak [keV] : 104.956 ( -42.6992 -104.957 )
Norm@50keV : 3.14206E-03 ( -0.000673442 0.00157133 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 43.50 using 59 bins.
Reduced chi-squared = 0.776786
# Null hypothesis probability of 8.89e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 185.7 sec: 0.351013 ( -0.018115 0.01812 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.33283e-06 ( -2.55909e-07 2.49772e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 116.284 sec. to 117.284 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.58624 ( -0.14122 0.138439 )
Norm@50keV : 1.62217E-02 ( -0.00139728 0.00138554 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 56.03 using 59 bins.
Reduced chi-squared = 0.982982
# Null hypothesis probability of 5.11e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 2.07584 ( -0.16821 0.16832 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.51988e-07 ( -1.41148e-08 1.42805e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 116.284 sec. to 117.284 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.825574 ( -0.617601 0.727336 )
Epeak [keV] : 73.5289 ( -16.4939 103.308 )
Norm@50keV : 4.06429E-02 ( -0.0210435 0.0559821 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 51.50 using 59 bins.
Reduced chi-squared = 0.919643
# Null hypothesis probability of 6.46e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 2.01023 ( -0.17756 0.17654 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.42702e-07 ( -1.58784e-08 1.61234e-08 ) ergs/cm2
Time-resolved spectra
