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 18.448 sec. to 65.980 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.47473 ( -0.340055 0.298945 )
Norm@50keV : 1.71061E-03 ( -0.00041329 0.000407989 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 42.81 using 59 bins.
Reduced chi-squared = 0.751053
# Null hypothesis probability of 9.19e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 47.53 sec: 0.330961 ( -0.047237 0.047228 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.07806e-07 ( -1.4324e-07 1.49913e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 18.448 sec. to 65.980 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.25114 ( -0.745727 2.25513 )
Epeak [keV] : 21.5296 ( -18.9323 11.3201 )
Norm@50keV : 1.02970E-02 ( -0.0103021 0.315025 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 40.95 using 59 bins.
Reduced chi-squared = 0.73125
# Null hypothesis probability of 9.34e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 47.53 sec: 0.319775 ( -0.048422 0.048897 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.24647e-07 ( -1.41635e-07 1.74453e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 49.936 sec. to 50.936 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.62775 ( -0.938474 0.813346 )
Norm@50keV : 5.97708E-03 ( -0.00276015 0.00244191 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 44.71 using 59 bins.
Reduced chi-squared = 0.784386
# Null hypothesis probability of 8.81e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.774879 ( -0.311265 0.312291 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.57237e-08 ( -2.48989e-08 2.5492e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 49.936 sec. to 50.936 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -4.1801 ( -0.610028 4.29731 )
Epeak [keV] : 498.736 ( )
Norm@50keV : 3.97153E-04 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared 44.14 using 59 bins.
Reduced chi-squared = 0.788214
# Null hypothesis probability of 8.74e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.582443 ( -0.582443 0.482077 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.30491e-08 ( -3.25261e-08 2.18637e-07 ) ergs/cm2
Time-resolved spectra
