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 -12.980 sec. to 15.512 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.32426 ( -0.0593623 0.0594856 )
Norm@50keV : 1.02825E-02 ( -0.000338894 0.000338894 )
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#Fit statistic : Chi-Squared = 54.35 using 59 PHA bins.
# Reduced chi-squared = 0.9534 for 57 degrees of freedom
# Null hypothesis probability = 5.752514e-01
Photon flux (15-150 keV) in 28.49 sec: 1.23240 ( -0.04304 0.04311 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.87849e-06 ( -1.02788e-07 1.02996e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -12.980 sec. to 15.512 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.927525 ( -0.243389 0.257859 )
Epeak [keV] : 147.687 ( -37.4967 138.491 )
Norm@50keV : 1.57030E-02 ( -0.00350909 0.00482301 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 46.35 using 59 PHA bins.
# Reduced chi-squared = 0.8278 for 56 degrees of freedom
# Null hypothesis probability = 8.174606e-01
Photon flux (15-150 keV) in 28.49 sec: 1.20472 ( -0.04599 0.04605 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.80661e-06 ( -1.12831e-07 1.12443e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.540 sec. to 1.540 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.06905 ( -0.124686 0.12622 )
Norm@50keV : 2.64976E-02 ( -0.00200854 0.00200716 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 59.87 using 59 PHA bins.
# Reduced chi-squared = 1.050 for 57 degrees of freedom
# Null hypothesis probability = 3.718275e-01
Photon flux (15-150 keV) in 1 sec: 3.06499 ( -0.23734 0.23762 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.79866e-07 ( -2.30571e-08 2.3174e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.540 sec. to 1.540 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.274293 ( -0.555017 0.637936 )
Epeak [keV] : 123.016 ( -31.616 144.627 )
Norm@50keV : 6.06299E-02 ( -0.0261365 0.0540655 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.62 using 59 PHA bins.
# Reduced chi-squared = 0.9575 for 56 degrees of freedom
# Null hypothesis probability = 5.653944e-01
Photon flux (15-150 keV) in 1 sec: 2.98284 ( -0.24546 0.24483 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.70608e-07 ( -2.46789e-08 2.45537e-08 ) ergs/cm2
Time-resolved spectra
