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 -81.072 sec. to 16.784 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.91784 ( -0.239715 0.225357 )
Norm@50keV : 1.39331E-03 ( -0.000223385 0.000217549 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 46.52 using 59 bins.
Reduced chi-squared = 0.81614
# Null hypothesis probability of 8.38e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 97.86 sec: 0.201498 ( -0.024838 0.024838 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.25405e-06 ( -1.9224e-07 1.97983e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -81.072 sec. to 16.784 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.33441 ( -0.778934 1.071 )
Epeak [keV] : 47.2292 ( -45.8543 -47.2292 )
Norm@50keV : 3.04777E-03 ( -0.0030478 0.00968434 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 45.26 using 59 bins.
Reduced chi-squared = 0.808214
# Null hypothesis probability of 8.47e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 97.86 sec: 0.197352 ( -0.025479 0.025551 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.17656e-06 ( -2.08026e-07 2.2698e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from -0.132 sec. to 0.868 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.91109 ( -0.389502 0.353413 )
Norm@50keV : 8.51229E-03 ( -0.00232082 0.0022499 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 63.14 using 59 bins.
Reduced chi-squared = 1.10772
# Null hypothesis probability of 2.68e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.22747 ( -0.264896 0.26491 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.82871e-08 ( -2.02641e-08 2.11595e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.132 sec. to 0.868 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.550152 ( -1.5399 2.90733 )
Epeak [keV] : 41.9529 ( -41.9417 78.488 )
Norm@50keV : 5.64273E-02 ( -0.0565738 4.20011 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 60.95 using 59 bins.
Reduced chi-squared = 1.08839
# Null hypothesis probability of 3.02e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.19643 ( -0.264396 0.26582 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.90542e-08 ( -1.99193e-08 2.32093e-08 ) ergs/cm2
Time-resolved spectra
