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 -6.368 sec. to 46.300 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.07199 ( -0.203974 0.19118 )
Norm@50keV : 2.29059E-03 ( -0.000297467 0.000289584 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 63.84 using 59 bins.
Reduced chi-squared = 1.12
# Null hypothesis probability of 2.49e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 52.67 sec: 0.355495 ( -0.036831 0.036872 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.11829e-06 ( -1.31775e-07 1.33592e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -6.368 sec. to 46.300 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.5803 ( -0.504552 0.896187 )
Epeak [keV] : 38.5577 ( -20.1288 -38.5571 )
Norm@50keV : 4.25578E-03 ( -0.00227765 0.00869283 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 62.65 using 59 bins.
Reduced chi-squared = 1.11875
# Null hypothesis probability of 2.52e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 52.67 sec: 0.348216 ( -0.038673 0.038554 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.08077e-06 ( -1.40804e-07 1.44925e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.184 sec. to 1.184 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.84743 ( -0.525137 0.462978 )
Norm@50keV : 7.10883E-03 ( -0.00217072 0.00200764 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 37.41 using 59 bins.
Reduced chi-squared = 0.656316
# Null hypothesis probability of 9.79e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.998237 ( -0.259189 0.259333 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.53762e-08 ( -1.90091e-08 1.91906e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.184 sec. to 1.184 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.75864 ( -0.257004 1.85107 )
Epeak [keV] : 247.690 ( )
Norm@50keV : 2.56696E-03 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared 36.84 using 59 bins.
Reduced chi-squared = 0.657857
# Null hypothesis probability of 9.78e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.840004 ( -0.419309 0.407806 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.68683e-08 ( -2.8179e-08 2.10662e-08 ) ergs/cm2
Time-resolved spectra
