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 -8.116 sec. to 4.984 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.23705 ( -0.268361 0.245086 )
Norm@50keV : 3.57836E-03 ( -0.000662073 0.00064465 )
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#Fit statistic : Chi-Squared = 47.73 using 59 PHA bins.
# Reduced chi-squared = 0.8373 for 57 degrees of freedom
# Null hypothesis probability = 8.042988e-01
Photon flux (15-150 keV) in 13.1 sec: 0.604257 ( -0.082611 0.082659 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.43263e-07 ( -6.95305e-08 7.10186e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -8.116 sec. to 4.984 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.442977 ( -1.41153 1.7848 )
Epeak [keV] : 34.0964 ( -20.9797 8.05439 )
Norm@50keV : 4.18419E-02 ( -0.0418439 0.440686 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 42.80 using 59 PHA bins.
# Reduced chi-squared = 0.7644 for 56 degrees of freedom
# Null hypothesis probability = 9.026213e-01
Photon flux (15-150 keV) in 13.1 sec: 0.574450 ( -0.08503 0.08549 ) ph/cm2/s
Energy fluence (15-150 keV) : 0 ( 0 0 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 3.420 sec. to 4.420 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.52175 ( -0.38541 0.385637 )
Norm@50keV : 9.64937E-03 ( -0.0022558 0.00225046 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 71.25 using 59 PHA bins.
# Reduced chi-squared = 1.250 for 57 degrees of freedom
# Null hypothesis probability = 9.709881e-02
Photon flux (15-150 keV) in 1 sec: 1.21182 ( -0.296484 0.29878 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.12347e-08 ( -2.23377e-08 2.24809e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 3.420 sec. to 4.420 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.669032 ( -1.18362 2.84982 )
Epeak [keV] : 77.8568 ( -30.5829 -77.824 )
Norm@50keV : 2.62778E-02 ( -0.026306 4.18445 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 70.58 using 59 PHA bins.
# Reduced chi-squared = 1.260 for 56 degrees of freedom
# Null hypothesis probability = 9.093618e-02
Photon flux (15-150 keV) in 1 sec: 1.18110 ( -0.307515 0.30579 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.69601e-08 ( -2.7446e-08 2.44668e-08 ) ergs/cm2
Time-resolved spectra