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 -0.148 sec. to 22.764 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.83384 ( -0.141038 0.13723 )
Norm@50keV : 5.59898E-03 ( -0.00046601 0.00045856 )
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#Fit statistic : Chi-Squared 55.12 using 59 bins.
Reduced chi-squared = 0.967018
# Null hypothesis probability of 5.46e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 22.91 sec: 0.781925 ( -0.055599 0.055668 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.17995e-06 ( -9.83584e-08 9.98251e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.148 sec. to 22.764 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.77767 ( -0.497468 0.53141 )
Epeak [keV] : 179.309 ( -129.808 -179.337 )
Norm@50keV : 6.00710E-03 ( -0.0022793 0.00551084 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 55.08 using 59 bins.
Reduced chi-squared = 0.983571
# Null hypothesis probability of 5.10e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 22.91 sec: 0.779489 ( -0.059374 0.057605 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.17275e-06 ( -1.15798e-07 1.0544e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 10.832 sec. to 11.832 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.73958 ( -0.255462 0.243651 )
Norm@50keV : 1.39035E-02 ( -0.00229202 0.0022371 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 34.77 using 59 bins.
Reduced chi-squared = 0.61
# Null hypothesis probability of 9.91e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.87290 ( -0.26689 0.26695 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.28396e-07 ( -2.1643e-08 2.20844e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 10.832 sec. to 11.832 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.23818 ( -0.882495 1.13246 )
Epeak [keV] : 67.2517 ( -54.733 -67.2526 )
Norm@50keV : 2.65635E-02 ( -0.026563 0.0872649 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 33.95 using 59 bins.
Reduced chi-squared = 0.60625
# Null hypothesis probability of 9.91e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.84501 ( -0.27192 0.27193 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.22535e-07 ( -2.36e-08 2.45235e-08 ) ergs/cm2
Time-resolved spectra
