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 -179.000 sec. to 963.064 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.83102 ( -0.318958 0.298458 )
Norm@50keV : 1.99768E-04 ( -4.27465e-05 4.14519e-05 )
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#Fit statistic : Chi-Squared = 63.18 using 59 PHA bins.
# Reduced chi-squared = 1.108 for 57 degrees of freedom
# Null hypothesis probability = 2.672909e-01
Photon flux (15-150 keV) in 1142 sec: 2.78672E-02 ( -0.0046232 0.0046239 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.09868e-06 ( -4.39219e-07 4.60122e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -179.000 sec. to 963.064 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.44935 ( -0.755796 1.35019 )
Epeak [keV] : 57.0008 ( -49.8236 -57.0052 )
Norm@50keV : 3.39882E-04 ( -0.000339803 0.00212706 )
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#Fit statistic : Chi-Squared = 62.76 using 59 PHA bins.
# Reduced chi-squared = 1.121 for 56 degrees of freedom
# Null hypothesis probability = 2.492574e-01
Photon flux (15-150 keV) in 1142 sec: 2.74676E-02 ( -0.0047115 0.004729 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.98393e-06 ( -5.14711e-07 4.98782e-07 ) ergs/cm2
1-s peak spectrum fit
1-s peak spectrum unavailable, likely because there are no event data in the 1-s peak range.
Time-resolved spectra