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 0.024 sec. to 76.296 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.41004 ( -0.11228 0.112865 )
Norm@50keV : 3.95849E-03 ( -0.000236793 0.000236557 )
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#Fit statistic : Chi-Squared 39.43 using 59 bins.
Reduced chi-squared = 0.691754
# Null hypothesis probability of 9.63e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 76.27 sec: 0.483189 ( -0.030355 0.030507 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.91174e-06 ( -1.90775e-07 1.91841e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.024 sec. to 76.296 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.4105 ( -0.109761 0.200775 )
Epeak [keV] : 9999.36 ( -9999.36 -9999.36 )
Norm@50keV : 3.96641E-03 ( -0.000236863 0.00127824 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 39.46 using 59 bins.
Reduced chi-squared = 0.704643
# Null hypothesis probability of 9.54e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 76.27 sec: 0.485381 ( -0.032675 0.028199 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.92465e-06 ( -2.50943e-07 2.25156e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 10.604 sec. to 11.604 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.27607 ( -0.139969 0.139841 )
Norm@50keV : 3.89356E-02 ( -0.00322736 0.00321635 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 47.76 using 59 bins.
Reduced chi-squared = 0.837895
# Null hypothesis probability of 8.03e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 4.62530 ( -0.38142 0.38161 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.87097e-07 ( -3.64582e-08 3.68289e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 10.604 sec. to 11.604 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.789672 ( -0.537227 0.647067 )
Epeak [keV] : 126.449 ( -46.2396 -126.447 )
Norm@50keV : 6.82252E-02 ( -0.0306082 0.0729005 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 45.61 using 59 bins.
Reduced chi-squared = 0.814464
# Null hypothesis probability of 8.38e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 4.53750 ( -0.39706 0.39498 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.72538e-07 ( -4.09109e-08 4.07093e-08 ) ergs/cm2
Time-resolved spectra
