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 -40.076 sec. to 108.740 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.82825 ( -0.103493 0.101906 )
Norm@50keV : 2.20505E-03 ( -0.000138944 0.000137814 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 63.44 using 59 bins.
Reduced chi-squared = 1.11298
# Null hypothesis probability of 2.60e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 148.8 sec: 0.307260 ( -0.017606 0.017627 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.01859e-06 ( -1.91735e-07 1.93468e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -40.076 sec. to 108.740 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.09888 ( -0.453431 0.513994 )
Epeak [keV] : 54.6026 ( -8.30257 20.782 )
Norm@50keV : 5.55578E-03 ( -0.00239209 0.00506099 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 55.38 using 59 bins.
Reduced chi-squared = 0.988929
# Null hypothesis probability of 4.98e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 148.8 sec: 0.296274 ( -0.018802 0.018802 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.80281e-06 ( -2.24871e-07 2.29912e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.088 sec. to 1.088 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.2913 ( -0.18543 0.187622 )
Norm@50keV : 1.89953E-02 ( -0.00215414 0.00215205 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 63.06 using 59 bins.
Reduced chi-squared = 1.10632
# Null hypothesis probability of 2.71e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 2.26262 ( -0.26213 0.26256 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.88131e-07 ( -2.34286e-08 2.36076e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.088 sec. to 1.088 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.673076 ( -0.687572 0.866308 )
Epeak [keV] : 109.557 ( -37.8387 -109.558 )
Norm@50keV : 3.87457E-02 ( -0.0206344 0.064246 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 60.90 using 59 bins.
Reduced chi-squared = 1.0875
# Null hypothesis probability of 3.04e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 2.21741 ( -0.26835 0.26819 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.80393e-07 ( -2.58355e-08 2.55561e-08 ) ergs/cm2
Time-resolved spectra
