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 -1.968 sec. to 126.768 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.88922 ( -0.242888 0.228046 )
Norm@50keV : 5.57795E-04 ( -8.94779e-05 8.70886e-05 )
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#Fit statistic : Chi-Squared = 41.77 using 59 PHA bins.
# Reduced chi-squared = 0.7329 for 57 degrees of freedom
# Null hypothesis probability = 9.349251e-01
Photon flux (15-150 keV) in 128.7 sec: 7.96904E-02 ( -0.0101109 0.0101113 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.60068e-07 ( -1.02499e-07 1.05262e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.968 sec. to 126.768 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.30705 ( -0.863022 1.10097 )
Epeak [keV] : 50.2172 ( -40.4617 -50.2172 )
Norm@50keV : 1.20671E-03 ( -0.00120671 0.00409062 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 40.50 using 59 PHA bins.
# Reduced chi-squared = 0.7232 for 56 degrees of freedom
# Null hypothesis probability = 9.409184e-01
Photon flux (15-150 keV) in 128.7 sec: 7.80758E-02 ( -0.010367 0.0103804 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.21425e-07 ( -1.12905e-07 1.19098e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 90.184 sec. to 91.184 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.55475 ( -0.414946 0.396908 )
Norm@50keV : 3.62834E-03 ( -0.000961393 0.000942157 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 49.16 using 59 PHA bins.
# Reduced chi-squared = 0.8625 for 57 degrees of freedom
# Null hypothesis probability = 7.604141e-01
Photon flux (15-150 keV) in 1 sec: 0.459976 ( -0.113078 0.113166 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.41382e-08 ( -9.57019e-09 9.89903e-09 ) ergs/cm2
Cutoff power-law model
Time interval is from 90.184 sec. to 91.184 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.268648 ( -1.48401 2.57924 )
Epeak [keV] : 62.1642 ( -18.1379 -62.1642 )
Norm@50keV : 1.78182E-02 ( -0.0178182 0.410401 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 47.44 using 59 PHA bins.
# Reduced chi-squared = 0.8472 for 56 degrees of freedom
# Null hypothesis probability = 7.852857e-01
Photon flux (15-150 keV) in 1 sec: 0.441307 ( -0.115577 0.115816 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.08021e-08 ( -9.60971e-09 1.07392e-08 ) ergs/cm2
Time-resolved spectra
