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 -1.340 sec. to 318.884 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.23652 ( -0.239354 0.241628 )
Norm@50keV : 4.38081E-04 ( -5.88908e-05 5.87693e-05 )
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#Fit statistic : Chi-Squared = 56.59 using 59 PHA bins.
# Reduced chi-squared = 0.9928 for 57 degrees of freedom
# Null hypothesis probability = 4.903321e-01
Photon flux (15-150 keV) in 320.2 sec: 5.17021E-02 ( -0.0069781 0.0069889 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.40903e-06 ( -2.16965e-07 2.20605e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.340 sec. to 318.884 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.982891 ( -0.479816 1.0787 )
Epeak [keV] : 209.063 ( -209.058 -209.058 )
Norm@50keV : 5.82383E-04 ( -0.000198532 0.00126255 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.37 using 59 PHA bins.
# Reduced chi-squared = 1.007 for 56 degrees of freedom
# Null hypothesis probability = 4.611326e-01
Photon flux (15-150 keV) in 320.2 sec: 5.10696E-02 ( -0.0073832 0.0073118 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.38016e-06 ( -2.41381e-07 2.3617e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.116 sec. to 1.116 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.2443 ( -0.536156 0.548423 )
Norm@50keV : 4.40228E-03 ( -0.00122621 0.00120627 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 65.35 using 59 PHA bins.
# Reduced chi-squared = 1.147 for 57 degrees of freedom
# Null hypothesis probability = 2.093578e-01
Photon flux (15-150 keV) in 1 sec: 0.520194 ( -0.141873 0.142139 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.41296e-08 ( -1.41739e-08 1.46897e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.116 sec. to 1.116 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.25653 ( -0.524904 0.863628 )
Epeak [keV] : 9999.36 ( -9999.36 -9999.36 )
Norm@50keV : 4.38886E-03 ( -0.00122885 0.0126858 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 65.36 using 59 PHA bins.
# Reduced chi-squared = 1.167 for 56 degrees of freedom
# Null hypothesis probability = 1.836077e-01
Photon flux (15-150 keV) in 1 sec: 0.520109 ( -0.14201 0.142074 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.43803e-08 ( -1.76533e-08 7.31844e-09 ) ergs/cm2
Time-resolved spectra
