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 -0.696 sec. to 69.192 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.44417 ( -0.140075 0.140017 )
Norm@50keV : 1.93171E-03 ( -0.000155657 0.000155207 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.47 using 59 PHA bins.
# Reduced chi-squared = 0.9381 for 57 degrees of freedom
# Null hypothesis probability = 6.081753e-01
Photon flux (15-150 keV) in 69.89 sec: 0.237720 ( -0.019683 0.019725 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.29347e-06 ( -1.13161e-07 1.13988e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.696 sec. to 69.192 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.17027 ( -0.345673 0.583336 )
Epeak [keV] : 156.640 ( -156.64 -156.64 )
Norm@50keV : 2.63620E-03 ( -0.000826193 0.00237853 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 52.68 using 59 PHA bins.
# Reduced chi-squared = 0.9407 for 56 degrees of freedom
# Null hypothesis probability = 6.013542e-01
Photon flux (15-150 keV) in 69.89 sec: 0.234775 ( -0.020489 0.020482 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.26989e-06 ( -1.23385e-07 1.2242e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.716 sec. to 1.716 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.1268 ( -0.172322 0.175161 )
Norm@50keV : 1.66587E-02 ( -0.00175923 0.00175748 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 63.73 using 59 PHA bins.
# Reduced chi-squared = 1.118 for 57 degrees of freedom
# Null hypothesis probability = 2.518553e-01
Photon flux (15-150 keV) in 1 sec: 1.93763 ( -0.21104 0.2116 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.72727e-07 ( -1.9523e-08 1.96132e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.716 sec. to 1.716 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.272777 ( -0.717645 0.864043 )
Epeak [keV] : 115.451 ( -32.4167 260.725 )
Norm@50keV : 4.02482E-02 ( -0.0207147 0.0531823 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 59.48 using 59 PHA bins.
# Reduced chi-squared = 1.062 for 56 degrees of freedom
# Null hypothesis probability = 3.501595e-01
Photon flux (15-150 keV) in 1 sec: 1.87900 ( -0.21692 0.21732 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.67275e-07 ( -2.06527e-08 2.05399e-08 ) ergs/cm2
Time-resolved spectra