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
Multiple GTIs in the spectrum
tstart tstop
-27.360000 233.744000
235.024000 855.488000
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.38916 ( -0.0376513 0.0377154 )
Norm@50keV : 2.74202E-03 ( -5.28932e-05 5.28642e-05 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 41.14 using 59 PHA bins.
# Reduced chi-squared = 0.7217 for 57 degrees of freedom
# Null hypothesis probability = 9.437783e-01
Photon flux (15-150 keV) in 881.6 sec: 0.333120 ( -0.007318 0.007344 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.34133e-05 ( -4.64384e-07 4.64931e-07 ) ergs/cm2
Cutoff power-law model
Multiple GTIs in the spectrum
tstart tstop
-27.360000 233.744000
235.024000 855.488000
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.25175 ( -0.0671064 0.152262 )
Epeak [keV] : 315.802 ( -134.431 -315.799 )
Norm@50keV : 3.14271E-03 ( -0.000408901 0.000497663 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 38.62 using 59 PHA bins.
# Reduced chi-squared = 0.6896 for 56 degrees of freedom
# Null hypothesis probability = 9.630203e-01
Photon flux (15-150 keV) in 881.6 sec: 0.329218 ( -0.008326 0.008371 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.32082e-05 ( -5.13658e-07 5.12715e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 646.612 sec. to 647.612 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.26216 ( -0.0918243 0.0918341 )
Norm@50keV : 3.19602E-02 ( -0.001688 0.00168611 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.48 using 59 PHA bins.
# Reduced chi-squared = 1.026 for 57 degrees of freedom
# Null hypothesis probability = 4.209157e-01
Photon flux (15-150 keV) in 1 sec: 3.78766 ( -0.2018 0.2019 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.18882e-07 ( -1.91452e-08 1.92529e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 646.612 sec. to 647.612 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.945692 ( -0.343957 0.378414 )
Epeak [keV] : 175.264 ( -68.2901 -175.264 )
Norm@50keV : 4.55089E-02 ( -0.0140209 0.0230671 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.07 using 59 PHA bins.
# Reduced chi-squared = 1.001 for 56 degrees of freedom
# Null hypothesis probability = 4.720617e-01
Photon flux (15-150 keV) in 1 sec: 3.73494 ( -0.21013 0.20989 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.11774e-07 ( -2.09234e-08 2.08396e-08 ) ergs/cm2
Time-resolved spectra
