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 3.784 sec. to 11.184 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.7276 ( -0.17918 0.172489 )
Norm@50keV : 3.35904E-03 ( -0.000388084 0.000381618 )
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#Fit statistic : Chi-Squared = 85.87 using 59 PHA bins.
# Reduced chi-squared = 1.507 for 57 degrees of freedom
# Null hypothesis probability = 8.015739e-03
Photon flux (15-150 keV) in 7.4 sec: 0.450526 ( -0.043928 0.04393 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.29716e-07 ( -2.74832e-08 2.80892e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 3.784 sec. to 11.184 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.767538 ( -0.763956 0.927762 )
Epeak [keV] : 55.1234 ( -11.291 49.188 )
Norm@50keV : 1.17077E-02 ( -0.00728107 0.027668 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 81.09 using 59 PHA bins.
# Reduced chi-squared = 1.448 for 56 degrees of freedom
# Null hypothesis probability = 1.584200e-02
Photon flux (15-150 keV) in 7.4 sec: 0.433398 ( -0.045528 0.045712 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.07191e-07 ( -3.00164e-08 3.23123e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 6.156 sec. to 7.156 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.68178 ( -0.209863 0.202266 )
Norm@50keV : 7.51033E-03 ( -0.00107067 0.00105455 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 61.19 using 59 PHA bins.
# Reduced chi-squared = 1.073 for 57 degrees of freedom
# Null hypothesis probability = 3.281119e-01
Photon flux (15-150 keV) in 1 sec: 0.991229 ( -0.122412 0.122411 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.96578e-08 ( -1.03653e-08 1.06208e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 6.156 sec. to 7.156 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.0341636 ( -1.0375 1.3931 )
Epeak [keV] : 49.2255 ( -8.65653 19.5185 )
Norm@50keV : 6.80462E-02 ( -0.0680545 0.396301 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 52.77 using 59 PHA bins.
# Reduced chi-squared = 0.9423 for 56 degrees of freedom
# Null hypothesis probability = 5.980254e-01
Photon flux (15-150 keV) in 1 sec: 0.944131 ( -0.123123 0.124109 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.90351e-08 ( -1.0354e-08 1.16536e-08 ) ergs/cm2
Time-resolved spectra