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 -0.700 sec. to 515.344 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.26024 ( -0.430438 0.447912 )
Norm@50keV : 2.02674E-04 ( -5.16483e-05 5.16477e-05 )
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#Fit statistic : Chi-Squared 75.87 using 59 bins.
Reduced chi-squared = 1.33105
# Null hypothesis probability of 4.80e-02 with 57 degrees of freedom
Photon flux (15-150 keV) in 516 sec: 2.40116E-02 ( -0.0063166 0.0063667 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.04395e-06 ( -2.87101e-07 2.9289e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.700 sec. to 515.344 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.00671053 ( -1.11867 3.59608 )
Epeak [keV] : 83.5282 ( -31.1791 -83.5281 )
Norm@50keV : 8.03397E-04 ( -0.0008034 0.0286119 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 74.68 using 59 bins.
Reduced chi-squared = 1.33357
# Null hypothesis probability of 4.83e-02 with 56 degrees of freedom
Photon flux (15-150 keV) in 516 sec: 2.26189E-02 ( -0.0068623 0.0067549 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.56974e-07 ( -3.07906e-07 3.2394e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 4.280 sec. to 5.280 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.25223 ( -0.275718 0.281164 )
Norm@50keV : 8.75462E-03 ( -0.00137561 0.00137392 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 46.84 using 59 bins.
Reduced chi-squared = 0.821754
# Null hypothesis probability of 8.29e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.03582 ( -0.166569 0.16703 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.7575e-08 ( -1.53013e-08 1.55063e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 4.280 sec. to 5.280 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.964943 ( -1.09469 1.30084 )
Epeak [keV] : 187.198 ( -187.233 -187.233 )
Norm@50keV : 1.21137E-02 ( -0.00462884 0.0382054 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 46.63 using 59 bins.
Reduced chi-squared = 0.832679
# Null hypothesis probability of 8.10e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.02296 ( -0.17406 0.17304 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.13466e-08 ( -7.69176e-09 8.07915e-09 ) ergs/cm2
Time-resolved spectra
