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 -1.088 sec. to 12.400 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.28988 ( -0.278839 0.28219 )
Norm@50keV : 1.97766E-03 ( -0.00032393 0.000323062 )
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#Fit statistic : Chi-Squared 51.45 using 59 bins.
Reduced chi-squared = 0.902632
# Null hypothesis probability of 6.82e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 13.49 sec: 0.235509 ( -0.039312 0.039413 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.64322e-07 ( -4.77549e-08 4.8338e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.088 sec. to 12.400 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.697536 ( -0.807222 1.34203 )
Epeak [keV] : 118.266 ( -50.2251 -118.286 )
Norm@50keV : 3.77723E-03 ( -0.00205244 0.0110186 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 50.54 using 59 bins.
Reduced chi-squared = 0.9025
# Null hypothesis probability of 6.81e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 13.49 sec: 0.229636 ( -0.041074 0.04085 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.55565e-07 ( -5.02782e-08 5.0851e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 1.240 sec. to 2.240 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.31522 ( -0.491387 0.490744 )
Norm@50keV : 4.08154E-03 ( -0.00119553 0.00119343 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 64.06 using 59 bins.
Reduced chi-squared = 1.12386
# Null hypothesis probability of 2.43e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.488336 ( -0.145307 0.145971 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.01902e-08 ( -1.28054e-08 1.30562e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.240 sec. to 2.240 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.0695244 ( -1.74954 3.67666 )
Epeak [keV] : 82.0296 ( -57.9045 -82.0141 )
Norm@50keV : 1.78101E-02 ( -0.0178256 0.541714 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 62.91 using 59 bins.
Reduced chi-squared = 1.12339
# Null hypothesis probability of 2.45e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.462225 ( -0.154229 0.152935 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.79193e-08 ( -1.27952e-08 1.35632e-08 ) ergs/cm2
Time-resolved spectra
