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 1.672 sec. to 109.928 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.28852 ( -0.122012 0.123997 )
Norm@50keV : 7.12160E-03 ( -0.000483912 0.000481461 )
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#Fit statistic : Chi-Squared 60.19 using 59 bins.
Reduced chi-squared = 1.05596
# Null hypothesis probability of 3.61e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 108.3 sec: 0.847863 ( -0.064567 0.06511 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.64397e-06 ( -5.09057e-07 5.09804e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.672 sec. to 109.928 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.28421 ( -0.167 0.327984 )
Epeak [keV] : 9999.35 ( -9999.35 -9999.35 )
Norm@50keV : 7.15190E-03 ( -0.000477502 0.00274007 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 60.21 using 59 bins.
Reduced chi-squared = 1.07518
# Null hypothesis probability of 3.26e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 108.3 sec: 0.847607 ( -0.064536 0.065149 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.64273e-06 ( -5.09465e-07 5.09725e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 24.492 sec. to 25.492 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.19259 ( -0.496851 0.392449 )
Norm@50keV : 1.27440E-02 ( -0.00473318 0.00464407 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 64.00 using 59 bins.
Reduced chi-squared = 1.12281
# Null hypothesis probability of 2.44e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 2.09981 ( -0.7433 0.75066 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.19795e-07 ( -4.18999e-08 4.20428e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 24.492 sec. to 25.492 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.2103 ( -2.10921 3.92253 )
Epeak [keV] : 61.6796 ( -16.7419 14.3066 )
Norm@50keV : 0.348611 ( -0.348318 5.48829 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 55.60 using 59 bins.
Reduced chi-squared = 0.992857
# Null hypothesis probability of 4.90e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.99183 ( -0.70555 0.7431 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.50439e-07 ( -4.57117e-08 4.55583e-08 ) ergs/cm2
Time-resolved spectra
