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 -60.320 sec. to 51.288 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.34995 ( -0.160449 0.152573 )
Norm@50keV : 1.84352E-03 ( -0.000201947 0.000199364 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.86 using 59 PHA bins.
# Reduced chi-squared = 1.033 for 57 degrees of freedom
# Null hypothesis probability = 4.073353e-01
Photon flux (15-150 keV) in 111.6 sec: 0.331408 ( -0.024465 0.024476 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.9857e-06 ( -1.72588e-07 1.75995e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -60.320 sec. to 51.288 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.82421 ( -0.172355 0.693775 )
Epeak [keV] : 12.7522 ( -12.0718 16.2469 )
Norm@50keV : 3.84460E-03 ( -0.00123178 0.00634323 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.51 using 59 PHA bins.
# Reduced chi-squared = 1.009 for 56 degrees of freedom
# Null hypothesis probability = 4.558587e-01
Photon flux (15-150 keV) in 111.6 sec: 0.324165 ( -0.025645 0.025386 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.87635e-06 ( -1.98344e-07 2.03843e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from -0.536 sec. to 0.464 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.33374 ( -0.336645 0.337271 )
Norm@50keV : 1.07599E-02 ( -0.00195449 0.00194979 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.58 using 59 PHA bins.
# Reduced chi-squared = 0.9399 for 57 degrees of freedom
# Null hypothesis probability = 6.043442e-01
Photon flux (15-150 keV) in 1 sec: 1.29202 ( -0.24096 0.2416 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.05492e-07 ( -2.13234e-08 2.15449e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.536 sec. to 0.464 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.33639 ( -0.332631 0.57339 )
Epeak [keV] : 9999.19 ( -9999.34 -9999.34 )
Norm@50keV : 1.07977E-02 ( -0.00196177 0.0183158 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.58 using 59 PHA bins.
# Reduced chi-squared = 0.9568 for 56 degrees of freedom
# Null hypothesis probability = 5.669203e-01
Photon flux (15-150 keV) in 1 sec: 1.30193 ( ) ph/cm2/s
Energy fluence (15-150 keV) : 1.05996e-07 ( -2.51832e-08 2.44948e-08 ) ergs/cm2
Time-resolved spectra