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 -28.656 sec. to 127.388 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.08642 ( -0.14655 0.140826 )
Norm@50keV : 1.01081E-03 ( -9.85773e-05 9.70878e-05 )
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#Fit statistic : Chi-Squared = 59.43 using 59 PHA bins.
# Reduced chi-squared = 1.043 for 57 degrees of freedom
# Null hypothesis probability = 3.870278e-01
Photon flux (15-150 keV) in 156 sec: 0.157982 ( -0.011634 0.011637 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.46347e-06 ( -1.28707e-07 1.31028e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -28.656 sec. to 127.388 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.51611 ( -0.486524 0.633236 )
Epeak [keV] : 34.0586 ( -28.5271 13.2882 )
Norm@50keV : 2.19457E-03 ( -0.00101245 0.00301218 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.15 using 59 PHA bins.
# Reduced chi-squared = 1.003 for 56 degrees of freedom
# Null hypothesis probability = 4.693750e-01
Photon flux (15-150 keV) in 156 sec: 0.154279 ( -0.012094 0.012109 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.37285e-06 ( -1.47379e-07 1.53602e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.064 sec. to 1.064 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.19794 ( -0.265118 0.277639 )
Norm@50keV : 9.17367E-03 ( -0.00130445 0.00130125 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 67.54 using 59 PHA bins.
# Reduced chi-squared = 1.185 for 57 degrees of freedom
# Null hypothesis probability = 1.602513e-01
Photon flux (15-150 keV) in 1 sec: 1.07650 ( -0.159918 0.16058 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.31344e-08 ( -1.45367e-08 1.46411e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.064 sec. to 1.064 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.21128 ( -0.251231 0.296035 )
Epeak [keV] : 9999.36 ( -9999.36 -9999.36 )
Norm@50keV : 9.21875E-03 ( -0.00130564 0.00130615 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 67.57 using 59 PHA bins.
# Reduced chi-squared = 1.207 for 56 degrees of freedom
# Null hypothesis probability = 1.382179e-01
Photon flux (15-150 keV) in 1 sec: 1.08038 ( -0.169504 0.16168 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.81546e-08 ( -7.0416e-09 5.90974e-09 ) ergs/cm2
Time-resolved spectra
