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 -24.752 sec. to 58.204 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.71877 ( -0.13013 0.127256 )
Norm@50keV : 1.52465E-03 ( -0.000121361 0.000119971 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.07 using 59 PHA bins.
# Reduced chi-squared = 0.9310 for 57 degrees of freedom
# Null hypothesis probability = 6.233013e-01
Photon flux (15-150 keV) in 82.96 sec: 0.203846 ( -0.014245 0.014249 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.16963e-06 ( -9.72233e-08 9.87207e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -24.752 sec. to 58.204 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.09529 ( -0.507256 0.581077 )
Epeak [keV] : 65.0351 ( -14.1435 80.5721 )
Norm@50keV : 3.33995E-03 ( -0.00154588 0.00354594 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.52 using 59 PHA bins.
# Reduced chi-squared = 0.8664 for 56 degrees of freedom
# Null hypothesis probability = 7.510014e-01
Photon flux (15-150 keV) in 82.96 sec: 0.197629 ( -0.015055 0.015057 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.09423e-06 ( -1.1129e-07 1.14327e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.624 sec. to 1.624 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.70676 ( -0.40814 0.373793 )
Norm@50keV : 4.47972E-03 ( -0.00116422 0.00111349 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 68.96 using 59 PHA bins.
# Reduced chi-squared = 1.210 for 57 degrees of freedom
# Null hypothesis probability = 1.331063e-01
Photon flux (15-150 keV) in 1 sec: 0.596394 ( -0.125695 0.125703 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.14629e-08 ( -1.09116e-08 1.14218e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.624 sec. to 1.624 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.33483 ( -1.07114 1.99716 )
Epeak [keV] : 76.3689 ( -76.3249 -76.3689 )
Norm@50keV : 7.32874E-03 ( -0.00732874 0.102406 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 68.79 using 59 PHA bins.
# Reduced chi-squared = 1.228 for 56 degrees of freedom
# Null hypothesis probability = 1.172487e-01
Photon flux (15-150 keV) in 1 sec: 0.588502 ( -0.129571 0.1295 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.96333e-08 ( -1.23875e-08 1.28305e-08 ) ergs/cm2
Time-resolved spectra
