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 0.052 sec. to 25.688 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.99585 ( -0.252487 0.235874 )
Norm@50keV : 1.30627E-03 ( -0.000215471 0.000208924 )
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#Fit statistic : Chi-Squared = 56.82 using 59 PHA bins.
# Reduced chi-squared = 0.9968 for 57 degrees of freedom
# Null hypothesis probability = 4.818199e-01
Photon flux (15-150 keV) in 25.64 sec: 0.195581 ( -0.023364 0.023365 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.08849e-07 ( -4.67848e-08 4.83973e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.052 sec. to 25.688 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.0346 ( -0.0947001 1.11202 )
Epeak [keV] : 36.0634 ( )
Norm@50keV : 1.23899E-03 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 56.81 using 59 PHA bins.
# Reduced chi-squared = 1.015 for 56 degrees of freedom
# Null hypothesis probability = 4.444954e-01
Photon flux (15-150 keV) in 25.64 sec: 0.195922 ( -0.0243 0.02351 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.10554e-07 ( -6.07914e-08 4.07699e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.052 sec. to 1.052 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.37957 ( -0.158144 0.157736 )
Norm@50keV : 1.21129E-02 ( -0.00111622 0.00111276 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 63.33 using 59 PHA bins.
# Reduced chi-squared = 1.111 for 57 degrees of freedom
# Null hypothesis probability = 2.629614e-01
Photon flux (15-150 keV) in 1 sec: 1.46845 ( -0.13515 0.13528 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.17557e-07 ( -1.20867e-08 1.22117e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.052 sec. to 1.052 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.10627 ( -0.355672 0.668448 )
Epeak [keV] : 167.063 ( -167.063 -167.063 )
Norm@50keV : 1.65875E-02 ( -0.00541676 0.0182193 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 62.72 using 59 PHA bins.
# Reduced chi-squared = 1.120 for 56 degrees of freedom
# Null hypothesis probability = 2.501947e-01
Photon flux (15-150 keV) in 1 sec: 1.45201 ( -0.14039 0.13983 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.15239e-07 ( -1.32226e-08 1.31773e-08 ) ergs/cm2
Time-resolved spectra
