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 -4.456 sec. to 72.216 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.69699 ( -0.238552 0.232181 )
Norm@50keV : 2.95234E-03 ( -0.000409829 0.00040336 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 57.40 using 59 PHA bins.
# Reduced chi-squared = 1.007 for 57 degrees of freedom
# Null hypothesis probability = 4.601691e-01
Photon flux (15-150 keV) in 76.67 sec: 0.391708 ( -0.051586 0.05177 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.0966e-06 ( -3.02466e-07 3.06628e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -4.456 sec. to 72.216 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.48441 ( -0.443377 1.06342 )
Epeak [keV] : 116.353 ( -116.356 -116.356 )
Norm@50keV : 3.81404E-03 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 57.24 using 59 PHA bins.
# Reduced chi-squared = 1.022 for 56 degrees of freedom
# Null hypothesis probability = 4.287148e-01
Photon flux (15-150 keV) in 76.67 sec: 0.387709 ( -0.054508 0.053306 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.05933e-06 ( -3.42779e-07 3.33359e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from -2.404 sec. to -1.404 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.72763 ( -0.663056 0.59838 )
Norm@50keV : 9.55920E-03 ( -0.00362942 0.00345212 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.61 using 59 PHA bins.
# Reduced chi-squared = 0.8528 for 57 degrees of freedom
# Null hypothesis probability = 7.777975e-01
Photon flux (15-150 keV) in 1 sec: 1.28213 ( -0.448326 0.45131 ) ph/cm2/s
Energy fluence (15-150 keV) : 8.83426e-08 ( -3.31666e-08 3.40316e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -2.404 sec. to -1.404 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.24157 ( -0.900459 4.19795 )
Epeak [keV] : 75.5593 ( -75.6247 -75.6247 )
Norm@50keV : 1.71515E-02 ( -0.0171261 1.83895 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 48.52 using 59 PHA bins.
# Reduced chi-squared = 0.8664 for 56 degrees of freedom
# Null hypothesis probability = 7.509897e-01
Photon flux (15-150 keV) in 1 sec: 1.25919 ( -0.476078 0.45729 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.58688e-08 ( -1.50435e-08 5.58226e-08 ) ergs/cm2
Time-resolved spectra
