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 1.388 sec. to 10.996 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.54418 ( -0.308104 0.298578 )
Norm@50keV : 1.93043E-03 ( -0.000373888 0.000368562 )
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#Fit statistic : Chi-Squared = 79.51 using 59 PHA bins.
# Reduced chi-squared = 1.395 for 57 degrees of freedom
# Null hypothesis probability = 2.609332e-02
Photon flux (15-150 keV) in 9.608 sec: 0.243979 ( -0.044625 0.044673 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.74776e-07 ( -3.62465e-08 3.70516e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.388 sec. to 10.996 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.535428 ( -1.10946 1.47587 )
Epeak [keV] : 70.8304 ( -21.1614 -70.8599 )
Norm@50keV : 6.40147E-03 ( -0.00639359 0.0284932 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 77.15 using 59 PHA bins.
# Reduced chi-squared = 1.378 for 56 degrees of freedom
# Null hypothesis probability = 3.201037e-02
Photon flux (15-150 keV) in 9.608 sec: 0.235621 ( -0.045505 0.045589 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.63532e-07 ( -3.69876e-08 3.88551e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 1.440 sec. to 2.440 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.50821 ( -0.455726 0.432223 )
Norm@50keV : 4.02066E-03 ( -0.00117095 0.00115388 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 87.71 using 59 PHA bins.
# Reduced chi-squared = 1.539 for 57 degrees of freedom
# Null hypothesis probability = 5.562921e-03
Photon flux (15-150 keV) in 1 sec: 0.503057 ( -0.140247 0.140581 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.80996e-08 ( -1.17678e-08 1.21404e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.440 sec. to 2.440 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 1.18268 ( -2.5048 -1.33738 )
Epeak [keV] : 60.6096 ( -13.5889 63.7545 )
Norm@50keV : 8.09564E-02 ( -0.104353 987.012 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 83.71 using 59 PHA bins.
# Reduced chi-squared = 1.495 for 56 degrees of freedom
# Null hypothesis probability = 9.631324e-03
Photon flux (15-150 keV) in 1 sec: 0.449386 ( -0.195661 0.153279 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.35606e-08 ( -1.27459e-08 1.23159e-08 ) ergs/cm2
Time-resolved spectra
