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 11.960 sec. to 88.780 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.4257 ( -0.272017 0.245422 )
Norm@50keV : 1.03667E-03 ( -0.000200566 0.000197202 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 56.59 using 59 bins.
Reduced chi-squared = 0.992807
# Null hypothesis probability of 4.91e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 76.82 sec: 0.194760 ( -0.022761 0.022761 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.81674e-07 ( -1.13877e-07 1.17956e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 11.960 sec. to 88.780 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.61098 ( -0.398179 1.41116 )
Epeak [keV] : 17.5623 ( -15.0695 14.6765 )
Norm@50keV : 3.33265E-03 ( -0.00180141 0.0228322 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 55.04 using 59 bins.
Reduced chi-squared = 0.982857
# Null hypothesis probability of 5.11e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 76.82 sec: 0.189889 ( -0.023447 0.023577 ) ph/cm2/s
Energy fluence (15-150 keV) : 7.2416e-07 ( -1.18743e-07 1.32097e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 47.972 sec. to 48.972 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.87677 ( -0.483855 0.436885 )
Norm@50keV : 5.77815E-03 ( -0.00170785 0.0015984 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 76.21 using 59 bins.
Reduced chi-squared = 1.33702
# Null hypothesis probability of 4.55e-02 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.821217 ( -0.192549 0.192673 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.31276e-08 ( -1.48134e-08 1.52935e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 47.972 sec. to 48.972 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.26113 ( -0.483741 0.598576 )
Epeak [keV] : 100.789 ( -9999.32 -9999.33 )
Norm@50keV : 3.56048E-03 ( -0.00167181 0.026067 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 75.78 using 59 bins.
Reduced chi-squared = 1.35321
# Null hypothesis probability of 4.03e-02 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.665916 ( -0.29162 0.475754 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.8463e-08 ( -2.09435e-08 1.51169e-08 ) ergs/cm2
Time-resolved spectra
