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 -1.344 sec. to 296.912 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.51869 ( -0.120788 0.120014 )
Norm@50keV : 9.77123E-04 ( -6.81123e-05 6.77404e-05 )
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#Fit statistic : Chi-Squared = 52.24 using 59 PHA bins.
# Reduced chi-squared = 0.9165 for 57 degrees of freedom
# Null hypothesis probability = 6.538391e-01
Photon flux (15-150 keV) in 298.3 sec: 0.122610 ( -0.008276 0.008283 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.75717e-06 ( -2.11492e-07 2.13698e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.344 sec. to 296.912 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.29077 ( -0.291277 0.488258 )
Epeak [keV] : 150.299 ( -72.4834 -150.3 )
Norm@50keV : 1.28332E-03 ( -0.000361368 0.000981836 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 51.48 using 59 PHA bins.
# Reduced chi-squared = 0.9193 for 56 degrees of freedom
# Null hypothesis probability = 6.463191e-01
Photon flux (15-150 keV) in 298.3 sec: 0.121205 ( -0.008722 0.008705 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.69658e-06 ( -2.42077e-07 2.42379e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 160.356 sec. to 161.356 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.01167 ( -0.124083 0.125553 )
Norm@50keV : 2.17567E-02 ( -0.00153797 0.0015366 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 63.13 using 59 PHA bins.
# Reduced chi-squared = 1.108 for 57 degrees of freedom
# Null hypothesis probability = 2.686305e-01
Photon flux (15-150 keV) in 1 sec: 2.50643 ( -0.17932 0.17949 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.34326e-07 ( -1.86857e-08 1.88019e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 160.356 sec. to 161.356 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.913282 ( -0.1582 0.482285 )
Epeak [keV] : 625.590 ( -625.59 -625.59 )
Norm@50keV : 2.41234E-02 ( -0.00360537 0.0151456 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 62.99 using 59 PHA bins.
# Reduced chi-squared = 1.125 for 56 degrees of freedom
# Null hypothesis probability = 2.427356e-01
Photon flux (15-150 keV) in 1 sec: 0.666125 ( -0.252904 0.192767 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.33163e-07 ( -1.95784e-08 1.92897e-08 ) ergs/cm2
Time-resolved spectra
