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 -21.304 sec. to 160.136 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.47066 ( -0.191135 0.18924 )
Norm@50keV : 8.73005E-04 ( -9.80937e-05 9.75057e-05 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 48.10 using 59 bins.
Reduced chi-squared = 0.84386
# Null hypothesis probability of 7.93e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 181.4 sec: 0.108151 ( -0.0119674 0.011983 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.51e-06 ( -1.8643e-07 1.88545e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -21.304 sec. to 160.136 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.963259 ( -0.637882 0.923551 )
Epeak [keV] : 101.999 ( -37.8818 -101.999 )
Norm@50keV : 1.57717E-03 ( -0.000771777 0.00274121 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 46.79 using 59 bins.
Reduced chi-squared = 0.835536
# Null hypothesis probability of 8.05e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 181.4 sec: 0.105752 ( -0.0124863 0.012505 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.45217e-06 ( -2.05454e-07 2.0691e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 21.020 sec. to 22.020 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.11944 ( -0.933715 0.678538 )
Norm@50keV : 3.16189E-03 ( -0.0017101 0.00150599 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 61.87 using 59 bins.
Reduced chi-squared = 1.08544
# Null hypothesis probability of 3.06e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.502319 ( -0.169728 0.169737 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.94408e-08 ( -1.26493e-08 1.36416e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 21.020 sec. to 22.020 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -2.89151 ( -0.333503 3.78773 )
Epeak [keV] : 281.185 ( )
Norm@50keV : 1.33891E-03 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared 61.61 using 59 bins.
Reduced chi-squared = 1.10018
# Null hypothesis probability of 2.82e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 0.384059 ( -0.207679 0.281689 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.98119e-08 ( -1.01842e-08 1.1395e-08 ) ergs/cm2
Time-resolved spectra
