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 3.508 sec. to 149.612 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -2.18603 ( -0.209194 0.196776 )
Norm@50keV : 9.95853E-04 ( -0.000138913 0.000135769 )
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#Fit statistic : Chi-Squared = 68.58 using 59 PHA bins.
# Reduced chi-squared = 1.203 for 57 degrees of freedom
# Null hypothesis probability = 1.399735e-01
Photon flux (15-150 keV) in 146.1 sec: 0.163682 ( -0.016986 0.016996 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.36559e-06 ( -1.64237e-07 1.67368e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 3.508 sec. to 149.612 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.66344 ( -0.557941 0.949894 )
Epeak [keV] : 25.9700 ( -23.3909 17.7688 )
Norm@50keV : 2.02476E-03 ( -0.00124295 0.00540873 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 67.29 using 59 PHA bins.
# Reduced chi-squared = 1.202 for 56 degrees of freedom
# Null hypothesis probability = 1.435166e-01
Photon flux (15-150 keV) in 146.1 sec: 0.160473 ( -0.017628 0.017634 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.29712e-06 ( -1.84364e-07 1.92311e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 30.684 sec. to 31.684 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.5031 ( -0.634018 0.625211 )
Norm@50keV : 5.00191E-03 ( -0.0016913 0.00167326 )
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#Fit statistic : Chi-Squared = 53.48 using 59 PHA bins.
# Reduced chi-squared = 0.9382 for 57 degrees of freedom
# Null hypothesis probability = 6.080994e-01
Photon flux (15-150 keV) in 1 sec: 0.624971 ( -0.218258 0.220902 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.74329e-08 ( -1.6916e-08 1.72099e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 30.684 sec. to 31.684 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.20715 ( -1.32286 4.54204 )
Epeak [keV] : 145.114 ( -145.039 -145.039 )
Norm@50keV : 6.89846E-03 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.44 using 59 PHA bins.
# Reduced chi-squared = 0.9543 for 56 degrees of freedom
# Null hypothesis probability = 5.724276e-01
Photon flux (15-150 keV) in 1 sec: 0.615133 ( -0.254406 0.22637 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.67175e-08 ( -1.81179e-08 1.77484e-08 ) ergs/cm2
Time-resolved spectra