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 -1.492 sec. to 773.032 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.21193 ( -0.0453108 0.0455391 )
Norm@50keV : 2.56990E-03 ( -6.08443e-05 6.07313e-05 )
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#Fit statistic : Chi-Squared = 54.43 using 59 PHA bins.
# Reduced chi-squared = 0.9549 for 57 degrees of freedom
# Null hypothesis probability = 5.721771e-01
Photon flux (15-150 keV) in 774.5 sec: 0.302172 ( -0.007807 0.00784 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.0128e-05 ( -4.89376e-07 4.90216e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -1.492 sec. to 773.032 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.20944 ( -0.0437552 0.0478891 )
Epeak [keV] : 9999.36 ( -9999.36 -9999.36 )
Norm@50keV : 2.58082E-03 ( -6.05887e-05 0.000235772 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 54.54 using 59 PHA bins.
# Reduced chi-squared = 0.9739 for 56 degrees of freedom
# Null hypothesis probability = 5.302476e-01
Photon flux (15-150 keV) in 774.5 sec: 0.304470 ( -0.010203 0.005433 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.02279e-05 ( -5.95164e-07 3.8366e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 15.972 sec. to 16.972 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.0695 ( -0.0972536 0.0977638 )
Norm@50keV : 5.48944E-02 ( -0.00297656 0.00297655 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 42.62 using 59 PHA bins.
# Reduced chi-squared = 0.7477 for 57 degrees of freedom
# Null hypothesis probability = 9.217109e-01
Photon flux (15-150 keV) in 1 sec: 0.299354 ( ) ph/cm2/s
Energy fluence (15-150 keV) : 5.79709e-07 ( -3.63211e-08 3.6517e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 15.972 sec. to 16.972 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.06432 ( -0.235603 0.328591 )
Epeak [keV] : 9998.11 ( -9998.02 -9998.02 )
Norm@50keV : 5.52024E-02 ( -0.00299326 0.0274489 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 42.61 using 59 PHA bins.
# Reduced chi-squared = 0.7609 for 56 degrees of freedom
# Null hypothesis probability = 9.063104e-01
Photon flux (15-150 keV) in 1 sec: 6.34267 ( -0.35024 0.36289 ) ph/cm2/s
Energy fluence (15-150 keV) : 5.78709e-07 ( -3.99928e-08 3.84968e-08 ) ergs/cm2
Time-resolved spectra