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 -2.860 sec. to 36.480 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.79834 ( -0.213872 0.205208 )
Norm@50keV : 1.67305E-03 ( -0.000220207 0.000214682 )
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#Fit statistic : Chi-Squared = 41.74 using 59 PHA bins.
# Reduced chi-squared = 0.7323 for 57 degrees of freedom
# Null hypothesis probability = 9.354084e-01
Photon flux (15-150 keV) in 39.34 sec: 0.230407 ( -0.025627 0.025641 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.06056e-07 ( -8.03366e-08 8.17945e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -2.860 sec. to 36.480 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.80469 ( -0.210769 0.727598 )
Epeak [keV] : 9999.36 ( -9999.35 -9999.36 )
Norm@50keV : 1.66811E-03 ( -0.000761685 0.00248608 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 41.74 using 59 PHA bins.
# Reduced chi-squared = 0.7454 for 56 degrees of freedom
# Null hypothesis probability = 9.218283e-01
Photon flux (15-150 keV) in 39.34 sec: 0.231003 ( -0.027922 0.026414 ) ph/cm2/s
Energy fluence (15-150 keV) : 6.10344e-07 ( -1.03057e-07 6.31816e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 5.800 sec. to 6.800 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.92374 ( -0.642354 0.53639 )
Norm@50keV : 4.09380E-03 ( -0.00155178 0.00138386 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 59.36 using 59 PHA bins.
# Reduced chi-squared = 1.041 for 57 degrees of freedom
# Null hypothesis probability = 3.897269e-01
Photon flux (15-150 keV) in 1 sec: 0.593554 ( -0.159885 0.159891 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.76556e-08 ( -1.27217e-08 1.32658e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 5.800 sec. to 6.800 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -3.41212 ( -0.46828 1.97106 )
Epeak [keV] : 380.842 ( )
Norm@50keV : 7.98873E-04 ( )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 57.52 using 59 PHA bins.
# Reduced chi-squared = 1.027 for 56 degrees of freedom
# Null hypothesis probability = 4.186935e-01
Photon flux (15-150 keV) in 1 sec: 0.499182 ( -0.257657 0.237849 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.3655e-08 ( -1.72744e-08 1.31821e-08 ) ergs/cm2
Time-resolved spectra