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 -44.432 sec. to 13.616 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.39779 ( -0.287202 0.289722 )
Norm@50keV : 2.24462E-03 ( -0.000395816 0.00039519 )
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#Fit statistic : Chi-Squared 56.15 using 59 bins.
Reduced chi-squared = 0.985088
# Null hypothesis probability of 5.07e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 58.05 sec: 0.273221 ( -0.049403 0.049618 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.25977e-06 ( -2.39133e-07 2.41925e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -44.432 sec. to 13.616 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.140129 ( -1.30002 1.89508 )
Epeak [keV] : 73.9019 ( -20.6072 -73.9018 )
Norm@50keV : 9.61273E-03 ( -0.00961279 0.0712921 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 53.47 using 59 bins.
Reduced chi-squared = 0.954821
# Null hypothesis probability of 5.71e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 58.05 sec: 0.260139 ( -0.051644 0.051674 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.15431e-06 ( -2.5937e-07 2.68258e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.412 sec. to 1.412 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.29081 ( -0.373185 0.384326 )
Norm@50keV : 1.42338E-02 ( -0.0031852 0.00318007 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 68.18 using 59 bins.
Reduced chi-squared = 1.19614
# Null hypothesis probability of 1.48e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.69531 ( -0.40186 0.40539 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.40991e-07 ( -3.29621e-08 3.30935e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.412 sec. to 1.412 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.635939 ( -0.912899 2.3029 )
Epeak [keV] : 116.556 ( -116.546 -116.546 )
Norm@50keV : 2.84916E-02 ( -0.0170574 0.255268 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 67.76 using 59 bins.
Reduced chi-squared = 1.21
# Null hypothesis probability of 1.35e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.65476 ( -0.4099 0.41883 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.37749e-07 ( -2.05403e-08 3.44339e-08 ) ergs/cm2
Time-resolved spectra
