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 -8.552 sec. to 41.704 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.81321 ( -0.184893 0.177818 )
Norm@50keV : 2.83835E-03 ( -0.000324843 0.000318725 )
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#Fit statistic : Chi-Squared 43.72 using 59 bins.
Reduced chi-squared = 0.767018
# Null hypothesis probability of 9.02e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 50.26 sec: 0.393161 ( -0.038906 0.038932 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.31293e-06 ( -1.51102e-07 1.53401e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -8.552 sec. to 41.704 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.40523 ( -0.669905 0.742023 )
Epeak [keV] : 67.0219 ( -19.6458 -67.0203 )
Norm@50keV : 4.71607E-03 ( -0.00186206 0.00696988 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 42.57 using 59 bins.
Reduced chi-squared = 0.760179
# Null hypothesis probability of 9.07e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 50.26 sec: 0.386332 ( -0.040362 0.040349 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.26804e-06 ( -1.64793e-07 1.68119e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from -0.068 sec. to 0.932 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.3188 ( -0.177109 0.175747 )
Norm@50keV : 2.77147E-02 ( -0.00297003 0.00296409 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 56.72 using 59 bins.
Reduced chi-squared = 0.995088
# Null hypothesis probability of 4.85e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 3.31820 ( -0.36172 0.36214 ) ph/cm2/s
Energy fluence (15-150 keV) : 2.72672e-07 ( -3.21914e-08 3.23422e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.068 sec. to 0.932 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.861265 ( -0.543093 0.786155 )
Epeak [keV] : 136.821 ( -55.76 -136.82 )
Norm@50keV : 4.55892E-02 ( -0.0198296 0.0580951 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 55.42 using 59 bins.
Reduced chi-squared = 0.989643
# Null hypothesis probability of 4.97e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 3.27346 ( -0.36879 0.36841 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.05604e-07 ( -3.64082e-08 3.28578e-08 ) ergs/cm2
Time-resolved spectra
