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 -2.900 sec. to 178.516 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.7308 ( -0.126449 0.123702 )
Norm@50keV : 1.13137E-03 ( -8.67424e-05 8.58899e-05 )
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#Fit statistic : Chi-Squared = 54.71 using 59 PHA bins.
# Reduced chi-squared = 0.9598 for 57 degrees of freedom
# Null hypothesis probability = 5.614484e-01
Photon flux (15-150 keV) in 181.4 sec: 0.151918 ( -0.010511 0.01052 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.89626e-06 ( -1.51056e-07 1.52996e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from -2.900 sec. to 178.516 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.737271 ( -0.593732 0.689956 )
Epeak [keV] : 57.7805 ( -8.74693 21.7011 )
Norm@50keV : 3.86386E-03 ( -0.00198444 0.00514088 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 45.84 using 59 PHA bins.
# Reduced chi-squared = 0.8185 for 56 degrees of freedom
# Null hypothesis probability = 8.318219e-01
Photon flux (15-150 keV) in 181.4 sec: 0.144351 ( -0.011358 0.011364 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.7242e-06 ( -1.71249e-07 1.78401e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 27.640 sec. to 28.640 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.0572 ( -0.47904 0.531931 )
Norm@50keV : 4.55356E-03 ( -0.00118537 0.00117192 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.68 using 59 PHA bins.
# Reduced chi-squared = 1.030 for 57 degrees of freedom
# Null hypothesis probability = 4.135429e-01
Photon flux (15-150 keV) in 1 sec: 0.526207 ( -0.139686 0.140224 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.82848e-08 ( -1.35927e-08 1.38007e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 27.640 sec. to 28.640 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.06256 ( -0.472666 0.54576 )
Epeak [keV] : 9999.36 ( -9999.36 -9999.36 )
Norm@50keV : 4.58190E-03 ( -0.00117029 0.0128067 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 58.69 using 59 PHA bins.
# Reduced chi-squared = 1.048 for 56 degrees of freedom
# Null hypothesis probability = 3.770737e-01
Photon flux (15-150 keV) in 1 sec: 0.531776 ( -0.174259 0.163824 ) ph/cm2/s
Energy fluence (15-150 keV) : 4.85333e-08 ( -1.62766e-08 1.60619e-08 ) ergs/cm2
Time-resolved spectra
