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 -19.360 sec. to 7.104 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.47705 ( -0.114325 0.11344 )
Norm@50keV : 3.99458E-03 ( -0.000269937 0.000268798 )
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#Fit statistic : Chi-Squared 63.73 using 59 bins.
Reduced chi-squared = 1.11807
# Null hypothesis probability of 2.52e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 26.46 sec: 0.495678 ( -0.03255 0.032573 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.0067e-06 ( -7.53351e-08 7.60791e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -19.360 sec. to 7.104 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -0.73652 ( -0.487048 0.552903 )
Epeak [keV] : 82.5220 ( -17.4804 64.4651 )
Norm@50keV : 9.62503E-03 ( -0.00415399 0.00872724 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 56.59 using 59 bins.
Reduced chi-squared = 1.01054
# Null hypothesis probability of 4.53e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 26.46 sec: 0.478293 ( -0.034464 0.03443 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.41045e-07 ( -8.5742e-08 8.68057e-08 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.220 sec. to 1.220 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.40289 ( -0.169199 0.168271 )
Norm@50keV : 1.36618E-02 ( -0.00153781 0.00153151 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 74.59 using 59 bins.
Reduced chi-squared = 1.3086
# Null hypothesis probability of 5.89e-02 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.66490 ( -0.18193 0.182 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.31941e-07 ( -1.63936e-08 1.66149e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.220 sec. to 1.220 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.755416 ( -1.01545 1.34676 )
Epeak [keV] : 56.6132 ( -8.42759 15.0279 )
Norm@50keV : 0.210544 ( -0.210856 0.992786 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 57.70 using 59 bins.
Reduced chi-squared = 1.03036
# Null hypothesis probability of 4.12e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.56315 ( -0.18484 0.1862 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.08883e-07 ( -1.68741e-08 1.8479e-08 ) ergs/cm2
Time-resolved spectra
