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 -0.248 sec. to 108.028 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.40355 ( -0.0208045 0.020889 )
Norm@50keV : 9.07475E-02 ( -0.00114518 0.00114274 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 48.97 using 59 bins.
Reduced chi-squared = 0.859123
# Null hypothesis probability of 7.66e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 108.3 sec: 11.0605 ( -0.1704 0.171 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.49071e-05 ( -1.06698e-06 1.06799e-06 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.248 sec. to 108.028 sec.
Spectral model in the cutoff power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.24995 ( -0.0860046 0.0874716 )
Epeak [keV] : 327.218 ( -92.98 309.678 )
Norm@50keV : 0.103561 ( -0.00725648 0.00789908 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 39.66 using 59 bins.
Reduced chi-squared = 0.708214
# Null hypothesis probability of 9.52e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 108.3 sec: 10.8864 ( -0.1924 0.1938 ) ph/cm2/s
Energy fluence (15-150 keV) : 9.45167e-05 ( -1.08621e-06 1.08786e-06 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 0.952 sec. to 1.952 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.957149 ( -0.0316382 0.031768 )
Norm@50keV : 1.00258 ( -0.0185298 0.0184969 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 64.15 using 59 bins.
Reduced chi-squared = 1.12544
# Null hypothesis probability of 2.40e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 115.212 ( -2.169 2.172 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.10118e-05 ( -2.02191e-07 2.02444e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 0.952 sec. to 1.952 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.662 ( -0.131535 0.135256 )
Epeak [keV] : 286.165 ( -69.3822 170.702 )
Norm@50keV : 1.31820 ( -0.148166 0.171107 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 49.08 using 59 bins.
Reduced chi-squared = 0.876429
# Null hypothesis probability of 7.32e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 113.647 ( -2.256 2.261 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.08111e-06 ( -7.7876e-07 4.92324e-08 ) ergs/cm2
Time-resolved spectra
