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 -0.536 sec. to 8.376 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.84416 ( -0.0800909 0.0790899 )
Norm@50keV : 1.87926E-02 ( -0.000878568 0.00087453 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 53.08 using 59 PHA bins.
# Reduced chi-squared = 0.9312 for 57 degrees of freedom
# Null hypothesis probability = 6.230034e-01
Photon flux (15-150 keV) in 8.912 sec: 2.63540 ( -0.12238 0.12267 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.54033e-06 ( -7.24028e-08 7.26336e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from -0.536 sec. to 8.376 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.29361 ( -0.337473 0.366627 )
Epeak [keV] : 61.8766 ( -9.26421 24.5389 )
Norm@50keV : 3.61368E-02 ( -0.0117173 0.0194173 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 44.96 using 59 PHA bins.
# Reduced chi-squared = 0.8029 for 56 degrees of freedom
# Null hypothesis probability = 8.545634e-01
Photon flux (15-150 keV) in 8.912 sec: 2.55482 ( -0.13102 0.13141 ) ph/cm2/s
Energy fluence (15-150 keV) : 0 ( 0 0 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 1.556 sec. to 2.556 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.6694 ( -0.114646 0.112971 )
Norm@50keV : 4.02942E-02 ( -0.00289238 0.0028778 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 91.72 using 59 PHA bins.
# Reduced chi-squared = 1.609 for 57 degrees of freedom
# Null hypothesis probability = 2.417836e-03
Photon flux (15-150 keV) in 1 sec: 5.29579 ( -0.37249 0.37294 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.74111e-07 ( -2.80999e-08 2.82446e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 1.556 sec. to 2.556 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -0.851897 ( -0.525392 0.604212 )
Epeak [keV] : 66.9895 ( -11.7911 36.9951 )
Norm@50keV : 0.108628 ( -0.0505174 0.116262 )
------------------------------------------------------------
#Fit statistic : Chi-Squared = 84.24 using 59 PHA bins.
# Reduced chi-squared = 1.504 for 56 degrees of freedom
# Null hypothesis probability = 8.674589e-03
Photon flux (15-150 keV) in 1 sec: 4.40546 ( -0.44189 0.47416 ) ph/cm2/s
Energy fluence (15-150 keV) : 3.54111e-07 ( -3.13434e-08 3.13319e-08 ) ergs/cm2
Time-resolved spectra
