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 14.792 sec. to 68.152 sec.
Spectral model in power-law:
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Parameters : value lower 90% higher 90%
Photon index: -1.85637 ( -0.182555 0.175494 )
Norm@50keV : 3.41335E-03 ( -0.000407733 0.000400489 )
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#Fit statistic : Chi-Squared 61.39 using 59 bins.
Reduced chi-squared = 1.07702
# Null hypothesis probability of 3.22e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 53.36 sec: 0.481057 ( -0.048964 0.048982 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.67489e-06 ( -1.98212e-07 2.01122e-07 ) ergs/cm2
Cutoff power-law model
Time interval is from 14.792 sec. to 68.152 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.18433 ( -0.699248 0.840872 )
Epeak [keV] : 52.6424 ( -13.8972 -52.6424 )
Norm@50keV : 8.18551E-03 ( -0.00482337 0.0161387 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 58.73 using 59 bins.
Reduced chi-squared = 1.04875
# Null hypothesis probability of 3.76e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 53.36 sec: 0.470519 ( -0.05021 0.050205 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.57553e-06 ( -2.16697e-07 2.24568e-07 ) ergs/cm2
1-s peak spectrum fit
Power-law model
Time interval is from 14.812 sec. to 15.812 sec.
Spectral model in power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: -1.64085 ( -0.324437 0.305489 )
Norm@50keV : 1.43609E-02 ( -0.00313282 0.00309387 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 61.43 using 59 bins.
Reduced chi-squared = 1.07772
# Null hypothesis probability of 3.20e-01 with 57 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.86961 ( -0.39357 0.39439 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.33712e-07 ( -3.02526e-08 3.05322e-08 ) ergs/cm2
Cutoff power-law model
Time interval is from 14.812 sec. to 15.812 sec.
Spectral model in the cutoff power-law:
------------------------------------------------------------
Parameters : value lower 90% higher 90%
Photon index: 0.160401 ( -1.47259 2.24534 )
Epeak [keV] : 62.6202 ( -14.4123 50.5044 )
Norm@50keV : 0.109674 ( -0.109764 1.08715 )
------------------------------------------------------------
#Fit statistic : Chi-Squared 56.80 using 59 bins.
Reduced chi-squared = 1.01429
# Null hypothesis probability of 4.45e-01 with 56 degrees of freedom
Photon flux (15-150 keV) in 1 sec: 1.79118 ( -0.40895 0.40556 ) ph/cm2/s
Energy fluence (15-150 keV) : 1.28905e-07 ( -3.02225e-08 3.12056e-08 ) ergs/cm2
Time-resolved spectra
