The Input Energy vs. Output Energy.
The energy of input photon is between 5 keV and 500 keV, and the spectrum shape is the flat powerlaw, which is the photon index is 0.0. Also the input region is 600 [cm] x 600 [cm] and the number of input photon is 100 million, so the flux is ~278 [photons/cm^2] in this simulation.
Then the input energy bin is binned by 50 bins with the log scale, while the output energy bin is the same as the BAT ebounds for 80 bins (bat_ebounds80-2003-08-19.fits).
Here is the response matrix image. Y-axis shows the input energy bin, and X-axis shows the output energy bin.
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Here is the light curve in the SGR 806-02 events.
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A foreground PHA file is created from the precursor peak. The exposure time is 1.5 sec (MET Time: 125875682.25 up to 125875683.75). There is total 50815 events (the output of "batbinevent") in the exposure. And a background file is created from the region which shows in Fig.1. The BGD exposure time is 19 sec (MET Time: 125875721 up to 125875740). The total counts of BGD file are 187121 counts.
Due to outside the BAT FOV, we add an option, "weighted=no", which don't use the Mask Weighting, when we make the event file. Then we fit the spectrum on Xspec using the response file which is simulated by SwiMM.
Here is the preliminary fitting result.
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I re-fit the spectrum, because there ware no error values in the parameters. (ver1.2)This spectrum is well modeled by bremsstrahlung. The temperature obtaines kT = 26.5 keV.
The temperatures of bursts from SGRs so obtained fall within the narrow range kT = 20-40 keV (astro-ph/0406133). I think the obtained temperature is likely to consistent.
The fitting parameters show as follow.
Model: bremss<1>
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Model: bremss<1>
Model Fit Model Component Parameter Unit Value
par par comp
1 1 1 bremss kT keV 26.5043 +/- 0.116759
2 2 1 bremss norm 89365.8 +/- 1665.03
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Chi-Squared = 3107.087 using 73 PHA bins.
Reduced chi-squared = 43.76178 for 71 degrees of freedom
Null hypothesis probability = 0.00
XSPEC>flux 20 194.9
Model flux 6205. photons ( 3.4131E-04 ergs)cm**-2 s**-1 ( 20.000-194.900)
Assuming a distance of ~15 kpc for SGR 1806-20 (Corbel & Eikenberry, A&A 419, 191,2004), the isotropic emission is ~1.4x10^43 erg. The isotropic energy in the intermediate bursts which are intermediate in duration, peak luminosity and energy between the common recurrent SGR bursts and the giant flares, range from 10^41 - 10^43 erg. the value of isotropic emission is reasonable.
Here is ver 1.1 description.