rfxconv: angledependent reflection from an ionized disk
This convolution model from Chris Done combines the ionized disk table
model from Ross and Fabian with the Magdziarz & Zdziarski Compton
reflection code. It is described in Kolehmainen, Done & Diaz Trigo
(2011)
and is a modification of the model first described in Done &
Gierlinski (2006).
The algorithm used is as follows.
 Determine the average powerlaw index of the input spectrum
between 2 and 10 keV. For this index and the other input parameters
interpolate on the table models to generate the reflected spectrum
from the ionized disk.
 Estimate the average powerlaw index of the reflected spectrum
over the range 12  14 keV.
 Iterate over the Compton reflection models changing the
crosssection at 10 keV until a match is found with the index
calculated in the previous step.
 Renormalize the reflection spectrum calculated in step 1 to
match the Compton reflection calculated in step 3 at 14 keV.
 Calculate the final reflection spectrum by using the
renormalized ionized disk spectrum below 14 keV and the Compton
reflection spectrum above 14 keV.
When using this model it is essential to extend the energy range over
which the model is calculated because photons at higher energies are
Compton downscattered into the target energy range. The energy range
can be extended using the extend command. The upper limit on the
energies should be set above that for which the input spectrum has
significant flux. To speed up the model, calculation of the output
spectrum can be limited to energies below a given value by using xset
to define RFXCONV_MAX_E (in units of keV). For instance, suppose that
the original data extends up to 100 keV. To accurately determine the
reflection it may be necessary to extend the energy range up to 500
keV. Now to avoid calculating the output spectrum between 100 and 500
keV use the command xset RFXCONV_MAX_E 100.0.
The core of this model is a Greens' function integration with one
numerical integral performed for each model energy. The numerical
integration is done using an adaptive method which continues until
a given estimated fractional precision is reached. The precision can
be changed by setting RFXCONV_PRECISION eg xset RFXCONV_PRECISION 0.05.
The default precision is 0.01 (ie 1%).
To use different ionized disk table model files than those installed
change the directory searched for these files using xset RFXCONV_DIR.
The model parameters are as follows.
par1 = 
the relative reflection normalization. If
is negative then only the reflected component is
returned. 
par2 = 

par3 = 
the iron abundance relative to Solar. All other
elements are assumed to have Solar abundance. 
par4 = 
cosine of the inclination angle (degrees). 
par5 = 
the ionization parameter used by the table models. 
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Last modified: Friday, 23Aug2024 13:20:40 EDT
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