Last modified: December 2023

AHELP for CIAO 4.16 Sherpa


Context: models


The XSPEC bexriv model: reflected e-folded broken power law, ionized medium.



The xsbexriv model is an additive model component.


The model is described at [1] .


>>> create_model_component("xsbexriv", "mdl")
>>> print(mdl)

Create a component of the xsbexriv model and display its default parameters. The output is:

   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.Gamma1   thawed            2          -10           10           
   mdl.breakE   thawed           10          0.1         1000        keV
   mdl.Gamma2   thawed            2          -10           10           
   mdl.foldE    thawed          100            1        1e+06        keV
   mdl.rel_refl thawed            0            0        1e+06           
   mdl.redshift frozen            0       -0.999           10           
   mdl.abund    frozen            1            0        1e+06           
   mdl.Fe_abund frozen            1            0        1e+06           
   mdl.cosIncl  frozen         0.45         0.05         0.95           
   mdl.T_disk   frozen        30000        10000        1e+06          K
   mdl.xi       thawed            1            0         5000   erg cm/s
   mdl.norm     thawed            1            0        1e+24           


The attributes for this object are:

Attribute Definition
Gamma1 The power-law index of the first power-law component.
breakE The break energy, in keV.
Gamma2 The power-law index of the second power-law component.
foldE The e-folding energy (Ec) in keV. If zero there is no cut off.
rel_refl The reflection scaling parameter (a value of 1 for an isotropic source above the disk).
redshift The redshift of the source.
abund The abundance of the elements heavier than He relative to their solar abundance, as set by the set_xsabund function.
Fe_abund The iron abundance relative to the solar abundance, as set by the set_xsabund function.
cosIncl The cosine of the inclination angle.
T_disk The disk temperature in K.
xi The disk ionization parameter: see [1] for an explanation.
norm The normalization of the model: see [1] for an explanation of the units.


The precision of the numerical integration can be changed by using the set_xsxset function to set the value of the BEXRIV_PRECISION keyword, which defines the fractional precision. The default is 0.01 (1%).


XSPEC version

CIAO 4.16 comes with support for version 12.13.1e of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;


See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

See Also

xsbexrav, xsireflect