    The XSPEC TBvarabs model: ISM grain absorption.

xstbvarabs
The xstbvarabs model is a multiplicative model component.

The model is described at [1] .

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

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

mdl Param Type Value Min Max Units ----- ---- ----- --- --- ----- mdl.nH thawed 1 0 1e+06 10^22 atoms / cm^2 mdl.He frozen 1 0 1 mdl.C frozen 1 0 1 mdl.N frozen 1 0 1 mdl.O frozen 1 0 1 mdl.Ne frozen 1 0 1 mdl.Na frozen 1 0 1 mdl.Mg frozen 1 0 1 mdl.Al frozen 1 0 1 mdl.Si frozen 1 0 1 mdl.S frozen 1 0 1 mdl.Cl frozen 1 0 1 mdl.Ar frozen 1 0 1 mdl.Ca frozen 1 0 1 mdl.Cr frozen 1 0 1 mdl.Fe frozen 1 0 1 mdl.Co frozen 1 0 1 mdl.Ni frozen 1 0 1 mdl.H2 frozen 0.2 0 1 mdl.rho frozen 1 0 5 g/cm^3 mdl.amin frozen 0.025 0 0.25 mum mdl.amax frozen 0.25 0 1 mum mdl.PL frozen 3.5 0 5 mdl.H_dep frozen 1 0 1 mdl.He_dep frozen 1 0 1 mdl.C_dep frozen 1 0 1 mdl.N_dep frozen 1 0 1 mdl.O_dep frozen 1 0 1 mdl.Ne_dep frozen 1 0 1 mdl.Na_dep frozen 1 0 1 mdl.Mg_dep frozen 1 0 1 mdl.Al_dep frozen 1 0 1 mdl.Si_dep frozen 1 0 1 mdl.S_dep frozen 1 0 1 mdl.Cl_dep frozen 1 0 1 mdl.Ar_dep frozen 1 0 1 mdl.Ca_dep frozen 1 0 1 mdl.Cr_dep frozen 1 0 1 mdl.Fe_dep frozen 1 0 1 mdl.Co_dep frozen 1 0 1 mdl.Ni_dep frozen 1 0 1 mdl.redshift frozen 0 -0.999 10

ATTRIBUTES

The attributes for this object are:

Attribute
Definition
nH
The equivalent hydrogen column (in units of 10^22 atoms/cm^2).
He, C, N, O, Ne, Na, Mg, Al, Si, S, Cl, Ar, Ca, Cr, Fe, Co, Ni
The abundance of the element in solar units.
H2
The equivalent molecular hydrogen column (in units of 10^22 atoms/cm^2).
rho
The grain density, in g/cm^3.
amin
The minimum grain size, in micro-meters.
amax
The maximum grain size, in micro-meters.
PL
The power-law index of grain sizes.
H_dep, He_dep, C_dep, N_dep, O_dep, Ne_dep, Na_dep, Mg_dep, Al_dep, Si_dep, S_dep, Cl_dep, Ar_dep, Ca_dep, Cr_dep, Fe_dep, Co_dep, Ni_dep
The grain depletion fraction of the element.
redshift
The redshift of the absorber.

Notes

The `set_xsabund` function changes the relative abundances of the elements, in particular the "wilm" setting.

References

[1] https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelTbabs.html

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; print(xspec.get_xsversion())'12.13.1e

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

December 2023