Synopsis
The XSPEC TBvarabs model: ISM grain absorption.
Syntax
xstbvarabs The xstbvarabs model is a multiplicative model component.
Description
The model is described at [1] .
Example
>>> 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
XSPEC version
CIAO 4.18 comes with support for version 12.14.0k of the XSPEC models. This can be checked with the following:
% python -c 'from sherpa.astro import xspec; print(xspec.get_xsversion())' 12.14.0k
Bugs
See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.