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
- [1] https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelTbabs.html
XSPEC version
CIAO 4.17 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.