    The XSPEC ismabs model: A high resolution ISM absorption model with variable columns for individual ions.

xsismabs
The xsismabs model is a multiplicative model component.

The model is described at [1] .

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

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

mdl Param Type Value Min Max Units ----- ---- ----- --- --- ----- mdl.H thawed 0.1 0 1e+06 10^22 mdl.He_II frozen 0 0 1e+06 10^16 mdl.C_I thawed 33.1 0 1e+06 10^16 mdl.C_II frozen 0 0 1e+06 10^16 mdl.C_III frozen 0 0 1e+06 10^16 mdl.N_I thawed 8.32 0 1e+06 10^16 mdl.N_II frozen 0 0 1e+06 10^16 mdl.N_III frozen 0 0 1e+06 10^16 mdl.O_I thawed 67.6 0 1e+06 10^16 mdl.O_II frozen 0 0 1e+06 10^16 mdl.O_III frozen 0 0 1e+06 10^16 mdl.Ne_I thawed 12 0 1e+06 10^16 mdl.Ne_II frozen 0 0 1e+06 10^16 mdl.Ne_III frozen 0 0 1e+06 10^16 mdl.Mg_I thawed 3.8 0 1e+06 10^16 mdl.Mg_II frozen 0 0 1e+06 10^16 mdl.Mg_III frozen 0 0 1e+06 10^16 mdl.Si_I thawed 3.35 0 1e+06 10^16 mdl.Si_II frozen 0 0 1e+06 10^16 mdl.Si_III frozen 0 0 1e+06 10^16 mdl.S_I thawed 2.14 0 1e+06 10^16 mdl.S_II frozen 0 0 1e+06 10^16 mdl.S_III frozen 0 0 1e+06 10^16 mdl.Ar_I thawed 0.25 0 1e+06 10^16 mdl.Ar_II frozen 0 0 1e+06 10^16 mdl.Ar_III frozen 0 0 1e+06 10^16 mdl.Ca_I thawed 0.22 0 1e+06 10^16 mdl.Ca_II frozen 0 0 1e+06 10^16 mdl.Ca_III frozen 0 0 1e+06 10^16 mdl.Fe thawed 3.16 0 1e+06 10^16 mdl.redshift frozen 0 -1 10

ATTRIBUTES

The attributes for this object are:

Attribute
Definition
H
The equivalent hydrogen column (in units of 10^22 atoms/cm^2).
He_II, C_I, C_II, C_III, N_I, N_II, N_III, O_I, O_II, O_III, Ne_I, Ne_II, Ne_III, Mg_I, Mg_II, Mg_III, Si_I, Si_II, Si_III, S_I, S_II, S_III, Ar_I, Ar_II, Ar_III, Ca_I, Ca_II, Ca_III, Fe
The column for the species (in units of 10^16 atoms/cm^2).
redshift
The redshift of the absorber.

References

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

Changes in CIAO

All species names now have the form <element>_<state>, such as He_II and Ca_III. The old versions (HeII and CaIII) can still be used but a deprecation warning may be displayed.

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