Last modified: December 2021

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/xsismabs.html
AHELP for CIAO 4.14 Sherpa

xsismabs

Context: models

Synopsis

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

Syntax

xsismabs

The xsismabs model is a multiplicative model component.

Description

The model is described at [1] .


Example

>>> 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.HeII     frozen            0            0        1e+06      10^16
   mdl.CI       thawed         33.1            0        1e+06      10^16
   mdl.CII      frozen            0            0        1e+06      10^16
   mdl.CIII     frozen            0            0        1e+06      10^16
   mdl.NI       thawed         8.32            0        1e+06      10^16
   mdl.NII      frozen            0            0        1e+06      10^16
   mdl.NIII     frozen            0            0        1e+06      10^16
   mdl.OI       thawed         67.6            0        1e+06      10^16
   mdl.OII      frozen            0            0        1e+06      10^16
   mdl.OIII     frozen            0            0        1e+06      10^16
   mdl.NeI      thawed           12            0        1e+06      10^16
   mdl.NeII     frozen            0            0        1e+06      10^16
   mdl.NeIII    frozen            0            0        1e+06      10^16
   mdl.MgI      thawed          3.8            0        1e+06      10^16
   mdl.MgII     frozen            0            0        1e+06      10^16
   mdl.MgIII    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.ArI      thawed         0.25            0        1e+06      10^16
   mdl.ArII     frozen            0            0        1e+06      10^16
   mdl.ArIII    frozen            0            0        1e+06      10^16
   mdl.CaI      thawed         0.22            0        1e+06      10^16
   mdl.CaII     frozen            0            0        1e+06      10^16
   mdl.CaIII    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).
HeII, CI, CII, CIII, NI, NII, NIII, OI, OII, OIII, NeI, NeII, NeIII, MgI, MgII, MgIII, Si_I, Si_II, Si_III, S_I, S_II, S_III, ArI, ArII, ArIII, CaI, CaII, CaIII, Fe The column for the species (in units of 10^16 atoms/cm^2).
redshift The redshift of the absorber.

Notes

As Sherpa parameter names are case insensitive the parameters for Silicon and Sulfur include an underscore character after the element name to avoid conflict: that is Si_I and S_I refer to the XSPEC SiI and SI parameters respectively.

References

XSPEC version

CIAO 4.14 comes with support for version 12.12.0 of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;
print(xspec.get_xsversion())'
12.12.0

Bugs

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