xstbgrain

Context: models

Synopsis

The XSPEC TBgrain model: ISM grain absorption.

Syntax

xstbgrain

The xstbgrain model is a multiplicative model component.

Description

The model is described at [1] .

Example

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

Create a component of the xstbgrain 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.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

ATTRIBUTES

The attributes for this object are:

Attribute	Definition
nH	The equivalent hydrogen column (in units of 10^22 atoms/cm^2).
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.

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

Bugs

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