Last modified: December 2018

URL: http://cxc.harvard.edu/sherpa/ahelp/xstbrel.html
AHELP for CIAO 4.11 Sherpa v1

xstbrel

Context: models

Synopsis

The XSPEC TBrel model: ISM grain absorption.

Syntax

xstbrel

The xstbrel model is a multiplivative model component.

Description

The model is described at [1] .


Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.nH       thawed            1      -100000       100000      10^22
   mdl.He       frozen            1            0            5           
   mdl.C        frozen            1            0            5           
   mdl.N        frozen            1            0            5           
   mdl.O        frozen            1            0            5           
   mdl.Ne       frozen            1            0            5           
   mdl.Na       frozen            1            0            5           
   mdl.Mg       frozen            1            0            5           
   mdl.Al       frozen            1            0            5           
   mdl.Si       frozen            1            0            5           
   mdl.S        frozen            1            0            5           
   mdl.Cl       frozen            1            0            5           
   mdl.Ar       frozen            1            0            5           
   mdl.Ca       frozen            1            0            5           
   mdl.Cr       frozen            1            0            5           
   mdl.Fe       frozen            1            0            5           
   mdl.Co       frozen            1            0            5           
   mdl.Ni       frozen            1            0            5           
   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          0.5            0            1           
   mdl.N_dep    frozen            1            0            1           
   mdl.O_dep    frozen          0.6            0            1           
   mdl.Ne_dep   frozen            1            0            1           
   mdl.Na_dep   frozen         0.25            0            1           
   mdl.Mg_dep   frozen          0.2            0            1           
   mdl.Al_dep   frozen         0.02            0            1           
   mdl.Si_dep   frozen          0.1            0            1           
   mdl.S_dep    frozen          0.6            0            1           
   mdl.Cl_dep   frozen          0.5            0            1           
   mdl.Ar_dep   frozen            1            0            1           
   mdl.Ca_dep   frozen        0.003            0            1           
   mdl.Cr_dep   frozen         0.03            0            1           
   mdl.Fe_dep   frozen          0.3            0            1           
   mdl.Co_dep   frozen         0.05            0            1           
   mdl.Ni_dep   frozen         0.04            0            1           
   mdl.redshift frozen            0            0           10           

ATTRIBUTES

The attributes for this object are:

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 4.11 comes with support for version 12.10.0e of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;
print(xspec.get_xsversion())'
12.10.0e

Bugs

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

See Also

models
xstbabs, xstbfeo, xstbgas, xstbgrain, xstbpcf, xstbvarabs, xsztbabs