Last modified: December 2023

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/xswdem.html
AHELP for CIAO 4.16 Sherpa

xswdem

Context: models

Synopsis

The XSPEC wdem model: plasma emission, multi-temperature with power-law distribution of emission measure.

Syntax

xswdem

The xswdem model is an additive model component.

Description

The model is described at [1] .


Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.Tmax     thawed            1         0.01           20        keV
   mdl.beta     thawed          0.1         0.01            1           
   mdl.inv_slope thawed         0.25           -1           10           
   mdl.nH       frozen            1        1e-06        1e+20      cm^-3
   mdl.abundanc frozen            1            0           10           
   mdl.Redshift frozen            0       -0.999           10           
   mdl.switch   frozen            2 -3.40282e+38  3.40282e+38           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

Attribute Definition
Tmax The maximum temperature for power-law emission measure distribution.
beta The ratio of minimum to maxmum temperature.
inv_slope The inverse of the slope (labelled p in the XSPEC documentation).
nH Fixed at 1 for most applications.
abundanc The abundance relative to solar.
Redshift The redshift of the plasma.
switch What model to use: 0 calculates with MEKAL, 1 interpolates with MEKAL, and 2 interpoates with APEC.
norm The normalization of the model: see [1] for an explanation of the units.

References

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.

See Also

models
xsapec, xsvwdem