Last modified: December 2022

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/xsvmekal.html
AHELP for CIAO 4.15 Sherpa

xsvmekal

Context: models

Synopsis

The XSPEC vmekal model: emission, hot diffuse gas (Mewe-Kaastra-Liedahl).

Syntax

xsvmekal

The xsvmekal model is an additive model component.

Description

The model is described at [1] .


Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.kT       thawed            1       0.0808         79.9        keV
   mdl.nH       frozen            1        1e-06        1e+20       cm-3
   mdl.He       frozen            1            0         1000           
   mdl.C        frozen            1            0         1000           
   mdl.N        frozen            1            0         1000           
   mdl.O        frozen            1            0         1000           
   mdl.Ne       frozen            1            0         1000           
   mdl.Na       frozen            1            0         1000           
   mdl.Mg       frozen            1            0         1000           
   mdl.Al       frozen            1            0         1000           
   mdl.Si       frozen            1            0         1000           
   mdl.S        frozen            1            0         1000           
   mdl.Ar       frozen            1            0         1000           
   mdl.Ca       frozen            1            0         1000           
   mdl.Fe       frozen            1            0         1000           
   mdl.Ni       frozen            1            0         1000           
   mdl.redshift frozen            0       -0.999           10           
   mdl.switch   frozen            1 -3.40282e+38  3.40282e+38           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

Attribute Definition
kT The temperature of the plasma, in keV.
nH H density, in cm^-3.
He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni The abundance relative to Solar.
redshift The redshift of the plasma.
switch If 0, the mekal code is run to evaluate the model; if 1 then interpolation of the mekal data is used; if 2 then interpolation of APEC data is used. See [1] for more details. This parameter can not be thawed.
norm The normalization of the model: see [1] for an explanation of the units.

References

XSPEC version

CIAO 4.15 comes with support for version 12.12.1c of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;
print(xspec.get_xsversion())'
12.12.1c

Bugs

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