xsvcempow

Context: models

Synopsis

The XSPEC vcempow model: plasma emission, multi-temperature using a power-law emission measure.

Syntax

xsvcempow

The xsvcempow model is an additive model component.

Description

The model is described at [1] .

Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.alpha    frozen            1         0.01           20           
   mdl.Tmax     thawed            1      0.02725          100        keV
   mdl.nH       frozen            1        1e-06        1e+20      cm^-3
   mdl.He       frozen            1            0           10           
   mdl.C        frozen            1            0           10           
   mdl.N        frozen            1            0           10           
   mdl.O        frozen            1            0           10           
   mdl.Ne       frozen            1            0           10           
   mdl.Na       frozen            1            0           10           
   mdl.Mg       frozen            1            0           10           
   mdl.Al       frozen            1            0           10           
   mdl.Si       frozen            1            0           10           
   mdl.S        frozen            1            0           10           
   mdl.Ar       frozen            1            0           10           
   mdl.Ca       frozen            1            0           10           
   mdl.Fe       frozen            1            0           10           
   mdl.Ni       frozen            1            0           10           
   mdl.Redshift frozen            0       -0.999           10           
   mdl.switch   frozen            2            0            3           
   mdl.norm     thawed            1            0        1e+24

ATTRIBUTES

The attributes for this object are:

Attribute	Definition
alpha	The power-law index of the emissivity function.
Tmax	The maximum temperature, 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; if 3 then SPEX data. See [1] for more details. This parameter can not be thawed.
norm	The normalization of the model.

References

[1]

Changes in CIAO

Added in CIAO 4.17

XSPEC version

CIAO 4.18 comes with support for version 12.14.0k of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;
print(xspec.get_xsversion())'
12.14.0k

Bugs

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