Synopsis
The XSPEC vwdem model: plasma emission, multi-temperature with power-law distribution of emission measure.
Syntax
xsvwdem The xsvwdem model is an additive model component.
Description
The model is described at [1] .
Example
>>> create_model_component("xsvwdem", "mdl")
>>> print(mdl)Create a component of the xsvwdem 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.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 -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. |
| He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni | The abundance of the element in solar units. |
| 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
- [1] https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelWdem.html
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.