Synopsis
The XSPEC bvvwdem model: plasma emission, multi-temperature with power-law distribution of emission measure.
Syntax
xsbvvwdem The xsbvvwdem model is an additive model component.
Description
The model is described at [1] .
Example
>>> create_model_component("xsbvvwdem", "mdl")
>>> print(mdl)Create a component of the xsbvvwdem 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.H frozen 1 0 1000 mdl.He frozen 1 0 1000 mdl.Li frozen 1 0 1000 mdl.Be frozen 1 0 1000 mdl.B frozen 1 0 1000 mdl.C frozen 1 0 1000 mdl.N frozen 1 0 1000 mdl.O frozen 1 0 1000 mdl.F 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.P frozen 1 0 1000 mdl.S frozen 1 0 1000 mdl.Cl frozen 1 0 1000 mdl.Ar frozen 1 0 1000 mdl.K frozen 1 0 1000 mdl.Ca frozen 1 0 1000 mdl.Sc frozen 1 0 1000 mdl.Ti frozen 1 0 1000 mdl.V frozen 1 0 1000 mdl.Cr frozen 1 0 1000 mdl.Mn frozen 1 0 1000 mdl.Fe frozen 1 0 1000 mdl.Co frozen 1 0 1000 mdl.Ni frozen 1 0 1000 mdl.Cu frozen 1 0 1000 mdl.Zn frozen 1 0 1000 mdl.Redshift frozen 0 -0.999 10 mdl.Velocity frozen 0 0 10000 km/s mdl.switch frozen 2 0 3 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. |
| H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn | The abundance of the element in solar units. |
| Redshift | The redshift of the plasma. |
| Velocity | The gaussian sigma for the velocity broadening (in km/s) which is only used when switch > 1. |
| 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: see [1] for an explanation of the units. |
References
- [1] https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelWdem.html
Changes in CIAO
Added in CIAO 4.17
XSPEC version
CIAO 4.17 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.