Last modified: December 2018

URL: http://cxc.harvard.edu/sherpa/ahelp/xsvvgnei.html
AHELP for CIAO 4.11 Sherpa v1

xsvvgnei

Context: models

Synopsis

The XSPEC vvgnei model: collisional plasma, non-equilibrium, temperature evolution.

Syntax

xsvvgnei

The xsvvgnei model is an additive model component.

Description

The model is described at [1] . The set_xsxset and get_xsxset functions are used to set and query the XSPEC XSET parameters, in particular the keyword "NEIVERS".

Deprecated in Sherpa 4.10.0

The kT_ave parameter has been renamed meanKT to match the XSPEC definition. The name kT_ave can still be used to access the parameter, but this name will be removed in a future release.


Example

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

Create a component of the xsvvgnei 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.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.Tau      thawed        1e+11        1e+08        5e+13     s/cm^3
   mdl.meankT   thawed            1       0.0808         79.9        keV
   mdl.redshift frozen            0       -0.999           10           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

kT

The temperature of the plasma, in keV.

H

The H abundance: it should be set to 0 to switch on and 1 to switch off the free-free continuum.

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, with respect to Solar.

Tau

The ionization timescale in units of s/cm^3.

meankT

The ionization timescale averaged plasma temperature in keV.

redshift

The redshift of the plasma.

norm

The normalization of the model: see [1] for an explanation of the units.

References

XSPEC version

CIAO 4.11 comes with support for version 12.10.0e of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;
print(xspec.get_xsversion())'
12.10.0e

Bugs

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

See Also

models
xsgnei, xsvgnei