Last modified: December 2018

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

xsvtapec

Context: models

Synopsis

The XSPEC vtapec model: APEC emission spectrum with separate continuum and line temperatures.

Syntax

xsvtapec

The xsvtapec 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 keywords "APECROOT", "APECTHERMAL", "APECVELOCITY", "APECNOLINES", and "APEC_TRACE_ABUND".


Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.kT       thawed          6.5       0.0808       68.447        keV
   mdl.kTi      thawed          6.5       0.0808       68.447        keV
   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.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 thawed            0       -0.999           10           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

kT

Continuum temperature, in keV.

kTi

Line temperature, in keV.

He, C, N, O, Ne, Mg, Al, Si, S, Ar, Ca, Fe, Ni

The abundance of the element in solar units. The trace element abundances are determined by the APEC_TRACE_ABUND xset keyword (the default is 1.0).

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
xstapec, xsvvtapec