    The XSPEC bvtapec model: velocity broadened APEC emission spectrum with separate continuum and line temperatures.

xsbvtapec
The xsbvtapec model is an additive model component.

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" and "APEC_TRACE_ABUND".

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

Create a component of the xsbvtapec 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 1000 mdl.C frozen 1 0 1000 mdl.N frozen 1 0 1000 mdl.O frozen 1 0 1000 mdl.Ne frozen 1 0 1000 mdl.Mg frozen 1 0 1000 mdl.Al frozen 1 0 1000 mdl.Si frozen 1 0 1000 mdl.S frozen 1 0 1000 mdl.Ar frozen 1 0 1000 mdl.Ca frozen 1 0 1000 mdl.Fe frozen 1 0 1000 mdl.Ni frozen 1 0 1000 mdl.Redshift thawed 0 -0.999 10 mdl.Velocity thawed 0 0 10000 km/s mdl.norm thawed 1 0 1e+24

ATTRIBUTES

The attributes for this object are:

Attribute
Definition
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.
Velocity
The gaussian sigma of the velocity broadening, in km/s.
norm
The normalization of the model: see [1] for an explanation of the units.

References

[1] https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelBtapec.html

Changes in CIAO

The maximum for the Velocity parameter has been changed from 10^6 to 10^4 km/s.

XSPEC version

CIAO 4.16 comes with support for version 12.13.1e of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec; print(xspec.get_xsversion())'12.13.1e

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

December 2023