Synopsis
The XSPEC tapec model: APEC emission spectrum with separate continuum and line temperatures.
Syntax
xstapec The xstapec model is an additive model component.
Description
The model is described at [1] . The set_xsabund and get_xsabund functions change and return the current settings for the relative abundances of the metals. 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("xstapec", "mdl")
>>> print(mdl)Create a component of the xstapec model and display its default parameters. The output is:
mdl Param Type Value Min Max Units ----- ---- ----- --- --- ----- mdl.kT thawed 1 0.008 64 keV mdl.kTi thawed 1 0.008 64 keV mdl.Abundanc frozen 1 0 5 mdl.Redshift frozen 0 -0.999 10 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. |
| Abundanc | The metal abundance of the plasma, as defined by the set_xsabund function and the "APEC_TRACE_ABUND" xset keyword (which defaults to 1.0). |
| Redshift | The redshift of the plasma. |
| norm | The normalization of the model: see [1] for an explanation of the units. |
References
- [1] https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelTapec.html
Changes in CIAO
Changed in CIAO 4.17
The Abundanc and Redshift parameters are now frozen by default to match XSPEC.
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.