The XSPEC powerlaw model: power law photon spectrum.
xspowerlaw The xspowerlaw model is an additive model component.
The model is described at  .
>>> create_model_component("xspowerlaw", "mdl") >>> print(mdl)
Create a component of the xspowerlaw model and display its default parameters. The output is:
mdl Param Type Value Min Max Units ----- ---- ----- --- --- ----- mdl.PhoIndex thawed 1 -3 10 mdl.norm thawed 1 0 1e+24
The attributes for this object are:
|PhoIndex||The power law photon index.|
|norm||The normalization of the model. See  for details, as its meaning depends on whether the "POW_EMIN" or "POW_EMAX" keywords have been set with set_xsxset .|
-  https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelPowerlaw.html
CIAO 4.15 comes with support for version 12.12.1c of the XSPEC models. This can be checked with the following:
% python -c 'from sherpa.astro import xspec; print(xspec.get_xsversion())' 12.12.1c
See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.