Synopsis
Load a XSPEC table model.
Syntax
load_xstable_model(modelname, filename, etable=False) modelname - str filename - str etable - bool, optional
Description
Create an additive ('atable', [1]), multiplicative ('mtable', [2]), or exponential ('etable', [3]) XSPEC table model component. These models may have multiple model parameters.
Examples
Example 1
Load in the XSPEC table model from the file 'bbrefl_1xsolar.fits' and create a model component labelled 'xtbl', which is then used in a source expression:
>>> load_xstable_model('xtbl', 'bbrefl_1xsolar.fits') >>> set_source(xsphabs.gal * xtbl) >>> print(xtbl)
Example 2
Load in an XSPEC etable model:
>>> load_xstable_model('etbl', 'etable.mod', etable=True)
PARAMETERS
The parameters for this function are:
Parameter | Definition |
---|---|
modelname | The identifier for this model component. |
filename | The name of the FITS file containing the data, which should match the XSPEC table model definition [4]. |
etable | Set if this is an etable (as there's no way to determine this from the file itself). Defaults to False. |
Notes
There is no support for table models that provide multiple spectra per parameter: that is, those with the NXFLTEXP keyword set.
NASA's HEASARC site contains a link to community-provided XSPEC table models.
References
- https://heasarc.gsfc.nasa.gov/docs/xanadu/xspec/manual/XSmodelAtable.html
- https://heasarc.gsfc.nasa.gov/docs/xanadu/xspec/manual/XSmodelMtable.html
- https://heasarc.gsfc.nasa.gov/docs/xanadu/xspec/manual/XSmodelEtable.html
- K. A. Arnaud, I. M. George & A. F. Tennant, "The OGIP Spectral File Format"
Changes in CIAO
Changed in CIAO 4.16
Parameters with negative DELTA values are now made frozen, to match XSPEC. Support for models which use the ESCALE keyword has been added.
Changed in CIAO 4.14
The etable argument has been added to allow exponential table models to be used.
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
Bugs
See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.
See Also
- modeling
- load_table_model