Last modified: December 2018

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

xspowerlaw

Context: models

Synopsis

The XSPEC powerlaw model: power law photon spectrum.

Syntax

xspowerlaw

The xspowerlaw model is an additive model component.

Description

The model is described at [1] .


Example

>>> 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           -2            9           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

PhoIndex

The power law photon index.

norm

The normalization of the model. See [1] for details, as its meaning depends on whether the "POW_EMIN" or "POW_EMAX" keywords have been set with set_xsxset .

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
xsbkn2pow, xsbknpower, xscutoffpl, xspegpwrlw, xszpowerlw