Last modified: December 2019

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/xszbknpower.html
AHELP for CIAO 4.12 Sherpa v1

xszbknpower

Context: models

Synopsis

The XSPEC bknpower model: broken power law.

Syntax

xszbknpower

The xszbknpower model is an additive model component.

Description

The model is described at [1] .


Example

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

Create a component of the xszbknpower model and display its default parameters. The output is:

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.PhoIndx1 thawed            1           -2            9           
   mdl.BreakE   thawed            5         0.01        1e+06        keV
   mdl.PhoIndx2 thawed            2           -2            9           
   mdl.Redshift frozen            0       -0.999           10           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

PhoIndx1

The power law photon index for energies less than BreakE.

BreakE

The break energy, in keV.

PhoIndx2

The power law photon index for energies greater than BreakE.

Redshift

The redshift.

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 4.12 comes with support for version 12.10.1n of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;
print(xspec.get_xsversion())'
12.10.1n

Bugs

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