Last modified: December 2018

URL: http://cxc.harvard.edu/sherpa/ahelp/xsbkn2pow.html
AHELP for CIAO 4.11 Sherpa v1

xsbkn2pow

Context: models

Synopsis

The XSPEC bkn2pow model: broken power law with two breaks.

Syntax

xsbkn2pow

The xsbkn2pow model is an additive model component.

Description

The model is described at [1] .


Example

>>> create_model_component("xsbkn2pow", "mdl")
>>> print(mdl)

Create a component of the xsbkn2pow model and display its default parameters. The output is:

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.PhoIndx1 thawed            1           -2            9           
   mdl.BreakE1  thawed            5         0.01        1e+06        keV
   mdl.PhoIndx2 thawed            2           -2            9           
   mdl.BreakE2  thawed           10         0.01        1e+06        keV
   mdl.PhoIndx3 thawed            3           -2            9           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

PhoIndx1

The power law photon index for energies less than BreakE1.

BreakE1

The first break energy, in keV.

PhoIndx2

The power law photon index for energies greater than BreakE1 but less than BreakE2.

BreakE2

The second break energy, in keV.

PhoIndx3

The power law photon index for energies greater than BreakE2.

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
xsbknpower, xscutoffpl, xspowerlaw, xszcutoffpl, xszpowerlw