Last modified: December 2025

URL: https://cxc.cfa.harvard.edu/sherpa/ahelp/xsbcempow.html
AHELP for CIAO 4.18 Sherpa

xsbcempow

Context: models

Synopsis

The XSPEC bcempow model: plasma emission, multi-temperature using a power-law emission measure

Syntax

xsbcempow

The xsbcempow model is an additive model component.

Description

The model is described at [1] .


Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.alpha    frozen            1         0.01           20           
   mdl.Tmax     thawed            1      0.02725          100        keV
   mdl.nH       frozen            1        1e-06        1e+20      cm^-3
   mdl.abundanc frozen            1            0           10           
   mdl.Redshift frozen            0       -0.999           10           
   mdl.Velocity frozen            0            0        10000       km/s
   mdl.switch   frozen            2            0            3           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

Attribute Definition
alpha The power-law index of the emissivity function.
Tmax The maximum temperature, in keV.
nH H density, in cm^-3.
abundanc The abundance relative to Solar, as set by set_xsabund .
Redshift The redshift of the plasma.
Velocity The gaussian sigma of the velocity broadening, in km/s.
switch If 0, the mekal code is run to evaluate the model; if 1 then interpolation of the mekal data is used; if 2 then interpolation of APEC data is used; if 3 then SPEX data. See [1] for more details. This parameter can not be thawed.
norm The normalization of the model.

References

[1]

Changes in CIAO

Added in CIAO 4.17

XSPEC version

CIAO 4.18 comes with support for version 12.14.0k of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;
print(xspec.get_xsversion())'
12.14.0k

Bugs

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

See Also

models
xsbvcempow, xscempow