Last modified: December 2018

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

xsapec

Context: models

Synopsis

The XSPEC apec model: APEC emission spectrum.

Syntax

xsapec

The xsapec model is an additive model component.

Description

The model is described at [1] . The set_xsabund and get_xsabund functions change and return the current settings for the relative abundances of the metals. The set_xsxset and get_xsxset functions are used to set and query the XSPEC XSET parameters, in particular the keywords "APECROOT", "APECTHERMAL", "APECVELOCITY", and "APEC_TRACE_ABUND".


Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.kT       thawed            1        0.008           64        keV
   mdl.Abundanc frozen            1            0            5           
   mdl.redshift frozen            0       -0.999           10           
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

kT

The temperature of the plasma, in keV.

Abundanc

The metal abundance of the plasma, as defined by the set_xsabund function and the "APEC_TRACE_ABUND" xset keyword.

redshift

The redshift of the plasma.

norm

The normalization of the model: see [1] for an explanation of the units.

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
xsbapec, xsbvapec, xsbvvapec, xsnlapec, xssnapec, xsvapec, xsvvapec