xsvgadem

Context: models

Synopsis

The XSPEC vgadem model: plasma emission, multi-temperature with gaussian distribution of emission measure.

Syntax

xsvgadem

The xsvgadem 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. See the xsapec documentation for settings relevant to the APEC model (i.e. when switch=2 ).

Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.Tmean    frozen            4         0.01           20        keV
   mdl.Tsigma   thawed          0.1         0.01          100        keV
   mdl.nH       frozen            1        1e-06        1e+20      cm^-3
   mdl.He       frozen            1            0           10           
   mdl.C        frozen            1            0           10           
   mdl.N        frozen            1            0           10           
   mdl.O        frozen            1            0           10           
   mdl.Ne       frozen            1            0           10           
   mdl.Na       frozen            1            0           10           
   mdl.Mg       frozen            1            0           10           
   mdl.Al       frozen            1            0           10           
   mdl.Si       frozen            1            0           10           
   mdl.S        frozen            1            0           10           
   mdl.Ar       frozen            1            0           10           
   mdl.Ca       frozen            1            0           10           
   mdl.Fe       frozen            1            0           10           
   mdl.Ni       frozen            1            0           10           
   mdl.Redshift frozen            0       -0.999           10           
   mdl.switch   frozen            2            0            3           
   mdl.norm     thawed            1            0        1e+24

ATTRIBUTES

The attributes for this object are:

Attribute	Definition
Tmean	The mean temperature for the gaussian emission measure distribution, in keV.
Tsigma	The sigma of the temperature distribution for the gaussian emission measure, in keV.
nH	H density, in cm^-3.
He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni	The abundance of the element in solar units.
Redshift	The redshift of the plasma.
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 (only usable with XSPEC 12.14.0 or later). See [1] for more details. This parameter can not be thawed.
norm	The normalization of the model.

References

[1] https://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/XSmodelGadem.html

Changes in CIAO

Changed in CIAO 4.17

The maximum value of the switch parameter is now 3.

XSPEC version

CIAO 4.17 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.