Last modified: December 2025

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

xsnsatmos

Context: models

Synopsis

The XSPEC nsatmos model: NS Hydrogen Atmosphere model with electron conduction and self-irradiation.

Syntax

xsnsatmos

The xsnsatmos model is an additive model component.

Description

The model is described at [1] .


Example

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

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

mdl
   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.LogT_eff thawed            6            5          6.5          K
   mdl.M_ns     thawed          1.4          0.5            3       Msun
   mdl.R_ns     thawed           10            5           30         km
   mdl.dist     thawed           10          0.1          100        kpc
   mdl.norm     thawed            1            0        1e+24           

ATTRIBUTES

The attributes for this object are:

Attribute Definition
LogT_eff The log of Teff, the unredshifted effective temperature.
M_ns The neutron star gravitational mass, in units of the solar mass.
R_ns The "true" neutron star radius, in km.
dist The distance to the neutron star, in kpc.
norm The fraction of the neutron star surface emitting.

References

[1]

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.