Last modified: December 2020

AHELP for CIAO 4.13 Sherpa v1


Context: models


The XSPEC nteea model: non-thermal pair plasma.



The xsnteea model is an additive model component.


The model is described at [1] .


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

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

   Param        Type          Value          Min          Max      Units
   -----        ----          -----          ---          ---      -----
   mdl.l_nth    thawed          100            0        10000           
   mdl.l_bb     thawed          100            0        10000           
   mdl.f_refl   thawed            0            0            4           
   mdl.kT_bb    frozen           10            1          100           
   mdl.g_max    frozen         1000            5        10000           
   mdl.l_th     frozen            0            0        10000           
   mdl.tau_p    frozen            0            0           10           
   mdl.G_inj    frozen            0            0            5           
   mdl.g_min    frozen          1.3            1         1000           
   mdl.g_0      frozen          1.3            1            5           
   mdl.radius   frozen        1e+13       100000        1e+16           
   mdl.pair_esc frozen            0            0            1           
   mdl.cosIncl  thawed         0.45         0.05         0.95           
   mdl.Fe_abund frozen            1          0.1           10           
   mdl.redshift frozen            0       -0.999           10           
   mdl.norm     thawed            1            0        1e+24           


The attributes for this object are:

Attribute Definition
l_nth The nonthermal electron compactness.
l_bb The blackbody compactness.
f_refl The scaling factor for reflection. This is 1 for an isotropic source above the disk.
kT_bb The blackbody temperature in eV.
g_max The maximum Lorentz factor.
l_th The thermal compactness. Set to 0 for a pure nonthermal plasma.
tau_p The Thomson optical depth of ionization electrons.
G_inj The electron injection index (0 for monoenergetic injection).
g_min The minimum Lorentz factor of the power law injection (not used for monoenergetic injection).
g_0 The minimum Lorentz factor for nonthermal reprocessing, in the range (1, g_min].
radius The radius in cm (for Coulomb/bremsstrahlung only).
pair_esc The pair escape rate in c.
cosIncl The cosine of the inclination angle.
Fe_abund The iron abundance relative to that set by the set_xsabund function.
redshift The redshift of the source.
norm The normalization of the model: see [1] for more details.


The precision of the numerical integration can be changed by using the set_xsxset function to set the value of the NTEEA_PRECISION keyword, which defines the fractional precision. The default is 0.01 (1%).


XSPEC version

CIAO 4.13 comes with support for version 12.10.1s of the XSPEC models. This can be checked with the following:

% python -c 'from sherpa.astro import xspec;


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