    Summary of Sherpa models (excluding XSPEC).

The following table lists most of the models available within Sherpa. See "ahelp xs" for those models provided by XSPEC, "ahelp tablemodel" for table models, and "ahelp load_user_model" for user-supplied models, respectively.

One-dimensional Sherpa models
Model name
Description
absorptionedge
Optical model of an absorption edge.
absorptiongaussian
Gaussian function for modeling absorption (equivalent width).
absorptionlorentz
Lorentz function for modeling absorption (equivalent width).
absorptionvoigt
This model has been replaced by Voigt1D
accretiondisk
A model of emission due to an accretion disk.
atten
Model the attenuation by the Inter-Stellar Medium (ISM).
bbody
A one-dimensional Blackbody model.
bbodyfreq
A one-dimensional Blackbody model (frequency).
beta1d
One-dimensional beta model function.
blackbody
Emission from a black body as a function of wavelength.
box1d
One-dimensional box function.
bpl1d
One-dimensional broken power-law function.
bremsstrahlung
Bremsstrahlung emission.
brokenpowerlaw
Broken power-law model.
ccm
Galactic extinction: the Cardelli, Clayton, and Mathis model.
const1d
A constant model for one-dimensional data.
cos
One-dimensional cosine function.
delta1d
One-dimensional delta function.
dered
A de-reddening model.
edge
Photoabsorption edge model.
emissiongaussian
Gaussian function for modeling emission.
emissionlorentz
Lorentz function for modeling emission.
emissionvoigt
This model has been replaced by Voigt1D
erf
One-dimensional error function.
erfc
One-dimensional complementary error function.
exp
One-dimensional exponential function.
exp10
One-dimensional exponential function, base 10.
fm
UV extinction curve: Fitzpatrick and Massa 1988.
gauss1d
One-dimensional gaussian function.
jdpileup
A CCD pileup model for the ACIS detectors on Chandra.
linebroad
A one-dimensional line-broadening profile.
lmc
LMC extinction: the Howarth model.
log
One-dimensional natural logarithm function.
log10
One-dimensional logarithm function, base 10.
logabsorption
Gaussian function for modeling absorption (log of fwhm).
logemission
Gaussian function for modeling emission (log of fwhm).
logparabola
One-dimensional log-parabolic function.
lorentz1d
One-dimensional normalized Lorentz model function.
normbeta1d
One-dimensional normalized beta model function.
normgauss1d
One-dimensional normalised gaussian function.
opticalgaussian
Gaussian function for modeling absorption (optical depth).
poisson
One-dimensional Poisson function.
polynom1d
One-dimensional polynomial function of order 8.
polynomial
Polynomial model of order 5.
powerlaw
Power-law model.
powlaw1d
One-dimensional power-law function.
pseudovoigt1d
A weighted sum of a Gaussian and Lorentzian distribution.
recombination
Optically-thin recombination continuum model.
scale1d
A constant model for one-dimensional data.
schechter
One-dimensional Schechter model function.
seaton
Galactic extinction: the Seaton model from Synphot.
sin
One-dimensional sine function.
sm
Galactic extinction: the Savage & Mathis model.
smc
SMC extinction: the Prevot et al. 1984 model.
sqrt
One-dimensional square root function.
stephi1d
One-dimensional step function.
steplo1d
One-dimensional step function.
tan
One-dimensional tan function.
voigt1d
One dimensional Voigt profile.
xgal
Extragalactic extinction: Calzetti, Kinney and Storchi-Bergmann

Two-dimensional Sherpa models
Model name
Description
beta2d
Two-dimensional beta model function.
box2d
Two-dimensional box function.
const2d
A constant model for two-dimensional data.
delta2d
Two-dimensional delta function.
devaucouleurs2d
Two-dimensional de Vaucouleurs model.
disk2d
Two-dimensional uniform disk model.
gauss2d
Two-dimensional gaussian function.
hubblereynolds
Two-dimensional Hubble-Reynolds model.
lorentz2d
Two-dimensional un-normalised Lorentz function.
normgauss2d
Two-dimensional normalised gaussian function.
polynom2d
Two-dimensional polynomial function.
scale2d
A constant model for two-dimensional data.
sersic2d
Two-dimensional Sersic model.
shell2d
A homogenous spherical 3D shell projected onto 2D.
sigmagauss2d
Two-dimensional gaussian function (varying sigma).

Are models evaluated at a point or across a bin?

The integration of models in Sherpa is controlled by an integration flag in each model structure. Refer to"ahelp integrate" for information on integrating model components.

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

December 2023