models

Context: models

Synopsis

Summary of Sherpa models (excluding XSPEC).

Description

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absorptionvoigt	This model has been replaced by Voigt1D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emissionvoigt	This model has been replaced by Voigt1D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 homogeneous 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.

Bugs

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