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, and "ahelp tablemodel" and "ahelp load_user_model" for information on table and user-supplied models, respectively.

Sherpa models (exclding those from XSPEC)

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	Voigt function for modeling absorption (equivalent width).
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.
beta2d	Two-dimensional beta model function.
blackbody	Emission from a black body.
box1d	One-dimensional box function.
box2d	Two-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.
const2d	A constant model for two-dimensional data.
cos	One-dimensional cosine function.
delta1d	One-dimensional delta function.
delta2d	Two-dimensional delta function.
dered	A de-reddening model.
devaucouleurs2d	Two-dimensional de Vaucouleurs model.
disk2d	Two-dimensional uniform disk model.
edge	Photoabsorption edge model.
emissiongaussian	Gaussian function for modeling emission.
emissionlorentz	Lorentz function for modeling emission.
emissionvoigt	Voigt function for modeling emission.
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.
gauss2d	Two-dimensional gaussian function.
hubblereynolds	Two-dimensional Hubble-Reynolds model.
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.
lorentz2d	Two-dimensional un-normalised Lorentz function.
normbeta1d	One-dimensional normalized beta model function.
normgauss1d	One-dimensional normalised gaussian function.
normgauss2d	Two-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.
polynom2d	Two-dimensional polynomial function.
polynomial	Polynomial model of order 5.
powerlaw	Power-law model.
powlaw1d	One-dimensional power-law function.
recombination	Optically-thin recombination continuum model.
scale1d	A constant model for one-dimensional data.
scale2d	A constant model for two-dimensional data.
schechter	One-dimensional Schecter model function.
seaton	Galactic extinction: the Seaton model from Synphot.
sersic2d	Two-dimensional Sersic model.
shell2d	A homogenous spherical 3D shell projected onto 2D.
sigmagauss2d	Two-dimensional gaussian function (varying sigma).
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.
xgal	Extragalactic extinction: Calzetti, Kinney and Storchi-Bergmann

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