**absori**- Ionized absorber.
**acisabs**- Extra absorption due to contamination on the ACIS filters.
**ascac**- ASCA PSF mixing model.
**apec**- APEC thermal plasma model.
**atable**- Additive table model.
**bbody**- Blackbody spectrum.
**bbodyrad**- Blackbody spectrum with norm proportional to surface area.
**bexrav**- E-folded broken power-law reflected from neutral matter
**bexriv**- E-folded broken power-law reflected from ionized matter
**bknpower**- Broken powerlaw.
**bkn2pow**- Three-segment broken powerlaw.
**bmc**- Comptonization by relativistically moving matter.
**bremss**- Thermal bremsstrahlung.
**c6mekl**- 6th-order Chebyshev polynomial DEM using mekal.
**c6pmekl**- Exponential of 6th-order Chebyshev polyn. DEM using mekal.
**c6pvmkl**- Variable abundance version of c6pmekl
**c6vmekl**- Variable abundance version of c6mekl
**cabs**- Compton scattering (non-relativistic)
**cemekl**- Multi-temperature mekal.
**cevmkl**- Multi-temperature vmeka.
**cflow**- Cooling flow model.
**compbb**- Comptonized blackbody spectrum after Nishimura et al. 1986.
**compls**- Comptonization spectrum after Lamb and Sanford 1979.
**compst**- Comptonization spectrum after Sunyaev and Titarchuk 1980.
**comptt**- Comptonization spectrum after Titarchuk 1994.
**constant**- Energy-independent multiplicative factor.
**cutoffpl**- Powerlaw with high energy exponential rolloff.
**cyclabs**- Cyclotron absorption line.
**disk**- Disk model.
**diskbb**- Multiple blackbody disk model.
**diskline**- Line emission from relativistic accretion disk.
**diskm**- Disk model with gas pressure viscosity.
**disko**- Modified blackbody disk model.
**diskpn**- Accretion disk around a black hole.
**dust**- Dust scattering out of the beam.
**edge**- Absorption edge.
**equil**- Equilibrium ionization collisional plasma model from Borkowski.
**etable**- Table model for exponential of -1 times the input.
**expabs**- Low-energy exponential rolloff.
**expdec**- Exponential decay.
**expfac**- Exponential factor.
**gaussian**- Simple gaussian line profile.
**gnei**- Generalized single ionization NEI plasma model.
**grad**- GR accretion disk around a black hole.
**grbm**- Gamma-ray burst model.
**gsmooth**- Gaussian smoothing with an energy dependent sigma.
**highecut**- High energy cutoff.
**hrefl**- Simple reflection model good up to 15 keV.
**laor**- Line from accretion disk around a black hole.
**lorentz**- Lorentzian line profile.
**lsmooth**- Lorentzian smoothing with an energy dependent sigma.
**meka**- Mewe-Gronenschild-Kaastra thermal plasma (1992).
**mekal**- Mewe-Kaastra-Liedahl thermal plasma (1995).
**mkcflow**- Cooling flow model based on mekal.
**mtable**- Multiplicative table model.
**nei**- Simple nonequilibrium ionization plasma model.
**notch**- Notch line absorption.
**npshock**- Plane-parallel shock with ion and electron temperatures.
**nsa**- Neutron star with hydrogen atmosphere.
**pwab**- Power-law distribution of neutral absorbers.
**nteea**- Pair plasma model.
**pcfabs**- Partial covering fraction absorption.
**pegpwrlw**- Powerlaw with pegged normalization.
**pexrav**- Exponentially cut-off power-law reflected from neutral matter.
**pexriv**- Exponentially cut-off power-law reflected from ionized matter.
**phabs**- Photo-electric absorption
**pileup**- CCD pile-up model
**plabs**- Absorption model with power-law dependence on energy.
**plcabs**- Cut-off powerlaw observed through dense, cold matter.
**posm**- Positronium continuum.
**powerlaw**- Simple photon power law.
**projct**- 3-D to 2-D projection mixing model.
**pshock**- Constant temperature, plane-parallel shock plasma model.
**raymond**- Raymond-Smith thermal plasma.
**redden**- IR/optical/UV extinction from Cardelli et al. (1989)
**redge**- Recombination edge.
**reflect**- Convolution model for reflection from neutral matter
**refsch**- E-folded power-law reflected from an ionized relativistic disk.
**rgsxsrc**- Convolution model for extended sources with the XMM RGS.
**sedov**- Sedov model with electron and ion temperatures.
**smaug**- Model for an optically-thin, spherically-symmetric thermal plasma.
**smedge**- Smoothed absorption edge.
**spline**- Spline multiplicative factor.
**srcut**- Synchrotron radiation from cut-off electron distribution.
**sresc**- Synchrotron radiation from escape-limited electron distribution.
**SSS_ice**- Einstein Observatory SSS ice absorption.
**step**- Step function convolved with gaussian.
**tbabs**- Absorption due to the ISM including molecules and grains.
**tbgrain**- ISM absorption with variable molecule and grain fractions.
**tbvarabs**- ISM absorption with variable abundances and grain depletion.
**uvred**- UV reddening.
**vapec**- APEC thermal plasma model with variable abundances.
**varabs**- Photoelectric absorption with variable abundances.
**vbremss**- Thermal bremsstrahlung spectrum with variable H/He.
**vequil**- As equil but with variable abundances.
**vgnei**- As gnei but with variable abundances.
**vmcflow**- Cooling flow model based on vmekal.
**vmeka**- M-G-K thermal plasma with variable abundances.
**vmekal**- M-K-L thermal plasma with variable abundances.
**vnei**- As nei but with variable abundances.
**vnpshock**- As npshock but with variable abundances.
**vphabs**- Photoelectric absorption with variable abundances.
**vpshock**- As pshock but with variable abundances.
**vraymond**- Raymond-Smith thermal plasma with variable abundances.
**vsedov**- As sedov but with variable abundances.
**wabs**- Photoelectric absorption (Morrison & McCammon).
**wndabs**- Photoelectric absorption with low energy window.
**xion**- The reflected spectrum from a photo-ionized accretion disk.
**xmmpsf**- XMM PSF mixing model.
**zbbody**- Redshifted blackbody.
**zbremss**- Redshifted thermal bremsstrahlung.
**zedge**- Redshifted absorption edge.
**zgauss**- Redshifted gaussian.
**zhighect**- Redshifted high energy cut-off.
**zpcfabs**- Redshifted partial covering absorption.
**zphabs**- Redshifted photoelectric absorption
**zpowerlw**- Redshifted powerlaw.
**ztbabs**- Redshifted ISM absorption without grains.
**zvarabs**- Redshifted photoelectric absorption with variable abundances.
**zvfeabs**- Redshifted absorption with variable iron abundance.
**zvphabs**- Redshifted photoelectric absorption with variable abundances.
**zwabs**- Redshifted ``Wisconsin absorption.''
**zwndabs**- Redshifted photoelectric absorption with low energy window.