LogAbsorption

class sherpa.astro.optical.LogAbsorption(name='logabsorption')

Bases: sherpa.models.model.ArithmeticModel

Gaussian function for modeling absorption (log of fwhm).

This model is intended to be used to modify another model (e.g. by multiplying the two together). It is for use when the independent axis is in Angstroms.

fwhm

The full-width half-maximum of the feature in km/s.

pos

The center of the feature, in Angstroms.

tau

The optical depth of the feature.

See also

AbsorptionEdge, AbsorptionGaussian, AbsorptionLorentz, AbsorptionVoigt, EmissionGaussian, LogEmission, OpticalGaussian

Notes

The functional form of the model for points is:

f(x) = exp(-tau * (x / pos)^(term * alpha))

term = -1     if x >= pos

     = 1      otherwise

alpha = log(2) / log(1 + 0.5 * fwhm / c)

and for integrated data sets the low-edge of the grid is used.

Attributes Summary

thawedparhardmaxes
thawedparhardmins
thawedparmaxes
thawedparmins
thawedpars

Methods Summary

apply(outer, \*otherargs, \*\*otherkwargs)
calc(p, x[, xhi])
get_center()
guess(dep, \*args, \*\*kwargs)	Set an initial guess for the parameter values.
reset()
set_center(\*args, \*\*kwargs)
startup()
teardown()

Attributes Documentation

thawedparhardmaxes

thawedparhardmins

thawedparmaxes

thawedparmins

thawedpars

Methods Documentation

apply(outer, *otherargs, **otherkwargs)

calc(p, x, xhi=None, **kwargs)

get_center()

guess(dep, *args, **kwargs)

Set an initial guess for the parameter values.

Attempt to set the parameter values, and ranges, for the model to match the data values. This is intended as a rough guess, so it is expected that the model is only evaluated a small number of times, if at all.

reset()

set_center(*args, **kwargs)

startup()

teardown()