Edge¶

class sherpa.astro.models.Edge(name='edge')[source]¶

Bases: sherpa.models.model.ArithmeticModel

Photoabsorption edge model.

This model can be used when the independent axis is in energy or wavelength space.

space¶: This parameter is not fit (alwaysfrozen is set), and should be set to either 0, when the independent axis is energy with units of keV, or 1 when the axis is wavelength with units of Angstrom.

thresh¶: The edge position (in energy or wavelength units matching the data grid).

abs¶: The absorption coefficient.

Notes

A phenomenological photoabsorption edge model as a function of energy:

f(x) = exp(-abs * (x / thresh)^-3)   if x >= thresh

     = 1.0                           otherwise

or, as a function of wavelength:

f(x) = exp(-abs * (x / thresh)^3)    if x <= thresh

     = 1.0                           otherwise

Attributes Summary

`thawedparhardmaxes`
`thawedparhardmins`
`thawedparmaxes`
`thawedparmins`
`thawedpars`

Methods Summary

`apply`(outer, \otherargs, \\*otherkwargs)
`calc`(pars, xlo, \args, \\*kwargs)
`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(pars, xlo, *args, **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()¶