AbsorptionGaussian¶

class sherpa.astro.optical.AbsorptionGaussian(name='absorptiongaussian')[source]¶

Bases: sherpa.models.model.ArithmeticModel

Gaussian function for modeling absorption (equivalent width).

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 model in km/s.

pos¶: The center of the gaussian, in Angstroms.

ewidth¶: The equivalent width of the model.

limit¶: The model is only evaluated for points that lie within limit sigma of pos. It is a hidden parameter, with a value fixed at 4.

Notes

The functional form of the model for points is:

f(x) = 1 - ampl * exp(-0.5 * ((x - pos)/sigma)^2)

ampl = ewidth / sigma / 2.50662828

sigma = pos * fwhm / (2.354820044 * c)

and for integrated data sets the low-edge of the grid is used. The calculation is only done for those points that are in the range:

|x - pos| < limit * sigma

Outside this range the model is set to 1.

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)[source]¶

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()¶