Shell2D

class sherpa.astro.models.Shell2D(name='shell2d')

Bases: sherpa.models.model.ArithmeticModel

A homogenous spherical 3D shell projected onto 2D.

xpos

The center of the shell on the x0 axis.

ypos

The center of the shell on the x1 axis.

ampl

The amplitude.

r0

The line-of-sight distance.

width

The width of the shell.

See also

Disk2D

Notes

The functional form of the model for points is:

f(x0,x1) = ampl * r(x0,x1)

         = 0     otherwise

r(x0,x1) = ?

For grids, the x0lo,x1lo values are used in the above equation.

It is not correct for very large shells on the sky.

This model was provided by Christoph Deil.

Attributes Summary

thawedparhardmaxes
thawedparhardmins
thawedparmaxes
thawedparmins
thawedpars

Methods Summary

apply(outer, \*otherargs, \*\*otherkwargs)
calc(p, x, y, \*args, \*\*kwargs)	Homogeneously emitting spherical shell, projected along the z-direction (this is not 100% correct for very large shells on the sky).
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, y, *args, **kwargs)

Homogeneously emitting spherical shell, projected along the z-direction (this is not 100% correct for very large shells on the sky).

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()