DeVaucouleurs2D

class sherpa.astro.models.DeVaucouleurs2D(name='devaucouleurs2d')[source] [edit on github]

Bases: sherpa.models.model.RegriddableModel2D

Two-dimensional de Vaucouleurs model.

A spatial de Vaucouleurs profile which is a formulation of the R^(1/4) law introduced by [1]. It is a special case of the Sersic2D model with n=4, as described in [2], [3], and [4].

r0

The core radius.

xpos

The center of the model on the x0 axis.

ypos

The center of the model on the x1 axis.

ellip

The ellipticity of the model.

theta

The angle of the major axis. It is in radians, measured counter-clockwise from the X0 axis (i.e. the line X1=0).

ampl

The amplitude refers to the maximum peak of the model.

Notes

The model used is the same as the Sersic2D model with n=4.

References

[1]de Vaucouleurs G., 1948, Ann. d’Astroph. 11, 247 http://adsabs.harvard.edu/abs/1948AnAp…11..247D
[2]http://ned.ipac.caltech.edu/level5/March05/Graham/Graham2.html
[3]Graham, A. & Driver, S., 2005, PASA, 22, 118 http://adsabs.harvard.edu/abs/2005PASA…22..118G
[4]Ciotti, L. & Bertin, G., A&A, 1999, 352, 447-451 http://adsabs.harvard.edu/abs/1999A%26A…352..447C

Attributes Summary

thawedparhardmaxes
thawedparhardmins
thawedparmaxes
thawedparmins
thawedpars

Methods Summary

apply(outer, *otherargs, **otherkwargs)
calc(*args, **kwargs) Evaluate the model on a grid.
get_center()
guess(dep, *args, **kwargs) Set an initial guess for the parameter values.
regrid(*arrays)
reset()
set_center(xpos, ypos, *args, **kwargs)
startup(cache) Called before a model may be evaluated multiple times.
teardown() Called after a model may be evaluated multiple times.

Attributes Documentation

thawedparhardmaxes
thawedparhardmins
thawedparmaxes
thawedparmins
thawedpars

Methods Documentation

apply(outer, *otherargs, **otherkwargs) [edit on github]
calc(*args, **kwargs)[source] [edit on github]

Evaluate the model on a grid.

Parameters:
  • p (sequence of numbers) – The parameter values to use. The order matches the pars field.
  • *args – The model grid. The values can be scalar or arrays, and the number depends on the dimensionality of the model and whether it is being evaluated over an integrated grid or at a point (or points).
get_center()[source] [edit on github]
guess(dep, *args, **kwargs)[source] [edit on github]

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.

regrid(*arrays) [edit on github]
reset() [edit on github]
set_center(xpos, ypos, *args, **kwargs)[source] [edit on github]
startup(cache) [edit on github]

Called before a model may be evaluated multiple times.

See also

teardown()

teardown() [edit on github]

Called after a model may be evaluated multiple times.

See also

setup()