Plummer1D

class astropy.modeling.physical_models.Plummer1D(mass=1.0, r_plum=1.0, **kwargs)

Bases: astropy.modeling.Fittable1DModel

One dimensional Plummer density profile model.

Parameters

massfloat

Total mass of cluster.

r_plumfloat

Scale parameter which sets the size of the cluster core.

Notes

Model formula:

\[\rho(r)=\frac{3M}{4\pi a^3}(1+\frac{r^2}{a^2})^{-5/2}\]

References

1

http://adsabs.harvard.edu/full/1911MNRAS..71..460P

Attributes Summary

input_units	This property is used to indicate what units or sets of units the evaluate method expects, and returns a dictionary mapping inputs to units (or None if any units are accepted).
mass
param_names
r_plum

Methods Summary

evaluate(x, mass, r_plum)	Evaluate plummer density profile model.
fit_deriv(x, mass, r_plum)	Plummer1D model derivatives.

Attributes Documentation

input_units

This property is used to indicate what units or sets of units the evaluate method expects, and returns a dictionary mapping inputs to units (or None if any units are accepted).

Model sub-classes can also use function annotations in evaluate to indicate valid input units, in which case this property should not be overridden since it will return the input units based on the annotations.

mass = Parameter('mass', value=1.0)

param_names = ('mass', 'r_plum')

r_plum = Parameter('r_plum', value=1.0)

Methods Documentation

static evaluate(x, mass, r_plum)

Evaluate plummer density profile model.

static fit_deriv(x, mass, r_plum)

Plummer1D model derivatives.