LightGaussianRingAzimuthal

class dysmalpy.models.LightGaussianRingAzimuthal(tracer=None, **kwargs)

Bases: LightModel, _DysmalFittable3DModel

Light distribution following a Gaussian ring profile, with azimuthal brightness variation. (Reflection symmetric about one axis)

Parameters:

• R_peak (float) – Peak of gaussian (radius) in kpc

• FWHM (float) – FWHM of gaussian, in kpc

• L_tot (float) – Total luminsoity of component. Arbitrary units

• phi (float) – Azimuthal angle of bright side, counter-clockwise from blue major axis. In degrees.

• contrast (float) – Brightness contrast between dim and bright sides, dim/bright. Default: 1.

• gamma (float) – Scaling factor for how quickly the brightness changes occur from [0., abs(180.)].

• tracer (string) – (Attribute): Name of the dynamical tracer

Notes

Model formula, for the radial part:

\[I(r)=I_0\exp\left[-\frac{(r-r_{peak})^2}{2\sigma_R^2}\right]\]

Attributes Summary

FWHM
L_tot
R_peak
contrast
gamma
param_names	Names of the parameters that describe models of this type.
phi

Methods Summary

evaluate(x, y, z, R_peak, FWHM, L_tot, phi, ...)	Azimuthally varying Gaussian ring light surface density.
light_profile(x, y, z)	Azimuthally varying Gaussian ring light surface density.
sigma_R()

Attributes Documentation

FWHM = DysmalParameter('FWHM', value=1.0, bounds=(0, 50), prior=<dysmalpy.parameters.UniformPrior object>)

L_tot = DysmalParameter('L_tot', value=1.0, bounds=(0, 50), prior=<dysmalpy.parameters.UniformPrior object>)

R_peak = DysmalParameter('R_peak', value=1.0, bounds=(0, 50), prior=<dysmalpy.parameters.UniformPrior object>)

contrast = DysmalParameter('contrast', value=1.0, bounds=(0.0, 1.0), prior=<dysmalpy.parameters.UniformPrior object>)

gamma = DysmalParameter('gamma', value=1.0, bounds=(0, 100.0), prior=<dysmalpy.parameters.UniformPrior object>)

param_names = ('R_peak', 'FWHM', 'L_tot', 'phi', 'contrast', 'gamma')

Names of the parameters that describe models of this type.

The parameters in this tuple are in the same order they should be passed in when initializing a model of a specific type. Some types of models, such as polynomial models, have a different number of parameters depending on some other property of the model, such as the degree.

When defining a custom model class the value of this attribute is automatically set by the Parameter attributes defined in the class body.

phi = DysmalParameter('phi', value=0.0, bounds=(0, 360), prior=<dysmalpy.parameters.UniformPrior object>)

Methods Documentation

static evaluate(x, y, z, R_peak, FWHM, L_tot, phi, contrast, gamma)

Azimuthally varying Gaussian ring light surface density. Positions x,y,z in kpc

light_profile(x, y, z)

Azimuthally varying Gaussian ring light surface density.

Parameters:

• x (float or array) – Position at which to calculate the light profile, in kpc. In the galaxy frame.

• y (float or array) – Position at which to calculate the light profile, in kpc. In the galaxy frame.

• z (float or array) – Position at which to calculate the light profile, in kpc. In the galaxy frame.

Returns:

light – Relative line flux as a function of radius

Return type:

float or array

sigma_R()