InfThinMassiveGaussianRing

class dysmalpy.models.InfThinMassiveGaussianRing(invh=None)

Bases: object

Class to handle circular velocities / enclosed mass profiles for an infinitely thin, massive Gaussian ring.

Lookup tables are numerically calculated, following B&T and Bovy online galaxies textbook.

The lookup table provides rotation curves for Gaussian rings with invh = 0.5 - 8 at steps of 0.1 and invq = [1, 2, 3, 4, 5, 6, 7, 8, 10, 20, 100], where \(\mathrm{invh} = R_{\mathrm{peak}} / \mathrm{FWHM}_{\mathrm{ring}}\) If the given n and/or invq are not one of these values then the nearest ones are used.

Parameters:

invh (float) – Ratio of R_peak / ring_FWHM

Attributes Summary

invh

Methods Summary

enclosed_mass(R, R_peak, total_mass)	Calculate enclosed mass for a inf thin massive gaussian Ring
potential_gradient(R, R_peak, total_mass)	Calculate potential gradient for a inf thin massive gaussian Ring
read_ring_table()

Attributes Documentation

invh

Methods Documentation

enclosed_mass(R, R_peak, total_mass)

Calculate enclosed mass for a inf thin massive gaussian Ring

Parameters:

• R (float or array) – Radius or radii at which to calculate the enclosed in kpc

• R_peak (float) – Peak of Gaussian ring in kpc

• total_mass (float) – Total mass of the Gaussian ring component

Returns:

vcirc – Circular velocity at each given R

Return type:

float or array

Notes

This function determines the enclosed as a function of radius for a massive Gaussian ring component with a total mass, total_mass, and a ring peak radius to ring FWHM ratio, invh. This uses numerically calculated lookup tables.

potential_gradient(R, R_peak, total_mass)

Calculate potential gradient for a inf thin massive gaussian Ring

Parameters:

• R (float or array) – Radius or radii at which to calculate the potential gradient in kpc

• R_peak (float) – Peak of Gaussian ring in kpc

• total_mass (float) – Total mass of the Gaussian ring component

Returns:

potl_grad – Potential gradient at each given R

Return type:

float or array

Notes

This function determines the potential gradient as a function of radius for a massive Gaussian ring component with a total mass, total_mass, and a ring peak radius to ring FWHM ratio, invh. This uses numerically calculated lookup tables.

read_ring_table()