NoordFlat

class dysmalpy.models.NoordFlat(n=None, invq=None)

Bases: object

Class to handle circular velocities / enclosed mass profiles for a thick Sersic component.

Lookup tables are numerically calculated from the derivations provided in Noordermeer 2008 which properly accounted for the thickness of the mass component.

The lookup table provides rotation curves for Sersic components with n = 0.5 - 8 at steps of 0.1 and invq = [1, 2, 3, 4, 5, 6, 7, 8, 10, 20, 100]. If the given n and/or invq are not one of these values then the nearest ones are used.

References

Noordermeer 2008

Parameters:

• n (float) – Sersic index

• invq (float) – Sersic index

Attributes Summary

invq
n

Methods Summary

circular_velocity(r, r_eff, mass)	Calculate circular velocity for a thick Sersic component, by interpolating
dlnrho_dlnr(r, Reff[, interp_type])	Calculate log mass density gradient for a thick Sersic component, by interpolating.
enclosed_mass(r, r_eff, mass)	Calculate enclosed mass for a thick Sersic component, by interpolating
read_deprojected_sersic_table()
rho(r, Reff, total_mass[, interp_type])

Attributes Documentation

invq

n

Methods Documentation

circular_velocity(r, r_eff, mass)

Calculate circular velocity for a thick Sersic component, by interpolating

Parameters:

• r (float or array) – Radius or radii at which to calculate the circular velocity in kpc

• r_eff (float) – Effective radius of the Sersic component in kpc

• mass (float) – Total mass of the Sersic component

Returns:

vcirc – Circular velocity at each given r, in km/s

Return type:

float or array

Notes

This function determines the circular velocity as a function of radius for a Sersic component with a total mass, mass, Sersic index, n, and an effective radius to scale height ratio, invq. This uses lookup tables numerically calculated from the derivations provided in Noordermeer 2008 which properly account for the thickness of the mass component.

References

Noordermeer 2008

dlnrho_dlnr(r, Reff, interp_type='linear')

Calculate log mass density gradient for a thick Sersic component, by interpolating.

Can be used to determine an alternative pressure support correction.

References

Noordermeer 2008 Price et al. 2022

enclosed_mass(r, r_eff, mass)

Calculate enclosed mass for a thick Sersic component, by interpolating

Parameters:

• r (float or array) – Radius or radii at which to calculate the circular velocity in kpc

• r_eff (float) – Effective radius of the Sersic component in kpc

• mass (float) – Total mass of the Sersic component

Returns:

menc – Enclosed mass (in a sphere) at each given r, in solar masses

Return type:

float or array

Notes

This function determines the spherical enclosed mass as a function of radius for a Sersic component with a total mass, mass, Sersic index, n, and an effective radius to scale height ratio, invq. This uses lookup tables numerically calculated from the derivations provided in Noordermeer 2008 (as extended in Price et al. 2022) which properly account for the thickness of the mass component.

References

Noordermeer 2008 Price et al. 2022

read_deprojected_sersic_table()

rho(r, Reff, total_mass, interp_type='linear')