DiskBulge

class dysmalpy.models.DiskBulge(invq_disk=5, invq_bulge=1, noord_flat=False, light_component='disk', gas_component='disk', baryon_type='gas+stars', **kwargs)[source]

Bases: MassModel, _LightMassModel

Mass distribution with a disk and bulge

Parameters:

total_mass (float) – Log10 of the combined disk and bulge in solar units
r_eff_disk (float) – Effective radius of the disk in kpc
n_disk (float) – Sersic index of the disk
r_eff_bulge (float) – Effective radius of the bulge
n_bulge (float) – Sersic index of the bulge
bt (float) – Bulge-to-total mass ratio
invq_disk (float) – Effective radius to effective height ratio for the disk
invq_bulge (float) – Effective radius to effective height ratio for the bulge
noord_flat (bool) – If True, use circular velocity profiles derived in Noordermeer 2008. If False, circular velocity is derived through v_circular
light_component ({'disk', 'bulge', 'total'}) – Which component to use as the flux profile
gas_component ({'disk', 'total'}) – Which component contributes to dlnrhogas/dlnr
baryon_type ({'gas+stars', 'stars', 'gas'}) – What type of baryons are included. Used for dlnrhogas/dlnr

Notes

This model is the combination of 2 components, a disk and bulge, each described by a Sersic. The model is parametrized such that the B/T is a free parameter rather than the individual masses of the disk and bulge.

Attributes Summary

`bt`
`mass_to_light`
`n_bulge`
`n_disk`
`noord_flat`
`param_names`	Names of the parameters that describe models of this type.
`r_eff_bulge`
`r_eff_disk`
`total_mass`
`tracer`

Methods Summary

`circular_velocity`(r)	Total circular velocity as a function of radius
`circular_velocity_bulge`(r)	Circular velocity of the bulge as a function of radius
`circular_velocity_disk`(r)	Circular velocity of the disk as a function of radius
`dlnrhogas_dlnr`(r)	Asymmetric drift term for the combined disk and bulge
`dlnrhogas_dlnr_bulge`(r)
`dlnrhogas_dlnr_disk`(r)
`enclosed_mass`(r)	Disk+Bulge total enclosed mass
`enclosed_mass_bulge`(r)	Enclosed mass of the bulge component
`enclosed_mass_disk`(r)	Enclosed mass of the disk component
`evaluate`(r, total_mass, r_eff_disk, n_disk, ...)	Disk+Bulge mass surface density
`light_profile`(r)	Conversion from mass to light as a function of radius
`projected_enclosed_mass`(r)
`projected_enclosed_mass_bulge`(r)
`projected_enclosed_mass_disk`(r)
`rhogas`(r)	Mass density as a function of radius (if noord_flat; otherwise surface density)
`rhogas_bulge`(r)	Mass density of the bulge as a function of radius (if noord_flat; otherwise surface density)
`rhogas_disk`(r)	Mass density of the disk as a function of radius (if noord_flat; otherwise surface density)
`velocity_profile`(r, modelset)	Total rotational velocity due to the disk+bulge
`velocity_profile_bulge`(r, modelset)	Rotational velocity due to the bulge
`velocity_profile_disk`(r, modelset)	Rotational velocity due to the disk

Attributes Documentation

bt = DysmalParameter('bt', value=0.2, bounds=(0, 1), prior=<dysmalpy.parameters.UniformPrior object>)

mass_to_light = DysmalParameter('mass_to_light', value=1.0, fixed=True, prior=<dysmalpy.parameters.UniformPrior object>)

n_bulge = DysmalParameter('n_bulge', value=4.0, fixed=True, bounds=(0, 8), prior=<dysmalpy.parameters.UniformPrior object>)

n_disk = DysmalParameter('n_disk', value=1.0, fixed=True, bounds=(0, 8), prior=<dysmalpy.parameters.UniformPrior object>)

noord_flat

param_names = ('total_mass', 'r_eff_disk', 'n_disk', 'r_eff_bulge', 'n_bulge', 'bt', 'mass_to_light')

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.

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

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

total_mass = DysmalParameter('total_mass', value=10.0, bounds=(5, 14), prior=<dysmalpy.parameters.UniformPrior object>)

tracer = 'mass'

Methods Documentation

circular_velocity(r)[source]

Total circular velocity as a function of radius

Parameters:: r (float or array) – Radii at which to calculate the circular velocity in kpc
Returns:: vcirc – Circular velocity in km/s
Return type:: float or array

circular_velocity_bulge(r)[source]

Circular velocity of the bulge as a function of radius

Parameters:: r (float or array) – Radii at which to calculate the circular velocity
Returns:: vcirc – Circular velocity in km/s
Return type:: float or array

circular_velocity_disk(r)[source]

Circular velocity of the disk as a function of radius

Parameters:: r (float or array) – Radii at which to calculate the circular velocity
Returns:: vcirc – Circular velocity in km/s
Return type:: float or array

dlnrhogas_dlnr(r)[source]

Asymmetric drift term for the combined disk and bulge

Parameters:: r (float or array) – Radius in kpc
Returns:: log_drhodr – Log surface density derivative as a function or radius
Return type:: float or array

dlnrhogas_dlnr_bulge(r)[source]

dlnrhogas_dlnr_disk(r)[source]

enclosed_mass(r)[source]

Disk+Bulge total enclosed mass

Parameters:: r (float or array) – Radii at which to calculate the enclosed mass
Returns:: menc – Enclosed mass profile
Return type:: float or array

enclosed_mass_bulge(r)[source]

Enclosed mass of the bulge component

Parameters:: r (float or array) – Radii at which to calculate the enclosed mass
Returns:: menc – Enclosed mass profile
Return type:: float or array

enclosed_mass_disk(r)[source]

Enclosed mass of the disk component

Parameters:: r (float or array) – Radii at which to calculate the enclosed mass
Returns:: menc – Enclosed mass profile
Return type:: float or array

static evaluate(r, total_mass, r_eff_disk, n_disk, r_eff_bulge, n_bulge, bt, mass_to_light)[source]: Disk+Bulge mass surface density

light_profile(r)[source]

Conversion from mass to light as a function of radius

Parameters:: r (float or array) – Radii at which to calculate the enclosed mass
Returns:: light – Relative line flux as a function of radius
Return type:: float or array

Notes

The resulting light profile depends on what DiskBulge.light_component is set to. If ‘disk’ or ‘bulge’ then only the mass associated with the disk or bulge will be converted into light. If ‘total’, then both components will be used.

projected_enclosed_mass(r)[source]

projected_enclosed_mass_bulge(r)[source]

projected_enclosed_mass_disk(r)[source]

rhogas(r)[source]

Mass density as a function of radius (if noord_flat; otherwise surface density)

Parameters:: r (float or array) – Radii at which to calculate the enclosed mass
Returns:: dens – Mass density at r in units of Msun/kpc^3 (if noord_flat; otherwise surface density)
Return type:: float or array

rhogas_bulge(r)[source]

Mass density of the bulge as a function of radius (if noord_flat; otherwise surface density)

Parameters:: r (float or array) – Radii at which to calculate the enclosed mass
Returns:: dens – Mass density at r in units of Msun/kpc^3 (if noord_flat; otherwise surface density)
Return type:: float or array

rhogas_disk(r)[source]

Mass density of the disk as a function of radius (if noord_flat; otherwise surface density)

Parameters:: r (float or array) – Radii at which to calculate the enclosed mass
Returns:: dens – Mass density at r in units of Msun/kpc^3 (if noord_flat; otherwise surface density)
Return type:: float or array

velocity_profile(r, modelset)[source]

Total rotational velocity due to the disk+bulge

Parameters:

r (float or array) – Radii at which to calculate the circular velocity in kpc
modelset (ModelSet) – Full ModelSet this component belongs to

Returns:

vrot – Rotational velocity in km/s

Return type:

float or array

Notes

This method requires a ModelSet input to be able to apply the pressure support correction due to the gas turbulence.

velocity_profile_bulge(r, modelset)[source]

Rotational velocity due to the bulge

Parameters:

r (float or array) – Radii at which to calculate the circular velocity in kpc
modelset (ModelSet) – Full ModelSet this component belongs to

Returns:

vrot – Rotational velocity in km/s

Return type:

float or array

Notes

This method requires a ModelSet input to be able to apply the pressure support correction due to the gas turbulence.

velocity_profile_disk(r, modelset)[source]

Rotational velocity due to the disk

Parameters:

r (float or array) – Radii at which to calculate the circular velocity in kpc
modelset (ModelSet) – Full ModelSet this component belongs to

Returns:

vrot – Rotational velocity in km/s

Return type:

float or array

Notes

This method requires a ModelSet input to be able to apply the pressure support correction due to the gas turbulence.