synthesizer.emission_models.stellar.pacman_model

A module defining the Pacman emission models.

This module defines the PacmanEmission and BimodalPacmanEmission classes which are used to define the emission models for the Pacman model. Both these models combine various differen spectra together to produce a final total emission spectrum.

The PacmanEmission model is used to define the emission model for a single population of stars. Including both intrinsic and attenuate emission, and if a dust emission model is given also dust emission. It includes the option to include escaped emission for a given escape fraction, and if a lyman alpha escape fraction is given, a more sophisticated nebular emission model is used, including line and nebuluar continuum emission.

The BimodalPacmanEmission model is similar to the PacmanEmission model but splits the emission into a young and old population.

The Charlot & Fall (2000) model if a special of the BimodalPacmanEmission model and is also included. This model is identical to the BimodalPacmanEmission model but with a fixed age pivot of 10^7 Myr and no escaped emission.

Example:

To create a PacmanEmission model for a grid with a V-band optical depth of
0.1 and a dust curve, one would do the following:

dust_curve = PowerLaw(...)
model = PacmanEmission(grid, 0.1, dust_curve)

To create a CharlotFall2000 model, you can use the following code:

tau_v_ism = 0.5
tau_v_birth = 0.5
dust_curve_ism = PowerLaw(...)
dust_curve_birth = PowerLaw(...)
age_pivot = 7 * dimensionless
dust_emission_ism = BlackBody(...)
dust_emission_birth = GreyBody(...)
model = CharlotFall2000(
    grid,
    tau_v_ism,
    tau_v_birth,
    dust_curve_ism,
    dust_curve_birth,
    age_pivot,
    dust_emission_ism,
    dust_emission_birth,
)

Classes

class synthesizer.emission_models.stellar.pacman_model.BimodalPacmanEmission(grid, tau_v_ism, tau_v_birth, dust_curve_ism, dust_curve_birth, age_pivot=unyt_quantity(7, 'dimensionless'), dust_emission_ism=None, dust_emission_birth=None, fesc=0.0, fesc_ly_alpha=1.0, label=None, stellar_dust=True, **kwargs)[source]

A class defining the Pacman model split into young and old populations.

This model defines both intrinsic and attenuated steller emission with or without dust emission. It also includes the option to include escaped emission for a given escape fraction. If a lyman alpha escape fraction is given, a more sophisticated nebular emission model is used, including line and nebuluar continuum emission.

All spectra produced have a young, old and combined component. The split between young and old is by default 10^7 Myr but can be changed with the age_pivot argument.

This model will always produce:
  • young_incident: the stellar emission incident onto the ISM for the

    young population.

  • old_incident: the stellar emission incident onto the ISM for the old

    population.

  • incident: the stellar emission incident onto the ISM for the

    combined population.

  • young_intrinsic: the intrinsic emission for the young population.

  • old_intrinsic: the intrinsic emission for the old population.

  • intrinsic: the intrinsic emission for the combined population.

  • young_attenuated_nebular: the nebular emission attenuated by dust

    for the young population.

  • young_attenuated_ism: the intrinsic emission attenuated by dust for

    the young population.

  • young_attenuated: the intrinsic emission attenuated by dust for the

    young population.

  • old_attenuated: the intrinsic emission attenuated by dust for the old

    population.

if grid.reprocessed is True:
  • young_transmitted: the stellar emission transmitted through the ISM

    for the young population.

  • old_transmitted: the stellar emission transmitted through the ISM for

    the old population.

  • transmitted: the stellar emission transmitted through the ISM for the

    combined population.

  • young_nebular: the stellar emisison from nebulae for the young

    population.

  • old_nebular: the stellar emisison from nebulae for the old

    population.

  • nebular: the stellar emisison from nebulae for the combined

    population.

  • young_reprocessed: the stellar emission reprocessed by the ISM for

    the young population.

  • old_reprocessed: the stellar emission reprocessed by the ISM for the

    old population.

  • reprocessed: the stellar emission reprocessed by the ISM for the

    combined population.

if fesc > 0.0:
  • young_escaped: the incident emission that completely escapes the ISM

    for the young population.

  • old_escaped: the incident emission that completely escapes the ISM

    for the old population.

  • escaped: the incident emission that completely escapes the ISM for

    the combined population.

  • young_emergent: the emission which emerges from the stellar

    population, including any escaped emission for the young population.

  • old_emergent: the emission which emerges from the stellar population,

    including any escaped emission for the old population.

  • emergent: the emission which emerges from the stellar population,

    including any escaped emission for the combined population.

if dust_emission is not None:
  • young_dust_emission_birth: the emission from dust for the young

    population.

  • young_dust_emission_ism: the emission from dust for the young

    population.

  • young_dust_emission: the emission from dust for the young population.

  • old_dust_emission: the emission from dust for the old population.

  • dust_emission: the emission from dust for the combined population.

  • young_total: the final total combined emission for the young

    population.

  • old_total: the final total combined emission for the old population.

  • total: the final total combined emission for the combined population.

grid

The grid object.

Type:

synthesizer.grid.Grid

tau_v_ism

The V-band optical depth for the ISM.

Type:

float

tau_v_birth

The V-band optical depth for the nebular.

Type:

float

dust_curve_ism

The dust curve for the ISM.

Type:

synthesizer.dust.DustCurve

dust_curve_birth

The dust curve for the nebular.

Type:

synthesizer.dust.DustCurve

age_pivot

The age pivot between young and old populations, expressed in terms of log10(age) in Myr.

Type:

unyt.unyt_quantity

dust_emission_ism

The dust emission for the ISM.

Type:

synthesizer.dust.EmissionModel

dust_emission_birth

The dust emission for the nebular.

Type:

synthesizer.dust.EmissionModel

fesc

The escape fraction.

Type:

float

fesc_ly_alpha

The Lyman alpha escape fraction.

Type:

float

Examples using synthesizer.emission_models.stellar.pacman_model.BimodalPacmanEmission

Camels example

Camels example

Generate parametric galaxy SED

Generate parametric galaxy SED
class synthesizer.emission_models.stellar.pacman_model.CharlotFall2000(grid, tau_v_ism, tau_v_birth, dust_curve_ism, dust_curve_birth, age_pivot=unyt_quantity(7, 'dimensionless'), dust_emission_ism=None, dust_emission_birth=None, label=None, stellar_dust=True, **kwargs)[source]

The Charlot & Fall (2000) emission model.

This emission model is based on the Charlot & Fall (2000) model, which describes the emission from a galaxy as a combination of emission from a young stellar population and an old stellar population. The dust attenuation for each population can be different, and dust emission can be optionally included.

This model is a simplified version of the BimodalPacmanEmission model, so in reality is just a wrapper around that model. The only difference is that there is no option to specify an escape fraction.

grid

The grid object.

Type:

synthesizer.grid.Grid

tau_v_ism

The V-band optical depth for the ISM.

Type:

float

tau_v_birth

The V-band optical depth for the nebular.

Type:

float

dust_curve_ism

The dust curve for the ISM.

Type:

synthesizer.dust.DustCurve

dust_curve_birth

The dust curve for the nebular.

Type:

synthesizer.dust.DustCurve

age_pivot

The age pivot between young and old populations, expressed in terms of log10(age) in Myr.

Type:

unyt.unyt_quantity

dust_emission_ism

The dust emission model for the ISM.

Type:

synthesizer.dust.EmissionModel

dust_emission_birth

The dust emission model for the nebular.

Type:

synthesizer.dust.EmissionModel

Examples using synthesizer.emission_models.stellar.pacman_model.CharlotFall2000

Camels example

Camels example

Generate parametric galaxy SED

Generate parametric galaxy SED
class synthesizer.emission_models.stellar.pacman_model.PacmanEmission(grid, tau_v, dust_curve=<synthesizer.emission_models.attenuation.dust.PowerLaw object>, dust_emission=None, fesc=0.0, fesc_ly_alpha=1.0, label=None, stellar_dust=True, **kwargs)[source]

A class defining the Pacman model.

This model defines both intrinsic and attenuated steller emission with or without dust emission. It also includes the option to include escaped emission for a given escape fraction. If a lyman alpha escape fraction is given, a more sophisticated nebular emission model is used, including line and nebuluar continuum emission.

This model will always produce:

  • incident: the stellar emission incident onto the ISM.

  • intrinsic: the intrinsic emission (when grid.reprocessed is False

    this is the same as the incident emission).

  • attenuated: the intrinsic emission attenuated by dust.

if grid.reprocessed is True:

  • transmitted: the stellar emission transmitted through the ISM.

  • nebular: the stellar emisison from nebulae.

  • reprocessed: the stellar emission reprocessed by the ISM.

if fesc > 0.0:

  • escaped: the incident emission that completely escapes the ISM.

  • emergent: the emission which emerges from the stellar population,

    including any escaped emission.

if dust_emission is not None:

  • dust_emission: the emission from dust.

  • total: the final total combined emission.

grid

The grid object

Type:

synthesizer.grid.Grid

tau_v

The V-band optical depth

Type:

float

dust_curve

The dust curve

Type:

synthesizer.dust.DustCurve

dust_emission

The dust emission

Type:

synthesizer.dust.EmissionModel

fesc

The escape fraction

Type:

float

fesc_ly_alpha

The Lyman alpha escape fraction

Type:

float

Examples using synthesizer.emission_models.stellar.pacman_model.PacmanEmission

SC-SAM example

SC-SAM example

Plot spectra example

Plot spectra example

Photometry example

Photometry example

Generate parametric observed SED

Generate parametric observed SED

An example showing how to scale a galaxy’s mass by luminosity/flux.

An example showing how to scale a galaxy's mass by luminosity/flux.

Generate parametric galaxy SED

Generate parametric galaxy SED
class synthesizer.emission_models.stellar.pacman_model.ScreenEmission(grid, tau_v, dust_curve, dust_emission=None, label=None, **kwargs)[source]

The ScreenEmission model.

This emission model is a simple dust screen model, where the dust is assumed to be in a screen in front of the stars. The dust curve and emission model can be specified, but the escape fraction is always zero.

This model is a simplified version of the PacmanEmission model, so in reality is just a wrapper around that model. The only difference is that fesc and fesc_ly_alpha are zero by definition.

grid

The grid object.

Type:

synthesizer.grid.Grid

tau_v

The V-band optical depth.

Type:

float

dust_curve

The dust curve.

Type:

synthesizer.dust.DustCurve

dust_emission

The dust emission model.

Type:

synthesizer.dust.EmissionModel