lfkit.photometry.conditional_lf_models module#

Conditional luminosity function model utilities.

This module provides conditional wrappers around existing LFKit luminosity function models.

A conditional luminosity function has the form Phi(M | x), where M is absolute magnitude and x is an external conditioning variable. The conditioning variable is intentionally generic. It may represent redshift, halo mass, environment, galaxy type, richness, stellar mass, or any other quantity.

This module does not implement HOD or halo-model machinery.

lfkit.photometry.conditional_lf_models.conditional_double_schechter(absolute_mag, condition, *, phi_star, m_star, alpha, beta, m_transition)[source]#

Evaluate a conditional double-power-law Schechter luminosity function.

Parameters:

  • absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute magnitude value(s).

  • condition (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Values of the conditioning variable.

  • phi_star (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Overall normalization. May be scalar, array-like, or callable of condition.

  • m_star (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Characteristic absolute magnitude. May be scalar, array-like, or callable of condition.

  • alpha (float) – Bright/intermediate faint-end slope parameter.

  • beta (float) – Additional faint-end slope modifier.

  • m_transition (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Transition magnitude. May be scalar, array-like, or callable of condition.

Returns:

Conditional double-power-law Schechter luminosity function values.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.conditional_lf_models.conditional_evolving_schechter(absolute_mag, condition, *, phi_model='linear_p', phi_kwargs=None, m_star_model='linear_q', m_star_kwargs=None, alpha_model='constant', alpha_kwargs=None)[source]#

Evaluate a conditional Schechter LF using LFKit parameter models.

This is the conditional LF analogue of evolving_schechter. The conditioning variable is passed to LFKit’s registered parameter models.

Parameters:

  • absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute magnitude value(s).

  • condition (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Values of the conditioning variable.

  • phi_model (str) – Evolution/condition model for phi_star.

  • phi_kwargs (Mapping[str, float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]] | None) – Keyword arguments passed to the selected phi_star model.

  • m_star_model (str) – Evolution/condition model for M_star.

  • m_star_kwargs (Mapping[str, float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]] | None) – Keyword arguments passed to the selected M_star model.

  • alpha_model (str) – Evolution/condition model for alpha.

  • alpha_kwargs (Mapping[str, float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]] | None) – Keyword arguments passed to the selected alpha model.

Returns:

Conditional Schechter luminosity function values.

Raises:

ValueError – If an unsupported parameter model is requested.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.conditional_lf_models.conditional_schechter(absolute_mag, condition, *, phi_star, m_star, alpha)[source]#

Evaluate a conditional Schechter luminosity function.

Parameters:

  • absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute magnitude value(s).

  • condition (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Values of the conditioning variable.

  • phi_star (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Schechter normalization. May be scalar, array-like, or callable of condition.

  • m_star (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Characteristic absolute magnitude. May be scalar, array-like, or callable of condition.

  • alpha (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Faint-end slope. May be scalar, array-like, or callable of condition.

Returns:

Conditional Schechter luminosity function values.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.conditional_lf_models.lognormal_conditional_lf(absolute_mag, condition, *, mean_absolute_mag, sigma_log_luminosity, amplitude=1.0)[source]#

Evaluate a lognormal conditional luminosity function in magnitudes.

Parameters:

  • absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute magnitude value(s).

  • condition (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Values of the conditioning variable.

  • mean_absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Mean absolute magnitude. May be scalar, array-like, or callable of condition.

  • sigma_log_luminosity (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Scatter in log10(L) at fixed condition. May be scalar, array-like, or callable of condition.

  • amplitude (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Non-negative amplitude of the component. May be scalar, array-like, or callable of condition.

Returns:

Lognormal conditional luminosity function values.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.conditional_lf_models.modified_schechter_conditional_lf(absolute_mag, condition, *, phi_star, m_star, alpha)[source]#

Evaluate a modified Schechter conditional luminosity function.

This uses a squared exponential cutoff in luminosity ratio instead of the standard Schechter exponential cutoff.

Parameters:

  • absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute magnitude value(s).

  • condition (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Values of the conditioning variable.

  • phi_star (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Component normalization.

  • m_star (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Characteristic absolute magnitude.

  • alpha (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Faint-end slope.

Returns:

Modified Schechter conditional luminosity function values.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.conditional_lf_models.two_component_conditional_lf(absolute_mag, condition, *, lognormal_mean_absolute_mag, lognormal_sigma_log_luminosity, modified_phi_star, modified_alpha, lognormal_amplitude=1.0, modified_m_star=None, modified_luminosity_fraction=0.562)[source]#

Evaluate the sum of lognormal and modified Schechter components.

Parameters:

  • absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute magnitude value(s).

  • condition (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Values of the conditioning variable.

  • lognormal_mean_absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Mean absolute magnitude of the lognormal component. May be scalar, array-like, or callable of condition.

  • lognormal_sigma_log_luminosity (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Scatter in log10(L) for the lognormal component. May be scalar, array-like, or callable of condition.

  • modified_phi_star (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Normalization of the modified Schechter component. May be scalar, array-like, or callable of condition.

  • modified_alpha (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Faint-end slope of the modified Schechter component. May be scalar, array-like, or callable of condition.

  • lognormal_amplitude (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Non-negative amplitude of the lognormal component. May be scalar, array-like, or callable of condition.

  • modified_m_star (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]] | None) – Characteristic absolute magnitude of the modified Schechter component. If omitted, it is derived from lognormal_mean_absolute_mag and modified_luminosity_fraction.

  • modified_luminosity_fraction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | Callable[[ndarray[tuple[Any, ...], dtype[float64]]], float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]]) – Ratio used to derive the modified Schechter characteristic luminosity from the lognormal mean luminosity when modified_m_star is omitted.

Returns:

Combined conditional luminosity function values.

Return type:

ndarray[tuple[Any, …], dtype[float64]]