Galaxies (skypy.galaxy)

Introduction

Galaxy Properties

What follows are the physical properties of galaxies simulated by SkyPy, and the available models for each individual property.

Ellipticity

The following models are found in the skypy.galaxy.ellipticity package.

beta_ellipticity	Galaxy ellipticities sampled from a reparameterized beta distribution.
ryden04	Ellipticity distribution of Ryden (2004).

Luminosity

The following models are found in the skypy.galaxy.luminosity package.

herbel_luminosities

Model of Herbel et al (2017)

Redshift

The following models are found in the skypy.galaxy.redshift package.

herbel_redshift	Redshift following the Schechter luminosity function marginalised over luminosities following the Herbel et al.
smail	Redshifts following the Smail et al.

Size

The following models are found in the skypy.galaxy.size package.

angular_size	Angular size of a galaxy.
early_type_lognormal	Lognormal distribution for early-type galaxies.
late_type_lognormal	Lognormal distribution for late-type galaxies.
linear_lognormal	Lognormal distribution with linear mean.

Spectrum

The following models are found in the skypy.galaxy.spectrum package.

dirichlet_coefficients	Dirichlet-distributed SED coefficients.
kcorrect_spectra	Flux densities of galaxies.

Stellar mass

The following models are found in the skypy.galaxy.stellar_mass package.

schechter_smf

Stellar masses following the Schechter mass function [Rb238126a32b3-1].

Reference/API

skypy.galaxy Package

This module contains methods that model the intrinsic properties of galaxy populations.

skypy.galaxy.luminosity Module

Models of galaxy luminosities.

Functions

herbel_luminosities(redshift, alpha, a_m, b_m)

Model of Herbel et al (2017)

skypy.galaxy.ellipticity Module

Galaxy ellipticity module.

This module provides facilities to sample the ellipticities of galaxies.

Functions

beta_ellipticity(e_ratio, e_sum[, size])	Galaxy ellipticities sampled from a reparameterized beta distribution.
ryden04(mu_gamma, sigma_gamma, mu, sigma[, size])	Ellipticity distribution of Ryden (2004).

skypy.galaxy.redshift Module

Galaxy redshift module.

This module provides facilities to sample galaxy redshifts using a number of models.

Functions

herbel_redshift(alpha, a_phi, b_phi, a_m, …)	Redshift following the Schechter luminosity function marginalised over luminosities following the Herbel et al.
smail(z_median, alpha, beta[, size])	Redshifts following the Smail et al.

skypy.galaxy.size Module

Galaxy size module.

This modules computes the angular size of galaxies from their physical size.

Functions

angular_size(physical_size, redshift, cosmology)	Angular size of a galaxy.
early_type_lognormal(magnitude, a, b, M0, …)	Lognormal distribution for early-type galaxies.
late_type_lognormal(magnitude, alpha, beta, …)	Lognormal distribution for late-type galaxies.
linear_lognormal(magnitude, a_mu, b_mu, sigma)	Lognormal distribution with linear mean.

skypy.galaxy.spectrum Module

Galaxy spectrum module.

Functions

dirichlet_coefficients(redshift, alpha0, alpha1)	Dirichlet-distributed SED coefficients.
kcorrect_spectra(redshift, stellar_mass, …)	Flux densities of galaxies.

skypy.galaxy.stellar_mass Module

Models of galaxy stellar mass.

Functions

schechter_smf(alpha, m_star, x_min, x_max[, …])

Stellar masses following the Schechter mass function [Rb238126a32b3-1].