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.

schechter_lf_magnitude

Sample magnitudes from a Schechter luminosity function.

Redshift

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

redshifts_from_comoving_density

Sample redshifts from a comoving density function.

schechter_lf_redshift

Sample redshifts from Schechter luminosity function.

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.

load_spectral_data

Load spectral data from a known source or a local file.

mag_ab

Compute absolute AB magnitudes from spectra and bandpasses.

magnitudes_from_templates

Compute AB magnitudes from template spectra.

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.

Functions

schechter_lf(redshift, M_star, phi_star, …)

Sample redshifts and magnitudes from a Schechter luminosity function.

skypy.galaxy.luminosity Module

Models of galaxy luminosities.

Functions

absolute_to_apparent_magnitude(…)

Convert absolute to apparent magnitude.

apparent_to_absolute_magnitude(…)

Convert apparent to absolute magnitude.

distance_modulus(redshift, cosmology)

Compute the distance modulus.

luminosity_from_absolute_magnitude(…[, …])

Converts absolute magnitudes to luminosities.

absolute_magnitude_from_luminosity(luminosity)

Converts luminosities to absolute magnitudes.

schechter_lf_magnitude(redshift, M_star, …)

Sample magnitudes from a Schechter luminosity function.

Variables

luminosity_in_band

Bandpass magnitude of reference luminosities.

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

redshifts_from_comoving_density(redshift, …)

Sample redshifts from a comoving density function.

schechter_lf_redshift(redshift, M_star, …)

Sample redshifts from Schechter luminosity function.

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.

load_spectral_data(name)

Load spectral data from a known source or a local file.

mag_ab(spectrum, bandpass[, redshift])

Compute absolute AB magnitudes from spectra and bandpasses.

magnitudes_from_templates(coefficients, …)

Compute AB magnitudes from template spectra.

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].