schechter_lf

skypy.galaxies.schechter_lf(redshift, M_star, phi_star, alpha, m_lim, sky_area, cosmology, noise=True)[source] [edit on github]

Sample redshifts and magnitudes from a Schechter luminosity function.

Sample the redshifts and magnitudes of galaxies following a Schechter luminosity function with potentially redshift-dependent parameters, limited by an apparent magnitude m_lim, for a sky area sky_area.

Parameters
redshiftarray_like

Input redshift grid on which the Schechter function parameters are evaluated. Galaxies are sampled over this redshift range.

M_stararray_like or function

Characteristic absolute magnitude of the Schechter function. Can be a single value, an array of values for each redshift, or a function of redshift.

phi_stararray_like or function

Normalisation of the Schechter function. Can be a single value, an array of values for each redshift, or a function of redshift.

alphaarray_like or function

Schechter function power law index. Can be a single value, an array of values for each redshift, or a function of redshift.

m_limfloat

Limiting apparent magnitude.

sky_areaQuantity

Sky area over which galaxies are sampled. Must be in units of solid angle.

cosmologyCosmology

Cosmology object to convert apparent to absolute magnitudes.

noisebool, optional

Poisson-sample the number of galaxies. Default is True.

Returns
redshifts, magnitudestuple of array_like

Redshifts and magnitudes of the galaxy sample described by the Schechter luminosity function.

Notes

Effectively calls schechter_lf_redshift and schechter_lf_magnitude internally and returns the tuple of results.