schechter_lf_magnitude

skypy.galaxy.luminosity.schechter_lf_magnitude(redshift, M_star, alpha, m_lim, cosmology, size=None, x_max=1000.0, resolution=1000)

Sample magnitudes from a Schechter luminosity function.

Given a list of galaxy redshifts, and an apparent magnitude limit, sample galaxy absolute magnitudes from a Schechter luminosity function.

Parameters

redshiftarray_like

Galaxy redshifts for which to sample magnitudes.

M_stararray_like or function

Characteristic absolute magnitude, either constant, or an array with values for each galaxy, or a function of galaxy redshift.

alphaarray_like or function

Schechter function index, either a constant, or an array of values for each galaxy, or a function of galaxy redshift.

m_limfloat

Apparent magnitude limit.

cosmologyCosmology, optional

Cosmology object for converting apparent and absolute magnitudes. If no cosmology is given, the default cosmology is used.

sizeint, optional

Explicit size for the sampling. If not given, one magnitude is sampled for each redshift.

Returns

magnitudearray_like

Absolute magnitude sampled from a Schechter luminosity function for each input galaxy redshift.

Examples

Sample a number of blue (alpha = -1.3, M_star = -20.5) galaxy magnitudes brighter than m = 22.0 around redshift 0.5.

>>> import numpy as np
>>> from skypy.galaxy.luminosity import schechter_lf_magnitude
>>> z = np.random.uniform(4.9, 5.1, size=20)
>>> M = schechter_lf_magnitude(z, -20.5, -1.3, 22.0)