Knowra Galaxy luminosity function Galaxy luminosity function A statistical distribution giving the number density of galaxies as a function of luminosity. Its shape summarizes how common faint and bright galaxies are in a population.
Schechter function : A formula commonly used to describe galaxy luminosity and mass distributions, with a power law at the faint end and an exponential bright-end cutoff. Its parameters summarize the characteristic luminosity, faint-end slope, and overall normalization.
Galaxy formation : The physical processes by which gas, stars, and dark matter assemble into galaxies. Predicted galaxy counts by brightness provide a test of how galaxies form and evolve.
Hα luminosity function : A distribution of galaxies by luminosity in the hydrogen-alpha emission line. It traces star-forming galaxies through a line emitted by ionized hydrogen.
Reionization feedback : The suppression of gas accretion and star formation in small galaxies as the universe became ionized. It may explain why models predict more faint galaxies than observations find.
Absolute magnitude : A measure of an object's intrinsic brightness, defined as its apparent magnitude at a standard distance of 10 parsecs. Galaxy luminosity functions are often plotted in magnitudes rather than physical luminosity.
Galaxy evolution : Changes in galaxies' structure, stellar content, gas, and activity over cosmic time. Comparing luminosity functions across epochs reveals how galaxy populations change.
Lyα luminosity function : A distribution of galaxies by luminosity in the hydrogen Lyman-alpha emission line. It is used to study star-forming galaxies, especially at high redshift.
Active galactic nucleus feedback : The influence of energy and matter released by accreting supermassive black holes on their host galaxies. It can suppress bright-end galaxy growth and shape the abundance of luminous systems.
Luminosity distance : The distance defined by the inverse-square relation between an object's luminosity and its observed flux. Converting measured fluxes into luminosities requires estimating this distance.
Cosmic star-formation history : The history of the universe's star-formation rate per unit volume over cosmic time. Luminosity functions help estimate star formation across galaxies and epochs.
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