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luminosity function

(function giving number of stars or galaxies at different luminosities)

A luminosity function is an empirical unnormalized probability density function that yields the number of stars or galaxies at each given luminosity.

A common form is the Schechter luminosity function for galaxies (aka Schechter function, an example of a galaxy luminosity function), a "modified" power law providing a format for such functions:

n(x)dx = ΦSunxae-xdx

Some typical values of the plug-in parameters:

Other variations of luminosity functions are globular cluster luminosity functions, galaxy cluster luminosity functions, and luminosity functions of particular bands, or lines, or the lines of a specific molecule (e.g., carbon monoxide).

Luminosity functions also are assumed to evolve, e.g., to vary with redshift.


Referenced by:
conditional luminosity function (CLF)
initial mass function (IMF)
luminosity density
planetary nebula luminosity function (PNLF)