X-ray luminosity function

The term X-ray luminosity function and abbreviation XLF are currently used for functions indicating some aspect of X-ray luminosity, probably typically an indication of the relative number of sources with each luminosity analogous to an initial mass function or luminosity function. Such a function is likely to be for some specified class of sources, e.g., the type of source (e.g., AGN versus X-ray-producing stars within the Milky Way) or age, such as by redshift of AGN, or could indicate the luminosity after obscuration by X-ray-opaque material or the presumed X-ray luminosity behind it.