An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A selection effect in observational astronomy. If a sample of objects (galaxies, quasars, stars, etc.) is flux-limited, then the observer will see an increase in average luminosity with distance, because the less luminous sources at large distances will not be detected.

Named after the Swedish astronomer Gunnar Malmquist (1893-1982); → bias.