  Compact groups of galaxies are devised as extreme environments where
interactions may drive galaxy evolution. In this work, we analysed whether the
luminosities of galaxies inhabiting compact groups differ from those of
galaxies in loose galaxy groups. We computed the luminosity functions of galaxy
populations inhabiting a new sample of 1412 Hickson-like compact groups of
galaxies identified in the Sloan Digital Sky Survey Data Release 16. We
observed a characteristic absolute magnitude for galaxies in compact groups
brighter than that observed in the field or loose galaxy systems. We also
observed a deficiency of faint galaxies in compact groups in comparison with
loose systems. Our analysis showed that the brightening is mainly due to
galaxies inhabiting the more massive compact groups. In contrast to what is
observed in loose systems where only the luminosities of Red (and Early)
galaxies show a dependency with group mass, luminosities of Red and Blue (also
Early and Late) galaxies in compact groups are affected similarly as a function
of group virial mass. When using Hubble types, we observed that Elliptical
galaxies in compact groups are the brightest galaxy population, and groups
dominated by an Elliptical galaxy also display the brightest luminosities in
comparison with those dominated by Spiral galaxies. Moreover, we show that the
general luminosity trends can be reproduced using a mock catalogue obtained
from a semi-analytical model of galaxy formation. These results suggest that
the inner extreme environment in compact groups prompts a different
evolutionary history for their galaxies.
