Due to their extreme luminosities, gamma-ray bursts (GRBs) can be detected in hostile
regions of galaxies, nearby and at very high redshift, making them important cosmological
probes. The investigation of galaxies hosting long-duration GRBs (whose progenitor is a
massive star) demonstrated their connection to star formation. Still, the link to the
total galaxy population is controversial, mainly because of the small-number statistics:
~1, 100 are the GRBs detected so far, ~280 those with measured redshift, and
~70 the hosts studied in detail. These are typically low-redshift
(z < 1.5), low luminosity, metal poor, and star-forming galaxies. On
the other hand, at 1.5 < z < 4, massive, metal rich and dusty,
interacting galaxies are not uncommon. The most distant population
(z > 4) is poorly explored, but the deep limits reached point towards
very small and star-forming objects, similar to the low-z population.
This “back to the future” behavior is a natural consequence of the connection of long GRBs
to star formation in young regions of the universe.