Relic galaxy analogues in TNG50 simulation: the formation pathways of surviving red nuggets in a cosmological simulation

ABSTRACT Relic galaxies are massive compact quiescent that formed at high-redshift and remained almost unchanged since then. In this work, we search for analogues to relic in the TNG50 cosmological simulations understand formation test ability of reproduce such rare objects. Using stellar mass, age, radius, quiescence, assembly criteria, find five subhaloes could be potential analogues. We compare their properties with other constraints imposed by a sample 13 observed galaxies. one analogue simultaneously satisfies most available observational constraints, as metallicity morphology. It also shows similarities confirmed NGC 1277, regarding environment dark matter fraction. By taking into account degree relicness, second may considered. However, central parts brightness density profiles less steep than real galaxies, possibly due limited numerical resolution. identify two pathways depending on environment: they either have remaining gas stripped during infall cluster z ? 1.2 or consume it before > 1.5. They then deprived significant star formation, leaving populations unaltered last 9 Gyr. progenitors ? 4 inhabit more haloes similar mass 0.