As early as 10 Gyr ago, galaxies with more than 10^11 Msun in stars already
existed. While most of these massive galaxies must have subsequently
transformed through on-going star formation and mergers with other galaxies, a
small fraction (<0.1%) may have survived untouched till today. Searches for
such relic galaxies, useful windows to explore the early Universe, have been
inconclusive to date: galaxies with masses and sizes like those observed at
high redshift (M*>10^11 Msun; Re<1.5 kpc) have been found in the local
Universe, but their stars are far too young for the galaxy to be a relic
galaxy. This paper explores the first case of a nearby galaxy, NGC1277 (in the
Perseus cluster at a distance of 73 Mpc), which fulfills all the criteria to be
considered a relic galaxy. Using deep optical spectroscopy, we derive the star
formation history along the structure of the galaxy: the stellar populations
are uniformly old (>10 Gyr) with no evidence for more recent star formation
episodes. The metallicity of their stars is super-solar ([Fe/H]=0.20+-0.04) and
alpha enriched ([alpha/Fe]=0.4+-0.1). This suggests a very short formation time
scale for the bulk of stars of this galaxy. This object also rotates very fast
(Vrot~300 km/s) and has a large velocity dispersion (sigma>300 km/s). NGC1277
will allow future explorations in full detail of properties such as the
structure, internal dynamics, metallicity, dust content and initial mass
function at around 10-12 Gyr back in time when the first massive galaxies were
built.Comment: 4 figures; Accepted for publication at ApJ Letter
