Bibcode
Vazdekis, A.; Balcells, M.; Ferré-Mateu, A.; Trujillo, I.; Sánchez-Blázquez, Patricia
Referencia bibliográfica
The Astrophysical Journal Letters, Volume 780, Issue 2, article id. L20, 6 pp. (2014).
Fecha de publicación:
1
2014
Número de citas
110
Número de citas referidas
103
Descripción
As early as 10 Gyr ago, galaxies with more than 1011 M
☉ of 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 (lsim0.1%)
may have survived untouched until 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 sstarf >~ 1011 M
☉ 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, NGC
1277 (at a distance of 73 Mpc in the Perseus galaxy cluster), which
fulfills many 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 with a smooth decline toward the outer regions) and
α-enriched ([α/Fe] = 0.4 ± 0.1). This suggests a very
short formation time scale for the bulk of the stars in this galaxy.
This object also rotates very fast (V rot ~ 300 km
s–1) and has a large central velocity dispersion
(σ > 300 km s–1). NGC 1277 allows the
exploration in full detail of properties such as the structure, internal
dynamics, metallicity, and initial mass function as they were at ~10-12
Gyr ago when the first massive galaxies were built.
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