Bibcode
Vazdekis, A.; Balcells, M.; Ferré-Mateu, A.; Trujillo, I.; Sánchez-Blázquez, Patricia
Bibliographical reference
The Astrophysical Journal Letters, Volume 780, Issue 2, article id. L20, 6 pp. (2014).
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1
2014
Citations
110
Refereed citations
103
Description
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.
Related projects
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
Ignacio
Martín Navarro