Expected Number of Massive Galaxy Relics in the Present Day Universe

Trujillo, I.; Quilis, V.
Bibliographical reference

The Astrophysical Journal Letters, Volume 773, Issue 1, article id. L8, 4 pp. (2013).

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8
2013
Number of authors
2
IAC number of authors
1
Citations
45
Refereed citations
41
Description
The number of present day massive galaxies that have survived untouched since their formation at high-z is an important observational constraint to the hierarchical galaxy formation models. Using three different semianalytical models based on the Millenium simulation, we quantify the expected fraction and number densities of the massive galaxies that form at z > 2 and have evolved in stellar mass less than 10% and 30%. We find that only a small fraction of the massive galaxies that already formed at z ~ 2 have remained almost unaltered since their formation (<2% with ΔM sstarf/M sstarf < 0.1 and <8% with ΔM sstarf/M sstarf < 0.3). These fractions correspond to the following number densities of massive relics in the present day universe: ~1.2 × 10–6 Mpc–3 for ΔM sstarf/M sstarf < 0.1 and ~5.7 × 10–6 Mpc–3 for ΔM sstarf/M sstarf < 0.3. The observed number of relic candidates found in the nearby universe is rather uncertain today (with uncertainties up to a factor of ~100), preventing us from establishing firm conclusions about the ability of current theoretical expectations to predict such an important number.
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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.
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