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THE EVOLUTION OF CENTRAL GROUP GALAXIES IN HYDRODYNAMICAL SIMULATIONS
- Source :
- The Astrophysical Journal. 709:218-240
- Publication Year :
- 2009
- Publisher :
- American Astronomical Society, 2009.
-
Abstract
- We trace the evolution of central galaxies in three ~10^13 M_sun galaxy groups simulated at high resolution in cosmological hydrodynamical simulations. The evolution in the group potential leads, at z=0, to central galaxies that are massive, gas-poor early-type systems supported by stellar velocity dispersion resembling either elliptical or S0 galaxies. Their z~2-2.5 main progenitors are massive M* ~ 3-10 x 10^10 M_sun, star forming (20-60 M_sun/yr) galaxies which host substantial reservoirs of cold gas (~5 x 10^9 M_sun) in extended gas disks. Our simulations thus show that star forming galaxies observed at z~2 are likely the main progenitors of central galaxies in galaxy groups at z=0. Their central stellar densities stay approximately constant from z~1.5 down to z=0. Instead, the galaxies grow inside-out, by acquiring a stellar envelope outside the innermost ~2 kpc. Consequently the density within the effective radius decreases by up to two orders of magnitude. Both major and minor mergers contribute to most of the mass accreted outside the effective radius and thus drive the evolution of the half-mass radii. In one of the three simulated groups the short central cooling time leads to a dramatic rejuvenation of the central group galaxy at z<br />28 pages, 23 figures, 9 tables, accepted to APJ (revised to match accepted version)
- Subjects :
- Effective radius
Physics
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
010308 nuclear & particles physics
Star formation
FOS: Physical sciences
Velocity dispersion
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
01 natural sciences
Galaxy
Accretion (astrophysics)
Space and Planetary Science
Galaxy group
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Earth and Planetary Astrophysics
Halo
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Order of magnitude
Astrophysics - Cosmology and Nongalactic Astrophysics
Subjects
Details
- ISSN :
- 15384357 and 0004637X
- Volume :
- 709
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....052cd1597fc9d6c756f3fb913f784c87