Статья

The formation of massive, compact galaxies at z = 2 in the Illustris simulation

Sarah WellonsHarvard–Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USAPaul TorreyMassachusetts Institute of Technology, Cambridge, MA 02139, USAChung‐Pei MaUniversity of California Berkeley, Berkeley, CA 94720, USAVicente Rodríguez-GómezHarvard–Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USAMark VogelsbergerMassachusetts Institute of Technology, Cambridge, MA 02139, USAMariska KriekUniversity of California Berkeley, Berkeley, CA 94720, USAPieter van DokkumYale University, 260 Whitney Ave, New Haven, CT 06511, USAErica J. NelsonYale University, 260 Whitney Ave, New Haven, CT 06511, USAShy GenelDepartment of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027, USAAnnalisa PillepichHarvard–Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USAVolker SpringelHeidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg, GermanyDebora SijackiGregory F. SnyderSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USADylan NelsonHarvard–Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USALaura V. SalesHarvard–Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USALars HernquistHarvard–Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USA

2015en

ABI

Аннотация

Massive, quiescent galaxies at high redshift have been found to be considerably more compact than galaxies of similar mass in the local universe. How these compact galaxies formed has yet to be determined, though several progenitor populations have been proposed. Here we investigate the formation processes and quantify the assembly histories of such galaxies in Illustris, a suite of hydrodynamical cosmological simulations encompassing a sufficiently large volume to include rare objects, while simultaneously resolving the internal structure of galaxies. We select massive (∼1011 M⊙) and compact (stellar half-mass radius <2 kpc) galaxies from the simulation at z = 2. Within the Illustris suite, we find that these quantities are not perfectly converged, but are reasonably reliable for our purposes. The resulting population is composed primarily of quiescent galaxies, but we also find several star-forming compact galaxies. The simulated compact galaxies are similar to observed galaxies in star formation activity and appearance. We follow their evolution at high redshift in the simulation and find that there are multiple pathways to form these compact galaxies, dominated by two mechanisms: (i) intense, centrally concentrated starbursts generally triggered by gas-rich major mergers between z ∼ 2–4, reducing the galaxies’ half-mass radii by a factor of a few to below 2 kpc, and (ii) assembly at very early times when the universe was much denser; the galaxies formed compact and remained so until z ∼ 2.

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Идентификаторы

DOI: 10.1093/mnras/stv303

Цитирования и источники

Цитирований: 2Использованных источников: 0

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