HAL CCSD
Evolution of Compact and Fossil Groups of Galaxies from Semi-analytical Models of Galaxy Formation
Farhang, Amin
Khosroshahi, Habib G.
Mamon, Gary A.
Dariush, Ali. A.
Raouf, Mojtaba
Institut d'Astrophysique de Paris (IAP) ; Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
International audience
ISSN: 0004-637X
EISSN: 1538-4357
The Astrophysical Journal
American Astronomical Society
insu-03747473
https://insu.hal.science/insu-03747473
https://insu.hal.science/insu-03747473
The Astrophysical Journal, 2017, 840, ⟨10.3847/1538-4357/aa6b00⟩
ARXIV: 1704.00731
info:eu-repo/semantics/altIdentifier/arxiv/1704.00731
BIBCODE: 2017ApJ...840...58F
DOI: 10.3847/1538-4357/aa6b00
info:eu-repo/semantics/altIdentifier/doi/10.3847/1538-4357/aa6b00
en
cosmology: theory
cosmology: dark matter
galaxies: evolution
galaxies: groups
Galaxy: halo
methods: numerical
Astrophysics - Astrophysics of Galaxies
[SDU]Sciences of the Universe [physics]
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]
info:eu-repo/semantics/article
Journal articles
We compare the mean mass assembly histories of compact and fossil galaxy groups in the Millennium Dark Matter Simulation and an associated semi-analytic galaxy formation model. Tracing the halo mass of compact groups (CGs) from z = 0 to z = 1 shows that, on average, 55% of the halo mass in CGs is assembled since z∼ 1, compared to 40% of the halo mass in fossil groups (FGs) on the same time interval, indicating that compared to FGs, CGs are relatively younger galaxy systems. At z = 0, for a given halo mass, FGs tend to have a larger concentration than CGs. Investigating the evolution of CG’s parameters reveals that they become more compact with time. CGs at z = 0.5 see their magnitude gaps increase exponentially, but it takes ∼10 Gyr for them to reach a magnitude gap of 2 mag. The slow growth of the magnitude gap leads to only a minority (∼41%) of CGs selected at z = 0.5 turning into a FG by z = 0. Also, while three-quarters of FGs go through a compact phase, most fail to meet the CG isolation criterion, leaving only ∼30% of FGs fully satisfying the CG selection criteria. Therefore, there is no strong link of CGs turning into FGs or FGs originating from CGs. The relation between CGs and FGs is thus more complex, and in most cases, FGs and CGs follow different evolutionary tracks.
2017