Volume 490, Number 3, November II 2008
|Page(s)||965 - 973|
|Published online||17 September 2008|
Fossil groups in the Millennium Simulation
Evolution of the brightest galaxies
IATE (CONICET-UNC) & OAC (UNC), Laprida 854, Córdoba 5000, Argentina e-mail: email@example.com; firstname.lastname@example.org
2 IAG, USP. Rua do Matão 1226, São Paulo, Brazil e-mail: email@example.com
Accepted: 19 August 2008
Aims. We create a catalogue of simulated fossil groups and study their properties, in particular the merging histories of their first-ranked galaxies. We compare the simulated fossil group properties with those of both simulated non-fossil and observed fossil groups.
Methods. Using simulations and a mock galaxy catalogue, we searched for massive (>5 10) fossil groups in the Millennium Simulation Galaxy Catalogue. In addition, we attempted to identify observed fossil groups in the Sloan Digital Sky Survey Data Release 6 using identical selection criteria.
Results. Our predictions on the basis of the simulation data are: (a) fossil groups comprise about 5.5% of the total population of groups/clusters with masses larger than 5 10. This fraction is consistent with the fraction of fossil groups identified in the SDSS, after all observational biases have been taken into account; (b) about 88% of the dominant central objects in fossil groups are elliptical galaxies that have a median R-band absolute magnitude of ~, which is typical of the observed fossil groups known in the literature; (c) first-ranked galaxies of systems with 5 10, regardless of whether they are either fossil or non-fossil, are mainly formed by gas-poor mergers; (d) although fossil groups, in general, assembled most of their virial masses at higher redshifts in comparison with non-fossil groups, first-ranked galaxies in fossil groups merged later, i.e. at lower redshifts, compared with their non-fossil-group counterparts.
Conclusions. We therefore expect to observe a number of luminous galaxies in the centres of fossil groups that show signs of a recent major merger.
Key words: methods: N-body simulations / methods: statistical / galaxies: clusters: general / galaxies: evolution
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.