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The fossil phase in the life of a galaxy group

Von Benda-Beckmann, Alexander M. ; D'Onghia, Elena ; Gottlöber, Stefan ; Hoeft, Matthias ; Khalatyan, Arman ; Klypin, Anatoly ; Müller, Volker

In: Monthly Notices of the Royal Astronomical Society, 2008, vol. 386, no. 4, p. 2345-2352

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    Titre
    • The fossil phase in the life of a galaxy group
    Auteur
    • Von Benda-Beckmann, Alexander M.. Astrophysical Institute Potsdam, An der Sternwarte 16, Germany
    • D'Onghia, Elena. Institute for Theoretical Physics, University of Zurich, Winterthurerstrasse 190, Switzerland
    • Gottlöber, Stefan. Astrophysical Institute Potsdam, An der Sternwarte 16, Germany
    • Hoeft, Matthias. Jacobs University Bremen, Campus Ring 12, Germany
    • Khalatyan, Arman. Astrophysical Institute Potsdam, An der Sternwarte 16, Germany
    • Klypin, Anatoly. Astronomy Department, New Mexico State University, MSC 4500, PO Box 30001, Las Cruces, NM 880003-8001, USA
    • Müller, Volker. Astrophysical Institute Potsdam, An der Sternwarte 16, Germany
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2008, vol. 386, no. 4, p. 2345-2352. Blackwell Publishing Ltd
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:293377
    Summary
    We investigate the origin and evolution of fossil groups in a concordance ΛCDM cosmological simulation. We consider haloes with masses between 1 × 1013 and 5 × 1013h−1M⊙, and study the physical mechanisms that lead to the formation of the large gap in magnitude between the brightest and the second most bright group member, which is typical for these fossil systems. Fossil groups are found to have high dark matter concentrations, which we can relate to their early formation time. The large magnitude gaps arise after the groups have built up half of their final mass, due to merging of massive group members. We show that the existence of fossil systems is primarily driven by the relatively early infall of massive satellites, and that we do not find a strong environmental dependence for these systems. In addition, we find tentative evidence for fossil group satellites falling in on orbits with typically lower angular momentum, which might lead to a more efficient merger on to the host. We find a population of groups at higher redshifts that go through a ‘fossil phase': a stage where they show a large magnitude gap, which is terminated by renewed infall from their environment