- It is well known that satellite galaxies are not isotropically distributed among their host galaxies as suggested by most interpretations of the Λ cold dark matter (ΛCDM) model. One type of anisotropy recently detected in the Sloan Digital Sky Survey (and seen when examining the distribution of satellites in the Local Group and in the Centaurus group) is a tendency to be so-called lopsided. Namely, in pairs of galaxies (like Andromeda and the Milky Way) the satellites are more likely to inhabit the region in between the pair, rather than on opposing sides. Although recent studies found a similar set-up when comparing pairs of galaxies in ΛCDM simulations indicating that such a set-up is not inconsistent with ΛCDM, the origin has yet to be explained. Here we examine the origin of such lopsided set-ups by first identifying such distributions in pairs of galaxies in numerical cosmological simulations, and then tracking back the orbital trajectories of satellites (which at z = 0 display the effect). We report two main results: first, theIt is well known that satellite galaxies are not isotropically distributed among their host galaxies as suggested by most interpretations of the Λ cold dark matter (ΛCDM) model. One type of anisotropy recently detected in the Sloan Digital Sky Survey (and seen when examining the distribution of satellites in the Local Group and in the Centaurus group) is a tendency to be so-called lopsided. Namely, in pairs of galaxies (like Andromeda and the Milky Way) the satellites are more likely to inhabit the region in between the pair, rather than on opposing sides. Although recent studies found a similar set-up when comparing pairs of galaxies in ΛCDM simulations indicating that such a set-up is not inconsistent with ΛCDM, the origin has yet to be explained. Here we examine the origin of such lopsided set-ups by first identifying such distributions in pairs of galaxies in numerical cosmological simulations, and then tracking back the orbital trajectories of satellites (which at z = 0 display the effect). We report two main results: first, the lopsided distribution was stronger in the past and weakens towards z = 0. Secondly, the weakening of the signal is due to the interaction of satellite galaxies with the pair. Finally, we show that the z = 0 signal is driven primarily by satellites that are on first approach, who have yet to experience a ‘flyby’. This suggests that the signal seen in the observations is also dominated by dynamically young accretion events.…
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MetadatenAuthor details: | Chen Chris GongORCiD, Noam I. LibeskindORCiD, Elmo TempelORCiDGND, Quan Guo, Stefan Gottloeber, Gustavo YepesORCiD, Peng Wang, Jenny SorceGND, Marcel PawlowskiORCiDGND |
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DOI: | https://doi.org/10.1093/mnras/stz1917 |
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ISSN: | 0035-8711 |
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ISSN: | 1365-2966 |
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Title of parent work (English): | Monthly notices of the Royal Astronomical Society |
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Publisher: | Oxford Univ. Press |
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Place of publishing: | Oxford |
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Publication type: | Article |
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Language: | English |
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Date of first publication: | 2019/07/11 |
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Publication year: | 2019 |
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Release date: | 2020/11/16 |
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Tag: | Local Group; cosmology: theory; dark matter; galaxies: evolution; galaxies: formation; galaxy: kinematics and dynamics |
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Volume: | 488 |
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Issue: | 3 |
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Number of pages: | 9 |
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First page: | 3100 |
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Last Page: | 3108 |
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Funding institution: | Project IDEXLYON at theUniversity of Lyon under the Investments for the Future Program [ANR-16-IDEX-0005]; joint Sino-German DFG research the ERDF CoE [TK133, MOBTP86]; Ministerio de Economia y CompetitividadSpanish Government; Fondo Europeo de Desarrollo Regional (MINECO/FEDER, UE) in Spain [AYA2015-63810-P, PGC2018-094975-B-C21]; programme; Spanish MultiDark Consolider Project [CSD2009-00064] |
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Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
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DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
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Peer review: | Referiert |
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Publishing method: | Open Access |
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| Open Access / Green Open-Access |
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