Planes of satellite galaxies: when exceptions are the rule

Abstract

The detection of planar structures within the satellite systems of both the Milky Way (MW) and Andromeda (M31) has been reported as being in stark contradiction to the predictions of the standard cosmological model ($\Lambda$CDM). Given the ambiguity in defining a planar configuration, it is unclear how to interpret the low incidence of the MW and M31 planes in $\Lambda$CDM. We investigate the prevalence of satellite planes around galactic mass haloes identified in high resolution cosmological simulations. We find that planar structures are very common, and that ~10% of $\Lambda$CDM haloes have even more prominent planes than those present in the Local Group. While ubiquitous, the planes of satellite galaxies show a large diversity in their properties. This precludes using one or two systems as small scale probes of cosmology, since a large sample of satellite systems is needed to obtain a good measure of the object-to-object variation. This very diversity has been misinterpreted as a discrepancy between the satellite planes observed in the Local Group and $\Lambda$CDM predictions. In fact, ~10% of $\Lambda$CDM galactic haloes have planes of satellites that are as infrequent as the MW and M31 planes. The look-elsewhere effect plays an important role in assessing the detection significance of satellite planes and accounting for it leads to overestimating the significance level by a factor of 30 and 100 for the MW and M31 systems, respectively.

13 pages, 15 figures, +3 pages appendix, MNRAS accepted version

References in corpus (22)

• A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
• Co-orbiting satellite galaxy structures are still in conflict with the distribution of primordial dwarf galaxies
• The orbital poles of Milky Way satellite galaxies: a rotationally supported disc-of-satellites
• Two Planes of Satellites in the Centaurus A Group
• Satellite abundances around bright isolated galaxies
• Planes of satellite galaxies and the cosmic web
• Estimating the dark matter halo mass of our Milky Way using dynamical tracers
• Velocity anti-correlation of diametrically opposed galaxy satellites in the low redshift universe
• A thousand shadows of Andromeda: rotating planes of satellites in the Millennium-II cosmological simulation
• The Copernicus Complexio: a high-resolution view of the small-scale Universe
• The outer halo globular cluster system of M31 - II. Kinematics
• Discs of Satellites: the new dwarf spheroidals
• The universal nature of subhalo accretion
• Milky Way mass constraints from the Galactic satellite gap
• Vast planes of satellites in a high resolution simulation of the Local Group: comparison to Andromeda
• A new spin on disks of satellite galaxies
• Are rotating planes of satellite galaxies ubiquitous?
• Subhalo statistics of galactic halos: beyond the resolution limit
• Eppur si muove: Positional and kinematic correlations of satellite pairs in the low Z universe
• The Milky Way system in LCDM cosmological simulations
• Proper Motion of the Draco Dwarf Galaxy Based On Hubble Space Telescope Imaging
• Local Group galaxies emerge from the dark

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• The large-scale structure of the halo of the Andromeda galaxy II. Hierarchical structure in the Pan-Andromeda Archaeological Survey
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• NIHAO XV: The environmental impact of the host galaxy on galactic satellite and field dwarf galaxies
• The Planes of Satellite Galaxies Problem, Suggested Solutions, and Open Questions
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• The M101 group complex: new dwarf galaxy candidates and spatial structure
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• The Role of Baryons in Creating Statistically Significant Planes of Satellites around Milky Way-Mass Galaxies
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• A Plane of High Velocity Galaxies Across the Local Group
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• A Formation Scenario for the Disk of Satellites: Accretion of Satellites during Mergers
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• The orientation of planes of dwarf galaxies in the quasi-linear Universe
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• The Missing Satellite Problem Outside of the Local Group: I -- Pilot Observation
• Considerations on how to investigate planes of satellite galaxies
• The stellar mass in and around isolated central galaxies: connections to the total mass distribution through galaxy-galaxy lensing in the Hyper Suprime-Cam survey
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• We are not the 99 percent: quantifying asphericity in the distribution of Local Group satellites
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• Planes of satellites around simulated disk galaxies II: Time-persistent planes of kinematically-coherent satellites in $\Lambda$CDM
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• Self-Calibrating the Look-Elsewhere Effect: Fast Evaluation of the Statistical Significance Using Peak Heights
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