2022/08/10 by P U Förster, Förster, Pascal U., Rhea–Silvia Remus +9
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2208.05496
openalex publication_date 2022/08/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Planes of satellites are observed around many galaxies. However, these observations are still considered a point of tension for the ΛCDM paradigm. We use the fully hydrodynamical cosmological ΛCDM state-of-the-art simulation Magneticum Pathfinder to investigate the existence of such planes over a large range of haloes, from Milky Way to galaxy cluster masses. To this end, we develop the Momentum in Thinnest Plane (MTP) method to identify planes and quantify the properties of their constituent satellites, considering both position and momentum. We find that thin planes (20%⋅ Rhalo) containing at least 50% of the total number of satellites can be found in almost all systems. In Milky Way mass-like systems, around 86% of such planes are even aligned in momentum (90% of the total satellite momentum), where the fraction is smaller if more satellites are required to be inside the plane. We further find a mass dependency, with more massive systems exhibiting systematically thicker planes. This may point towards the change from continuous accretion of small objects along filaments and sheets for less massive haloes to the accretion of large objects (e.g., major mergers) dominating the growth of more massive haloes. There is no correlation between the existence of a plane and the main galaxy's morphology. Finally, we find a clear preference for the minor axes of the satellite planes and the host galaxy to be aligned, in agreement with recent observations.