PUBLICATIONS OF THE ASTRONOMICAL OBSERVATORY OF BELGRADE104, Page 59-65, https://doi.org/10.69646/aob104p059
PROCEEDINGS of the XX Serbian Astronomical Conference, Belgrade, October 16 - 20, 2023, Edited by Jelena Petrović, Dušan Marčeta and Ana Lalović
Published by: Astronomical Observatory, Volgina 7, 11060 Belgrade 38, Serbia

Abstract. Driven by the increasingly complete observational knowledge of systems of satel- lite galaxies, mutual spatial alignments and relations in velocities among satellites belonging to a common host have become a productive field of research. The Planes of Satellite Galax- ies issue is maybe the best-known type of such phase-space correlations, with an ongoing, controversial debate on how much of a challenge it poses for the ΛCDM model of cosmol- ogy. With the fast expansion of proper motion measurements in recent years, largely driven by the Gaia mission, other peculiar phase-space correlations have been uncovered among the satellites of the Milky Way. At the same time, more complete observational samples of satellite galaxies around more distant hosts now enable us to expand the study of such cor- relations to the Andromeda galaxy and beyond. This contribution briefly reviews the highly active field of phase-space correlations among satellite galaxy systems, mainly summarizing recent results concerning observed satellite structures and what formation scenarios have been suggested for these peculiar arrangements.