Unveiling the Structure of Milky Way Satellite Planes: Exploring Planarity in a Cosmic Context

The study introduces "planarity" to assess the alignment of Milky Way satellite galaxies, finding significant positional but inconclusive kinematic coherence due to velocity data errors. Simulations reveal that such planarity is common and kinematically supported in MW-like galaxies, aligning with the ΛCDM model. This suggests satellite planes are shaped by cosmic web structures and are consistent with hierarchical galaxy formation theories.