Study of Satellite Plane Structure Characteristics Based on TNG50 Simulations: A Comparative Analysis from Plane to Nonplane Structures

Abstract In recent years, multiple plane structures of satellite galaxies have been identified in the nearby Universe, although their formation mechanisms remain unclear. In this work, we employ the TNG50-1 numerical simulation to classify satellite systems into plane and nonplane structures, based on their geometric and dynamical properties. We focus on comparing the characteristics of these plane and nonplane structures. The plane structures in TNG50-1 exhibit a mean height of 5.24 kpc, with most of them found in galaxy groups with intermediate halo virial masses within the narrow range of 10 11.5 –10 12.5 M ⊙ . Statistical analyses reveal that plane structures of satellite galaxies constitute approximately 11.30% in TNG50-1, with this proportion increasing to 27.11% in TNG100-1, aligning closely with previous observations. Additionally, central galaxies in clusters and groups hosting corotating plane structures are intermediate massive and slightly metal-poorer than those in nonplane structures. Significant differences are found between in-plane and out-of-plane satellite galaxies, suggesting that in-plane satellites exhibit slightly longer formation times and more active interstellar matter cycles. The satellites within these plane structures in TNG50-1 exhibit similar radial distributions with observations but are fainter and more massive than those in observational plane structures due to the over- or underestimation of galaxy properties in simulations. Our analysis also shows that the satellite plane structures might be affected by some low- or high-mass galaxies temporarily entering the plane structures due to the gravitational potential of the clusters and groups after the plane structures had formed.