Spatial and orbital planes of the Milky Way satellites: unusual but consistent with $\Lambda$CDM

Abstract

We examine the spatial distribution and orbital pole correlations of satellites in a suite of zoom-in high-resolution dissipationless simulations of Miky Way (MW) sized haloes. We use the measured distribution to estimate the incidence of satellite configurations as flattened and as correlated in their orbital pole distribution as satellite system of the Milky Way. We confirm that this incidence is sensitive to the radial distribution of subhaloes and thereby to the processes that affect it, such as artificial disruption due to numerical effects and disruption due to the central disk. Controlling for the resolution effects and bracketing the effects of the disk, we find that the MW satellite system is somewhat unusual (at the $\approx 2-3\sigma$ level) but is statistically consistent with the $\Lambda$CDM model, in general agreement with results and conclusions of other recent studies.

10 pages, 7 figures, submitted to MNRAS

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• Detection and characterization of detached tidal dwarf galaxies
• A Study of the Properties and Dynamics of the Disk of Satellites in a Milky-Way-like Galaxy System
• Densities and mass assembly histories of the Milky Way satellites are not a challenge to $\Lambda$CDM