A Rotating Satellite Plane around Milky Way–like Galaxy from the TNG50 Simulation

Abstract

We study the satellite plane problem of the Milky Way (MW) by using the recently published simulation data of TNG50-1. Here, we only consider the satellite plane consisting of the brightest 14 MW satellites (11 classical satellites plus Canes Venatici I, Crater II, and Antlia II). One halo (haloID = 395, at z = 0, hereafter halo395) of 231 MW-like candidates possesses a satellite plane as spatially thin and kinematically coherent as the observed one has been found. Halo395 resembles the MW in a number of intriguing ways: it hosts a spiral central galaxy, and its satellite plane is almost (∼87°) perpendicular to the central stellar disk. In addition, halo395 is embedded in a sheet plane, with a void on the top and bottom, similar to the local environment of MW. More interestingly, we found that 11 of the 14 of the satellites on the plane of halo395 arise precisely from the peculiar geometry of its large-scale environment (e.g., sheet and voids). The remaining three members appeared at the right place with the right velocity by chance at z = 0. Our results support previous studies wherein the satellite plane problem is not seen as a serious challenge to the ΛCDM model and its formation is ascribed to the peculiarities of our environment.