Vast planes of satellites in a high-resolution simulation of the local group: Comparison to andromeda

The Astrophysical Journal 800.1 (2015): 34 reproduced by permission of the AASWe search for vast planes of satellites (VPoS) in a high-resolution simulation of the Local Group performed by the CLUES project, which improves significantly the resolution of previous similar studies. We use a simple method for detecting planar configurations of satellites, and validate it on the known plane of M31. We implement a range of prescriptions for modeling the satellite populations, roughly reproducing the variety of recipes used in the literature, and investigate the occurrence and properties of planar structures in these populations. The structure of the simulated satellite systems is strongly non-random and contains planes of satellites, predominantly co-rotating, with, in some cases, sizes comparable to the plane observed in M31 by Ibata et al. However, the latter is slightly richer in satellites, slightly thinner, and has stronger co-rotation, which makes it stand out as overall more exceptional than the simulated planes, when compared to a random population. Although the simulated planes we find are generally dominated by one real structure forming its backbone, they are also partly fortuitous and are thus not kinematically coherent structures as a whole. Provided that the simulated and observed planes of satellites are indeed of the same nature, our results suggest that the VPoS of M31 is not a coherent disk and that one-third to one-half of its satellites must have large proper motions perpendicular to the planeThis study was performed in the context of the EMMA (ANR-12-JS05-0001) and LIDAU project (ANR-09-BLAN-0030), funded by the Agence Nationale de la Recherche (ANR). The RT computations were performed using HPC resources from GENCI-[CINES/IDRIS] (grant 2011-[x2011046667]), on the hybrid queue of titane at Centre de Calcul Recherche et Technologie, as well as Curie, during a grand challenge time allocation (project PICON: Photo-Ionisation of CONstrained realizations of the local group). The CLUES simulations were performed at the Leibniz Rechenzentrum Munich (LRZ) and at the Barcelona Supercomputing Center (BSC). A.K. is supported by the Ministerio de Economía y Competitividad (MINECO) in Spain through grant AYA2012-31101 as well as the ConsoliderIngenio 2010 Programme of the Spanish Ministerio de Ciencia e Innovación (MICINN) under grant MultiDark CSD2009-00064. He also acknowledges support from the Australian Research Council (ARC) grants DP130100117 and DP140100198. He further thanks Stella for l’idole des jaunes. The authors thank C. Scannapieco for precious hints dispensed in the initial phase of the project, as well as the CLUES collaborators for useful discussions. The authors thank D. Munro for freely distributing his Yorick programming language, and its yorick-gl extension which was used in the course of this stud