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Title: Is There a Disk of Satellites around the Milky Way?

Abstract

The “disk of satellites” (DoS) around the Milky Way is a highly debated topic with conflicting interpretations of observations and their theoretical models. We perform a comprehensive analysis of all of the dwarfs detected in the Milky Way and find that the DoS structure depends strongly on the plane identification method and the sample size. In particular, we demonstrate that a small sample size can artificially produce a highly anisotropic spatial distribution and a strong clustering of the angular momentum of the satellites. Moreover, we calculate the evolution of the 11 classical satellites with proper motion measurements and find that the thin DoS in which they currently reside is transient. Furthermore, we analyze two cosmological simulations using the same initial conditions of a Milky-Way-sized galaxy, an N -body run with dark matter only, and a hydrodynamic one with both baryonic and dark matter, and find that the hydrodynamic simulation produces a more anisotropic distribution of satellites than the N -body one. Our results suggest that an anisotropic distribution of satellites in galaxies can originate from baryonic processes in the hierarchical structure formation model, but the claimed highly flattened, coherently rotating DoS of the Milky Way may be biased by themore » small-number selection effect. These findings may help resolve the contradictory claims of DoS in galaxies and the discrepancy among numerical simulations.« less

Authors:
; ;  [1];  [2]
  1. Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)
  2. Department of Physics, Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
Publication Date:
OSTI Identifier:
22663434
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 843; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR MOMENTUM; ANISOTROPY; BARYONS; COMPUTERIZED SIMULATION; GALACTIC EVOLUTION; HYDRODYNAMICS; MILKY WAY; NONLUMINOUS MATTER; PROPER MOTION; SATELLITES; SPATIAL DISTRIBUTION

Citation Formats

Maji, Moupiya, Zhu, Qirong, Li, Yuexing, and Marinacci, Federico, E-mail: moupiya@psu.edu. Is There a Disk of Satellites around the Milky Way?. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA72F5.
Maji, Moupiya, Zhu, Qirong, Li, Yuexing, & Marinacci, Federico, E-mail: moupiya@psu.edu. Is There a Disk of Satellites around the Milky Way?. United States. doi:10.3847/1538-4357/AA72F5.
Maji, Moupiya, Zhu, Qirong, Li, Yuexing, and Marinacci, Federico, E-mail: moupiya@psu.edu. Sat . "Is There a Disk of Satellites around the Milky Way?". United States. doi:10.3847/1538-4357/AA72F5.
@article{osti_22663434,
title = {Is There a Disk of Satellites around the Milky Way?},
author = {Maji, Moupiya and Zhu, Qirong and Li, Yuexing and Marinacci, Federico, E-mail: moupiya@psu.edu},
abstractNote = {The “disk of satellites” (DoS) around the Milky Way is a highly debated topic with conflicting interpretations of observations and their theoretical models. We perform a comprehensive analysis of all of the dwarfs detected in the Milky Way and find that the DoS structure depends strongly on the plane identification method and the sample size. In particular, we demonstrate that a small sample size can artificially produce a highly anisotropic spatial distribution and a strong clustering of the angular momentum of the satellites. Moreover, we calculate the evolution of the 11 classical satellites with proper motion measurements and find that the thin DoS in which they currently reside is transient. Furthermore, we analyze two cosmological simulations using the same initial conditions of a Milky-Way-sized galaxy, an N -body run with dark matter only, and a hydrodynamic one with both baryonic and dark matter, and find that the hydrodynamic simulation produces a more anisotropic distribution of satellites than the N -body one. Our results suggest that an anisotropic distribution of satellites in galaxies can originate from baryonic processes in the hierarchical structure formation model, but the claimed highly flattened, coherently rotating DoS of the Milky Way may be biased by the small-number selection effect. These findings may help resolve the contradictory claims of DoS in galaxies and the discrepancy among numerical simulations.},
doi = {10.3847/1538-4357/AA72F5},
journal = {Astrophysical Journal},
number = 1,
volume = 843,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}