Infall of substructures onto a Milky Way-like dark halo

Abstract

We analyse the dynamical properties of substructures in a high-resolution dark matter simulation of the formation of a Milky Way-like halo in a $\Lambda$CDM cosmology. Our goal is to shed light on the dynamical peculiarities of the Milky Way satellites. Our simulations show that about 1/3 of the subhalos have been accreted in groups. We quantify this clustering by measuring the alignment of the angular momentum of subhalos in a group. We find that this signal is visible even for objects accreted up to $z\sim 1$, i.e. 8 Gyr ago, and long after the spatial coherence of the groups has been lost due the host tidal field. This group infall may well explain the ghostly streams proposed by Lynden-Bell & Lynden-Bell to orbit the Milky Way. Our analyses also show that if most satellites originate in a few groups, the disk-like distribution of the Milky Way satellites would be almost inevitable. This non-random assignment of satellites to subhalos implies an environmental dependence on whether these low-mass objects are able to form stars, possibly related to the nature of reionization in the early Universe. With this picture, both the ``ghostly streams'' and the ``disk-like configuration'' are manifestations of the same phenomenon: the hierarchical growth of structure down to the smallest scales.

arXiv comment9 pages, 10 figures, MNRAS in press

References in corpus (49)

• Dark Matter Substructure in Galactic Halos
• Where are the missing galactic satellites?
• Populating a cluster of galaxies - I. Results at z=0
• Dwarf Galaxies of the Local Group
• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions
• The subhalo populations of LCDM dark haloes
• The tumultuous lives of galactic dwarfs and the missing satellites problem
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• A New Milky Way Dwarf Galaxy in Ursa Major
• A Faint New Milky Way Satellite in Bootes
• A New Milky Way Dwarf Satellite in Canes Venatici
• The Effects of Photoionization on Galaxy Formation - II: Satellites in the Local Group
• A New Milky Way Companion: Unusual Globular Cluster or Extreme Dwarf Satellite?
• The great disk of Milky-Way satellites and cosmological sub-structures
• Internal and External Alignment of the Shapes and Angular Momenta of LCDM Halos
• A Curious New Milky Way Satellite in Ursa Major
• Substructures in Cold Dark Matter Haloes
• The Structure and Dynamical Evolution of Dark Matter Halos
• Discovery of an Unusual Dwarf Galaxy in the Outskirts of the Milky Way
• The Anisotropic Distribution of Galactic Satellites
• The Milky Way's satellite population in a LambdaCDM universe
• The radial velocity dispersion profile of the Galactic halo: Constraining the density profile of the dark halo of the Milky Way
• Is the SMC Bound to the LMC? The HST Proper Motion of the SMC
• The Distribution of Satellite Galaxies: The Great Pancake
• A new view of the dwarf spheroidal satellites of the Milky Way from VLT/FLAMES: Where are the very metal poor stars?
• Dark matter annihilation in the halo of the Milky Way
• The spatial distribution of the Milky Way and Andromeda satellite galaxies
• Galaxies and subhaloes in LCDM galaxy clusters
• Deciphering The Last Major Invasion of the Milky Way Galaxy
• Infall of substructures onto a Milky Way-like dark halo
• Formation and evolution of the Magellanic Clouds. I.Origin of structural, kinematical, and chemical properties of the Large Magellanic Cloud
• Cosmic Ménage à Trois: The Origin of Satellite Galaxies On Extreme Orbits
• Simulating IGM Reionization
• Anisotropy in the Distribution of Satellite Galaxy Orbits
• The Anisotropic Distribution of M 31 Satellite Galaxies: A Polar Great Plane of Early-Type Companions
• The satellite distribution of M31
• Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. IV: Measurement for Sculptor
• Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. V: Final Measurement for Fornax
• Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. III: Measurement for Ursa Minor
• On the Distribution of Orbital Poles of Milky Way Satellites
• Satellite Systems around Galaxies in Hydrodynamic Simulations
• Are Great Disks Defined by Satellite Galaxies in Milky-Way Type Halos Rare in $\Lambda$CDM model?
• Absolute Proper Motion of the Fornax Dwarf Spheroidal Galaxy from Photographic and HST WFPC2 Data
• Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. I: Method and a Preliminary Measurement for Fornax
• High-Redshift Galaxy Outflows and the Formation of Dwarf Galaxies
• Circular velocity profiles of dark matter haloes
• Dependence of the Local Reionization History on Halo Mass and Environment: Did Virgo Reionize the Local Group?
• Impact of UV Radiation from Giant Spirals on the Evolution of Dwarf Galaxies

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