Are disks of satellites comprised of tidal dwarf galaxies?

Abstract

It was found that satellites of nearby galaxies can form flattened co-rotating structures called disks of satellites or planes of satellites. Their existence is not expected by the current galaxy formation simulations in the standard dark-matter-based cosmology. On the contrary, modified gravity offers a promising alternative: the objects in the disks of satellites are tidal dwarf galaxies, that is small galaxies that form from tidal tails of interacting galaxies. After introducing the topic, we review here our work on simulating the formation of the disks of satellites of the Milky Way and Andromeda galaxies. The initial conditions of the simulation were tuned to reproduce the observed positions, velocities and disk orientations of the galaxies. The simulation showed that the galaxies had a close flyby 6.8Gyr ago. One of the tidal tails produced by the Milky Way was captured by Andromeda. It formed a cloud of particles resembling the disk of satellites at Andromeda by its size, orientation, rotation and mass. A hint of a disk of satellites was formed at the Milky Way too. In addition, the encounter induced a warp in the disk of the simulated Milky Way that resembles the real warp by its magnitude and orientation. We present here, for the first time, the proper motions of the members of the disk of satellites of Andromeda predicted by our simulation. Finally, we point out some of the remaining open questions which this hypothesis for the formation of disks of satellites brings up.

arXiv comment16 pages, 4 figures. Accepted as an invited contribution to the special issue "Challenges in Our Understanding of Dwarf Galaxies" of the Galaxies journal. Shortened and updated version of the paper Bilek et al., A&A, 614, A59, 2018

References in corpus (63)

• Where are the missing galactic satellites?
• Co-formation of the Galactic disc and the stellar halo
• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• Evidence for Two Early Accretion Events That Built the Milky Way Stellar Halo
• A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
• The Atlas3D project -- XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images
• The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way
• The M31 Velocity Vector. II. Radial Orbit Towards the Milky Way and Implied Local Group Mass
• A new relativistic theory for Modified Newtonian Dynamics
• The published extended rotation curves of spiral galaxies: Confrontation with Modified Dynamics
• Quenching and ram pressure stripping of simulated Milky Way satellite galaxies
• Clumpy Galaxies in GOODS and GEMS: Massive Analogs of Local Dwarf Irregulars
• Galaxies as simple dynamical systems: observational data disfavor dark matter and stochastic star formation
• A whirling plane of satellite galaxies around Centaurus A challenges cold dark matter cosmology
• Confirmation of Faint Dwarf Galaxies in the M81 Group
• Dwarf Galaxy Planes: the discovery of symmetric structures in the Local Group
• MOND and the "Dearth of Dark Matter in Ordinary Elliptical Galaxies"
• The rotationally stabilized VPOS and predicted proper motions of the Milky Way satellite galaxies
• The orbital poles of Milky Way satellite galaxies: a rotationally supported disc-of-satellites
• Infall of substructures onto a Milky Way-like dark halo
• Testing Modified Newtonian Dynamics with Low Surface Brightness Galaxies --Rotation curve fits-
• Two Planes of Satellites in the Centaurus A Group
• Surface Brightness Profiles and Structural Parameters for Globular Clusters in the Fornax and Sagittarius Dwarf Spheroidal Galaxies
• The Shapes and Alignments of Dark Matter Halos
• Local Group Dwarf Spheroidals: Correlated Deviations from the Baryonic Tully-Fisher Relation
• Crater 2: An Extremely Cold Dark Matter Halo
• The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia DR2
• The KBC void and Hubble tension contradict $\Lambda$CDM on a Gpc scale $-$ Milgromian dynamics as a possible solution
• Velocity anti-correlation of diametrically opposed galaxy satellites in the low redshift universe
• Andromeda Dwarfs in Light of MOND. II. Testing Prior Predictions
• Did the Milky Way dwarf satellites enter the halo as a group?
• Declining rotation curves of galaxies as a test of gravitational theory
• A massive blow for $\Lambda$CDM $-$ the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology
• Census and classification of low-surface-brightness structures in nearby early-type galaxies from the MATLAS survey
• The survival of the Sgr dwarf galaxy and the flatness of the rotation curve of the Galaxy
• Dynamical friction in modified Newtonian dynamics
• On the stellar masses of giant clumps in distant star-forming galaxies
• Dwarf elliptical galaxies as ancient tidal dwarf galaxies
• A general class of gravitational theories as alternatives to dark matter where the speed of gravity always equals the speed of light
• Star formation triggered by galaxy interactions in modified gravity
• Testing MOND Over a Wide Acceleration Range in X-Ray Ellipticals
• The abundance of galaxy clusters in MOND: Cosmological simulations with massive neutrinos
• Comparing the observable properties of dwarf galaxies on and off the Andromeda plane
• RAyMOND: An N-body and hydrodynamics code for MOND
• Theia: Faint objects in motion or the new astrometry frontier
• Newly discovered dwarf galaxies in the MATLAS low density fields
• MOND rotation curves of very low mass spiral galaxies
• MOND in galaxy groups: a superior sample
• The alignment of SDSS satellites with the VPOS: effects of the survey footprint shape
• A Plane of High Velocity Galaxies Across the Local Group
• The proper motion of Andromeda from Gaia eDR3: confirming a nearly radial orbit
• Understanding the internal dynamics of elliptical galaxies without non-baryonic dark matter
• The mass-metallicity relation of tidal dwarf galaxies
• Local Group galaxies emerge from the dark
• The velocity field in MOND cosmology
• Long Tidal Tails in Merging Galaxies and Their Implications
• Dynamical History of the Local Group in $\Lambda$CDM
• Spiral arms and disc stability in the Andromeda galaxy
• MOND in galaxy groups
• MOND and the Galaxies
• On the absence of backsplash analogues to NGC 3109 in the $\Lambda$CDM framework
• Simulating disk galaxies and interactions in Milgromian dynamics
• Evolution of globular-cluster systems of ultra-diffuse galaxies due to dynamical friction in MOND gravity