The Orbital Poles of Milky Way Satellite Galaxies: A Rotationally Supported Disk of Satellites

By M. Metz, Pavel Kroupa, N. Libeskind. 2008

135 citations recorded by the source corpus.

We use available proper-motion measurements of Milky Way (MW) satellite galaxies to calculate their orbital poles and projected uncertainties. These are compared with a set of recent cold dark matter (CDM) simulations tailored specifically to solve the MW satellite problem. We show that the CDM satellite orbital poles are fully consistent with being drawn from a random distribution, while the MW satellite orbital poles indicate that the “disk of satellites” of the Milky Way is rotationally supported. Furthermore, a bootstrap analysis of the spatial distribution of theoretical CDM satellites also shows that they are consistent with being randomly drawn. The theoretical CDM satellite population thus shows a significantly different orbital and spatial distribution from that of the MW satellites, most probably indicating that the majority of the latter are of tidal origin rather than being dark matter-dominated substructures. A statistic is presented that can be used to test a possible correlation of satellite galaxy orbits with their spatial distribution.

Subfields: Astronomy and Astrophysics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/35bc4c4c7ebdc978d2e3739858a283bda59207c0

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Statistical and Nonlinear Physics

Citations in the corpus

CONFIRMATION OF FAINT DWARF GALAXIES IN THE M81 GROUP (2013, background): “Meanwhile most of the early type companions to the Milky Way appear to lie in a plane (Lynden-Bell 1976; Metz et al. 2008; Pawlowski et al. 2012).”
Small scale problems of the $\Lambda$CDM model: a short review (2016, background): “e Plane Problem From the seventies on, it was noticed by several authors that the MW satellites are distributed on a planar structure, the so-called “Magellanic Plane” [78,79], the disc of satellites [46,80], the MW “Vast popular structure” (VPOS) , and the “great plane of andromeda” (GPoA) [44,72,8”
Dwarf galaxy planes: the discovery of symmetric structures in the Local Group (2013, background): “To account for the coherent orbital directions of MW satellites within the VPOS (Metz et al. 2008; Pawlowski & Kroupa 2013), it has been suggested that some of them might have been accreted onto the MW together as a group (Li & Helmi 2008; D’Onghia & Lake 2008; Deason et al. 2011).”
Co-orbiting satellite galaxy structures are still in conflict with the distribution of primordial dwarf galaxies (2014, methodology): “…1 The feature which we call the VPOS is called the ’Magellanic plane’ by Kunkel & Demers (1976) and Lynden-Bell (1976); the ’great pancake’ by Libeskind et al. (2005), Li & Helmi (2008) and Wang et al. (2013); and the disc of satellites by Kroupa et al. (2005) and Metz et al. (2008).”
Galaxies as simple dynamical systems: observational data disfavor dark matter and stochastic star formation (2014, background): “The highly significant existence of the very large (≈ 500 kpc in diameter) planar or disk-like (thickness ≈ 50 kpc) distribution of material around the MW [8, 85], which we know to be mostly rotating in one sense [172, 173], can most naturally, and probably only, be explained as the MW satellite gal”
THE INVISIBLES: A DETECTION ALGORITHM TO TRACE THE FAINTEST MILKY WAY SATELLITES (2008, background): “Metz et al. (2008) refute this conclusion, finding instead that the orbital poles of most MW satellites place them in a rotationally supported disk-of-satellites.”
The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology (2012, background): “The Disk of Satellites (DoS/VPOS, 2005) The observed satellite galaxies of the MW are arranged in a vast polar structure (Kroupa, Theis & Boily 2005; Metz et al. 2007, 2008, 2009a; Kroupa et al. 2010; Pawlowski et al. 2012b).”
The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way (2012, background): “It has already been pointed out that the Sagittarius satellite galaxy is not orbiting within the DoS (Metz et al. 2008), the stream-normal is at an angular distance of 64◦ from the DoS normal.”
Local-Group tests of dark-matter concordance cosmology - Towards a new paradigm for structure formation (2010, background): “Both, the normal and the average orbital angular momentum vector are nearly co-aligned implying a strong degree ofphase-space correlationbetween the satellites such that the DoS is rotating (Metz et al. 2008).”