Co-orbiting satellite galaxy structures are still in conflict with the distribution of primordial dwarf galaxies

Marcel S. Pawlowski, Benoit Famaey, Helmut Jerjen, Gerhard Hensler, David J. Merritt, Pavel Kroupa, Joerg Dabringhausen, Fabian Lüghausen, Duncan A. Forbes, Francois Hammer, Mathieu Puech, Sylvain Fouquet, H. Flores, Yanbin Yang

Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed


Both major galaxies in the Local Group host planar distributions of co-orbiting satellite galaxies, the Vast Polar Structure (VPOS) of the MilkyWay and the Great Plane of Andromeda (GPoA). The Λ cold dark matter (ΛCDM) cosmological model did not predict these features. However, according to three recent studies the properties of the GPoA and the flattening of the VPOS are common features among subhalo based ΛCDM satellite systems, and the GPoA can be naturally explained by satellites being acquired along cold gas streams.We point out some methodological issues in these studies: either the selection of model satellites is different from that of the observed ones, or an incomplete set of observational constraints has been considered, or the observed satellite distribution is inconsistent with basic assumptions. Once these issues have been addressed, the conclusions are different: features like the VPOS and GPoA are very rare (each with probability ≲10 -3, and combined probability <10 -5) if satellites are selected from a ΛCDM simulation combined with semi-analytic modelling, and accretion along cold streams is no natural explanation of the GPoA. The origin of planar dwarf galaxy structures remains unexplained in the standard paradigm of galaxy formation.

Seiten (von - bis)2362-2380
FachzeitschriftMonthly Notices of the Royal Astronomical Society
PublikationsstatusVeröffentlicht - Aug. 2014

ÖFOS 2012

  • 103003 Astronomie
  • 103004 Astrophysik