• DOI:10.1093/mnras/stu1005
• Corpus ID: 85454047

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

@article{Pawlowski2014CoorbitingSG,
  title={Co-orbiting satellite galaxy structures are still in conflict with the distribution of primordial dwarf galaxies},
  author={Marcel S. Pawlowski and Beno{\^i}t Famaey and Helmut Jerjen and David Merritt and Pavel Kroupa and J{\"o}rg Dabringhausen and Fabian Lughausen and Duncan A. Forbes and Gerhard Hensler and Franccois Hammer and Mathieu Puech and Sylvain Fouquet and H{\'e}ctor Flores and Yanbin Yang},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2014},
  volume={442},
  pages={2362-2380}
}

• M. Pawlowski, B. Famaey, +11 authors Yanbin Yang
• Published 6 June 2014
• Physics
• Monthly Notices of the Royal Astronomical Society

Both major galaxies in the Local Group host planar distributions of co-orbiting satellite galaxies, the Vast Polar Structure (VPOS) of the Milky Way and the Great Plane of Andromeda (GPoA). The $\Lambda$CDM 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 sub-halo based $\Lambda$CDM 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 $\lesssim 10^{-3}$, and combined probability $< 10^{-5}$) if satellites are selected from a $\Lambda$CDM 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.