Galaxies as simple dynamical systems: observational data disfavor dark matter and stochastic star formation

Understand

(Abridged) Galaxies are observed to be simple systems but the standard model of cosmology (SMoC) implies a haphazard merger history driven by dynamical friction on dark matter halos.

• The SMoC is tested here with the results that the dual dwarf galaxy theorem is in contradiction to the data if the SMoC is true, and the action of dynamical friction is not evident in the galaxy population.
• A consistency test for this conclusion comes from the significantly anisotropic distributions of satellite galaxies.
• Independently, the long history of failures of the SMoC have the likelihood that it describes the observed Universe to less than 10^-4 per cent.