Properties of galaxies reproduced by a hydrodynamic simulation

Abstract

Previous simulations of the growth of cosmic structures have broadly reproduced the â ̃ cosmic web' of galaxies that we see in the Universe, but failed to create a mixed population of elliptical and spiral galaxies, because of numerical inaccuracies and incomplete physical models. Moreover, they were unable to track the small-scale evolution of gas and stars to the present epoch within a representative portion of the Universe. Here we report a simulation that starts 12 million years after the Big Bang, and traces 13 billion years of cosmic evolution with 12 billion resolution elements in a cube of 106.5â ‰megaparsecs a side. It yields a reasonable population of ellipticals and spirals, reproduces the observed distribution of galaxies in clusters and characteristics of hydrogen on large scales, and at the same time matches the ' metal' and hydrogen content of galaxies on small scales. © 2014 Macmillan Publishers Limited.