Dark Ages – University of Copenhagen

Research at Dark Cosmology Centre in Dark Ages

The dark ages represent the period between the release of the cosmic microwave background radiation about 300,000 years after the Big Bang and the formation of the first shining objects, a few hundred million years after the Big Bang.

This period was dark in the sense that there were no sources of light in the Universe. Yet, it is crucial for our understanding of cosmology as this was when the first structures formed through gravitational instability, in particular the first stars, galaxies and super-massive black holes.

Some of the most important theoretical issues in this field include:

  • The formation of the first dark matter haloes in which the first shining objects presumably are located. The epoch and nature of this is critically dependent on the mass of the dark matter particles.
  • The nature of the first stars, in particular the shape of the initial mass function, which describes the mass spectrum of stars formed.
  • How did supermassive black holes form? There is evidence that supermassive black holes with masses of the order of 109 solar masses were present already 1 billion years after the Big Bang (we see them as bright quasars), and it is difficult to understand how they can have formed so rapidly.
  • How did the Universe re-ionize, and which sources dominated the formation of the ultraviolet photons responsible for re-ionization. The best candidates are the first stars, but quasars and perhaps decaying dark matter particles may play a role.