Cosmic expansion from spinning black holes

Cosmic Black Holes

Production of high-energy gravitational objects is a common feature of gravitational theories. The primordial universe is a natural setting for the creation of black holes and other nonperturbative gravitational entities. Cosmic black holes can be used to probe physical properties of the very early universe which would usually require the knowledge of the theory of quantum gravity. They may be ...

Cosmic colored black holes.

We present spherically symmetric static solutions (a particle-like solution and a black hole solution) in the Einstein-Yang-Mills system with a cosmological constant. Although their gravitational structures are locally similar to those of the Bartnik-McKinnon particles or the colored black holes, the asymptotic behavior becomes quite different because of the existence of a cosmological horizon....

Cosmic Feedback from Supermassive Black Holes

Primordial black holes from cosmic necklaces

Cosmic necklaces are hybrid topological defects consisting of monopoles and strings. We argue that primordial black holes(PBH) may have formed from loops of the necklaces, if there exist stable winding states, such as coils and cycloops. Unlike the standard scenario of PBH formation from string loops, in which it has been suggested that the production ratio f becomes a tiny fraction f ∼ 10−20, ...

Mini-discs around spinning black holes

Accretion onto black holes in wind-fed binaries and in collapsars forms small rotating discs with peculiar properties. Such “mini-discs” accrete on the free-fall time without help of viscosity and nevertheless can have a high radiative efficiency. The inviscid mini-disc model was previously constructed for a non-rotating black hole. We extend the model to the case of a spinning black hole, calc...