IXO Science

The properties and evolution of accreting black holes


IXO has the capability to study astrophysical black holes on all scales, from the event horizon to the largest radio lobes, and from stellar mass black holes in Galactic binaries out to the most distant parts of the observable Universe. The major science topics to be addressed by IXO are


The Growth of Supermassive Black Holes Across Cosmic Time

  • When did the first supermassive black holes form?
  • How did the accretion power in the Universe subsequently evolve?
  • How did feedback from supermassive black holes shape the properties of galaxies?
  • Matter in extreme environments

  • How does matter behave close to the event horizon of a black hole?
  • Does it obey the predictions of general relativity?
  • Are black holes in the centers of galaxies spinning, and does that spin evolve with cosmic time?

    The energetics and dynamics of hot gas in large cosmic structures

    X-ray observations reveal the largest bound structures in the Universe and their evolution on cosmological timescales. IXO's unprecedented capabilities will enable us to confront the following key questions:


    • How did large scale structure evolve?
    • Where are the missing baryons in the nearby Universe?
    • What is the nature of Dark Matter and Dark Energy?


    Cosmic feedback in galaxies and clusters

    An extraordinary recent development in astrophysics has been the realization of the close linkage between the two dominant processes producing radiation in the Universe, namely fusion in stars, and accretion onto black holes. The physical process underpinning this relationship has become known as feedback, and the concept of cosmic feedback underpins many of IXO's key goals. The great leap forward in capabilities provided by this observatory will allow us to attack the feedback problem from several angles, to address the key underlying question:


    • How did feedback from black holes influence galaxy growth?