Institute of Astronomy

Quasars and active galaxies

Observations of nearby galaxies and high redshift quasars show that black holes are ubiquitous inhabitants of the vast majority of galaxies and that supermassive black holes, with masses in excess of billion Solar masses, already formed at the time when the Universe was less than 10% of it's current age.

Observations of very high redshift quasars indicate that the accreting black holes which are powering them have extreme properties: they are characterized by very high masses, in excess of a billion Solar masses, and they are very efficient accretors, close to the Eddington limit. The mere existence of these high redshift quasars and their accreting suppermassive black holes is a significant challenge for theoretical models, which need to explain how such massive object have managed to grow in less than a Gyr of cosmic time.

Quasar related research at the IOA focuses on a number of key themes.

  • Discovery of highest redshift quasars and with the goal of characterizing the Epoch of Reionization via the observation of intervening absorption lines
  • AGN and quasar formation, growth and feedback processes
  • Accurate super massive black hole masses
  • Gravitationally lensed quasars as probes of the distance scale and rate of expansion of the Universe, Dark Matter and Dark Energy and quasar host galaxies
Page last updated: 5 August 2021 at 14:51