Galaxies are one of the most spectacular astrophysical objects and are essential building blocks of the Universe. They are characterised by rich diversity in size, colour and morphology, depending both on their local environment and on their evolutionary past. Galaxies provide us with invaluable clues as to the large scale properties of the Universe.
High Redshift Galaxies
Due to the time light takes to travel to us, we observe distant galaxies at high redshifts as they were in the past. By looking at these distant galaxies, particularly their structure, gas dynamics and chemical composition (metalicity), we can gain insight into how galaxies such as our own looked in the past and thus learn about the evolution of galaxies through the history of the Universe.
Quasars and active galaxies
Observations of very high redshift quasars indicate that the supermassive 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.
Galaxy Formation Simulations
Researchers at the IoA are developing sophisticated numerical models to follow the evolution of galaxies and their central black holes simultaneously, embedded in self-consistent cosmological simulations. These simulations give us valuable insight into the nature of black hole growth and feedback mechanisms, and at the same time are able to constrain which physical processes are governing the build-up of the galaxy population.
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