Hot and full of energy

FAU to be involved in next big ESA mission

How did black holes form and how did they shape the universe? How did large structures form from regular matter as we see it today? These questions are among the most important of modern astrophysics and the European Space Agency’s next big mission could provide the answers we seek. FAU is one of three German universities to be involved in the international project. The research satellite will be launched in 2028.

The next big ESA mission will be about ‘the hot and energetic universe’, the organisation recently announced in Paris. The subject was proposed by an international collaboration including the team of FAU researchers led by Prof. Dr. Jörn Wilms of the Dr. Karl Remeis Observatory and the Erlangen Centre for Astroparticle Physics; the collaboration is headed by the Max Planck Institute for Extraterrestrial Physics in Garching. The researchers plan to use a special x-ray telescope called Athena to radiograph the universe with unprecedented accuracy and to find an answer to the question why our universe looks the way it does today. To find out how they will have to position the instruments, the FAU researchers simulate how the x-ray detectors will behave on the satellite.

Most of the universe’s regular matter is in hot, gaseous form. This fact is responsible for galaxy clusters, for instance, the largest connected structures that we know of today. At temperatures of more than ten million degrees Centigrade, the gas radiates especially strongly in the x-ray spectrum. If scientists want to understand how structures consisting of regular matter form and develop, they need an x-ray observatory in space with a high sensitivity, good spectral resolution and a large field of view.

And this is exactly what they designed Athena for. Astronomers can use a specially designed telescope such as this one to make spectroscopic observations of faraway galaxies and measure the physical parameters of the largest bound objects. This information would greatly advance our understanding of how the structures formed from hot gas during the universe’s infancy. Measurements of the speeds, the thermodynamics and the chemical composition of the hot gas as well as the changes in these parameters on a cosmic time scale would also give the researchers completely new insights into complex astrophysical processes.

With an x-ray telescope such as Athena, astronomers can actually look even further back into the history of the universe in order to examine its most energetic processes and discover the first supermassive black holes. These date to a time when the first galaxies were forming, less than one billion years after the Big Bang. Due to the extremely high temperatures and huge quantities of energy that matter gives off when it falls into a black hole, x-rays are the most reliable and comprehensive method with which to examine black holes.

However, large satellites, which cost about one billion euros, can only be built for especially important scientific questions. Therefore, ESA will select such a question every eight to ten years. Since the ESA’s scientific subject has now been decided, the plans for the satellite, which European x-ray astronomers have developed over the past 10 years, must be refined and the concept for the mission must be finalised. As the Athena team suggested the subject and since it is the only team in Europe with the required technology at their disposal, the scientists are confident that their concept will win.

ESA is expected to make this decision in 2014. This will be followed by three to four years during which the necessary technology is optimised. After that, it should take another ten years to complete the observatory. From 2028 on, Athena could be gazing out into the hot and energetic universe. The preparations for Athena at FAU were supported by the Deutsche Zentrum für Luft- und Raumfahrt (German Centre for Aeronautics and Space Research).

Further information:

Prof. Dr. Jörn Wilms
Phone: +49 (0)951 95222 13