An artist’s impression of Athena, and the latest map of the X-ray sky (containing 375000 X-ray sources)
At its meeting in Paris today, the Science Program Committee of the European Space Agency (ESA) selected the "The Hot and Energetic Universe" as the science theme for its next Large (L-class) mission.
The mission is expected to be launched in 2028, with the power to address some of the most fundamental questions in modern astrophysics.
Hot gas in the universe is the dominant form of ordinary matter, the same material that everything we see around us is made from. The hot gas forms the largest structures in the visible universe, aggregated around clusters of galaxies. With temperatures of more than a million degrees, the gas emits copiously at X-ray wavelengths.
With the new mission, astronomers will measure the properties of galaxy clusters in the distant universe, and map the physical characteristics of the largest structures known—information dramatically advancing our understanding of how these structures first assembled when the universe was just two billion years old.
Mapping the motion, temperature and chemical composition of the hot gas and tracking it through cosmic time are crucial to understanding the evolution of the galaxies and stars we see today.
With the powerful new X-ray Observatory, astronomers will be able to look still further back, to observe the first supermassive black holes, and to a time when the first galaxies were forming, less than one billion years after the Big Bang.
It will take another 10 years or so to build the Observatory. In 2028, Athena should begin to reveal the hot and energetic universe in unprecedented detail, and provide an answer to that most basic question—why does the universe look like it does today.
