There are trillions of galaxies in our Universe! Most of them, if not all, host at their centre a supermassive black hole, millions or even a billion times heavier than our Sun. However, most of them are dormant. Only about 1 in 10000, are active, i.e. accreting material and growing at a significant rate. Is there a feeding mechanism that activates them or active black holes occur naturally during the lifetime of a galaxy? This open question is further discussed here. 

The X-ray observatory ATHENA, scheduled to launch in a decade, will provide both the quality and quantity of observations that will allow astronomers to study the role of the environment on the activation of supermassive black holes. 

ATHENA Nuggets aim to present scientific and technical topics related to the ATHENA satellite and high-energy astrophysics to the non-experts. They are an initiative of the Athena Community Office (ACO) in collaboration with members of the Athena Community. ACO aims to promote, organise and present ATHENA related science to the general public. For more information see here and here.

For a lecture on black holes, by Prof. Andy Fabian visit here.