Roadmap Science Challenge
D:3. How do ultra-compact objects form, what is their nature and how does extreme gravity impact on their surroundings?
Although not directly observable, astronomers now believe that the existence of black holes in the Universe, including in our own Milky Way, is incontrovertible with evidence for black holes with masses from a few tens to a few millions of solar masses. While there is a plausible theory for the formation of stellar mass black holes through rapid gravitational collapse that leads to a supernova explosion, the formation of supermassive objects is highly uncertain but can be probed through their strong interaction with surrounding gas and stars which gives rise to the emission of gravitational waves and gamma rays. Astronomers are opening up these new windows to the Universe through the use of novel space and ground based facilities.