Newly discovered massive black holes located away from the centre of their respective galaxies may give us vital clues about how black holes formed in the early Universe.

Artist’s conception of a dwarf galaxy, its shape distorted, most likely by a past interaction with another galaxy, and a massive black hole in its outskirts (pullout). The black hole is drawing in material that forms a rotating accretion disc and generates jets of material propelled outward. Image credit: Sophia Dagnello, NRAO/AUI/NSF

The observation of 13 newly discovered massive black holes in dwarf galaxies less than a billion-light-years from earth could aid scientists’ understanding of the mechanism that lies beneath the formation of such black holes in the young universe. Even though we understand the mechanism behind the formation of black holes in later epochs of the universe, how massive primordial black holes — or ‘seed’ black holes — formed is still something of a mystery.

The dwarf galaxies in question are over 100 times less than the mass of the Milky Way and as such, are the smallest galaxies observed to possess a black hole. These black holes are theorised to possess a mass equivalent to 4x10⁵ solar masses — or 400,000 of our Suns.

“We hope that studying them and their galaxies will give us insights into how similar black holes in the early Universe formed and then grew, through galactic mergers over billions of years, producing the supermassive black holes we see in larger galaxies today, with masses of many millions or billions of times that of the Sun,” explains Amy Reines of Montana State University.