A black hole 40 billion times the sun’s mass challenges our cosmic understanding.
Key Takeaways
- Holm 15A’s central black hole is the largest ever measured at 40 billion solar masses.
- This black hole is comparable in mass to two-thirds of all stars in the Milky Way.
- Holm 15A likely formed from the collision of eight smaller galaxies over billions of years.
- The finding supports theories on quasars and the existence of ultra-massive black holes.
- Studying Holm 15A offers insights into galaxy mergers and the evolution of massive black holes.
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Astronomers have identified the largest black hole ever measured, nestled in the heart of Holm 15A, a massive elliptical galaxy located within the galaxy cluster Abell 85. The black hole boasts an incredible mass of 40 billion suns—comparable to two-thirds the mass of all stars in the Milky Way. This extraordinary discovery was detailed in a study set to appear in The Astrophysical Journal and currently available on the preprint site arXiv.
To measure this black hole’s mass, researchers used data from Holm 15A’s stellar orbits and constructed advanced models. This gargantuan black hole, which is roughly the size of our solar system, likely formed through multiple galaxy mergers.
The Formation of Holm 15A
Holm 15A’s immense size and faint central region suggest a history of successive collisions. When spiral galaxies like the Milky Way merge, they form elliptical galaxies. In dense galaxy clusters, these elliptical galaxies often collide again, creating even larger elliptical galaxies with “cored” centers—regions devoid of stars due to black hole activity.
Holm 15A likely resulted from the merger of two massive cored elliptical galaxies, which themselves formed from the collision of smaller galaxies. This sequence of events created Holm 15A and its central black hole over billions of years, consolidating the remnants of at least eight smaller galaxies.
Supporting Quasar Theories
Beyond its record-breaking size, this black hole lends critical support to theories about quasars—ultra-bright galaxies powered by supermassive black holes consuming nearby matter. Astronomers have long believed that black holes with masses exceeding 10 billion suns are necessary to explain quasar brightness. Holm 15A’s black hole confirms such black holes exist and validates models of quasar formation and black hole accretion.
Jens Thomas, an astronomer at the Max Planck Institute for Extraterrestrial Physics and co-author of the study, described the discovery as both “cool” and scientifically vital. Co-author Roberto Saglia highlighted that finding such a massive black hole nearby affirms existing theories on quasars and accretion processes.
The discovery of Holm 15A’s black hole not only deepens our understanding of galaxy evolution but also reinforces key ideas about the role of black holes in shaping the universe’s most luminous phenomena.
