The black hole in Phoenix A (also known as the central supermassive black hole in the Phoenix Cluster) is one of the most massive black holes ever detected — and it’s associated with some truly extreme cosmic phenomena.
Here’s what we know:
🌌 What is Phoenix A?
- Phoenix A refers to the central galaxy in the Phoenix Cluster (catalogued as SPT-CLJ2344-4243), a massive galaxy cluster located in the constellation Phoenix, about 5.7 billion light-years from Earth.
- The Phoenix Cluster is one of the most massive and X-ray luminous clusters in the observable universe.
- Phoenix A is a brightest cluster galaxy (BCG) — the dominant galaxy at the heart of the cluster, sitting deep in its gravitational well.
🕳️ The Supermassive Black Hole
- In 2023, a study led by researchers using the Chandra X-ray Observatory and other data suggested that the black hole at the center of Phoenix A may have a mass of around:
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100 billion solar masses (10¹¹ M☉) - If confirmed, this would make it one of the largest black holes ever discovered, possibly a “ultramassive black hole.”
🔥 A Cosmic Engine: Enormous Power Output
- The Phoenix A black hole is actively accreting matter — feeding on gas at a very high rate.
- This accretion is powering enormous jets and outflows, creating cavities in the surrounding hot gas of the cluster — a process called AGN (Active Galactic Nucleus) feedback.
- The outflows from this black hole are releasing an astounding amount of energy, estimated to be:
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~10⁴⁶ ergs per second
(That’s roughly 100 trillion times the luminosity of the Sun.)
🧊 Cooling and Starburst Paradox
- Most galaxy clusters have cooling flows — gas cools and condenses onto the central galaxy — but AGN feedback often prevents runaway cooling and star formation.
- In the Phoenix Cluster, however:
- There is strong cooling of gas.
- Phoenix A is undergoing a massive starburst, forming up to 500 stars per year.
- This unusual combination — powerful black hole + active star formation — makes Phoenix A a paradox. Normally, such a powerful AGN would suppress star formation, not coexist with it.
🌌 Why Is This Important?
- It challenges our models of black hole feedback, cooling flows, and galaxy evolution in clusters.
- If the 100-billion-solar-mass estimate holds, it reshapes our understanding of how fast black holes can grow and whether such monsters could exist in other early massive galaxies.
🧭 Is It the Most Massive Black Hole?
- It’s in competition with other candidates like:
- TON 618 (a quasar with an estimated 66+ billion solar masses),
- IC 1101’s black hole (estimates vary from tens to over 100 billion),
- NGC 4889 and Holm 15A (both suspected to host ultramassive black holes).
- The Phoenix A black hole is a serious contender, and its environment makes it uniquely observable through its energetic feedback.
Would you like a comparison chart of known ultramassive black holes, or a breakdown of how these mass estimates are made (via stellar dynamics, X-ray cavities, or gravitational lensing)?
