Supermassive black holes represent some of the most extreme objects in the cosmos, possessing gravitational pulls so immense that nothing, not even light, can escape their grasp. These enigmatic entities reside at the hearts of most large galaxies, profoundly influencing their surroundings. This article compares two cosmic titans: TON 618 and the central black hole of the Phoenix Cluster.
Unveiling TON 618
TON 618 is a supermassive black hole powering a hyperluminous quasar. A quasar is an extremely bright, active galactic nucleus where a supermassive black hole rapidly accretes gas and dust. This infalling material forms a swirling accretion disk, heating to extreme temperatures and emitting vast amounts of radiation, making the quasar incredibly luminous.
The black hole at the core of TON 618 is estimated to be approximately 66 billion times the mass of our Sun. It is located an immense distance from Earth, about 18.2 billion light-years away, meaning the light we observe today left TON 618 approximately 10.8 billion years ago. Its extreme luminosity, shining as brightly as 140 trillion Suns, allows it to be detected across such vast cosmic distances.
Exploring Phoenix A’s Central Black Hole
At the heart of the Phoenix Cluster, one of the most massive galaxy clusters known, lies a supermassive black hole often referred to as Phoenix A. This black hole plays a significant role in regulating star formation by influencing the surrounding hot gas.
The black hole in Phoenix A is estimated to possess a mass of around 100 billion solar masses. It resides within the central elliptical galaxy of the Phoenix Cluster, located approximately 5.7 to 5.8 billion light-years from Earth. Phoenix A’s black hole is observed actively interacting with the gas and star formation processes within its galaxy cluster environment.
The Direct Comparison: Which is Bigger?
When comparing TON 618 and Phoenix A, current estimates indicate that Phoenix A’s central black hole is significantly more massive, at around 100 billion solar masses, compared to TON 618’s approximately 66 billion solar masses. Phoenix A’s black hole currently holds the distinction as one of the largest known black holes.
“Bigger” for black holes primarily refers to their mass, which directly determines the size of their event horizon—the boundary beyond which nothing can escape. A more massive black hole will have a larger event horizon. The Phoenix A black hole, with its immense mass, has an event horizon that could engulf our entire solar system. Phoenix A’s black hole pushes closer to the theoretical upper limit for black hole growth, which some studies suggest could be around 100 billion solar masses.
Measuring the Unmeasurable: How We Estimate Black Hole Sizes
Astronomers cannot directly “see” black holes, as their gravitational pull prevents light from escaping. Instead, they rely on indirect methods to estimate the masses and “sizes” of these supermassive objects. These techniques observe the gravitational influence black holes exert on surrounding matter.
For active black holes like the one powering the TON 618 quasar, a primary method is reverberation mapping. This technique measures the time delay between variations in light from the inner accretion disk and “echoes” from gas clouds further out. By determining this delay and the speed of the gas, astronomers estimate the mass of the central black hole. For less active supermassive black holes, such as the one in Phoenix A, astronomers observe the motion of stars or gas within the galactic bulge around the black hole. By analyzing the orbital speeds and paths, scientists can infer the mass of the unseen object creating that gravitational pull. These methods provide robust estimates, though they are based on models and observations rather than direct measurement.
The Cosmic Context of Supermassive Black Holes
Supermassive black holes are integral to the evolution of galaxies. Their immense gravitational influence and the energetic output from their accretion disks can profoundly affect the formation of stars and the overall growth and structure of their host galaxies. This symbiotic relationship suggests that galaxies and their central supermassive black holes co-evolve over cosmic time.
These colossal objects are thought to have formed and grown through various processes, including the accretion of gas and dust and mergers with other black holes. While black holes like Phoenix A and TON 618 represent the upper echelons of mass currently known, ongoing research continues to unveil new discoveries and refine our understanding of how these extreme objects originate and shape the vast cosmic structures we observe today.