Gargantuan. This is the term selected by American and European astrophysicists to characterize their latest discovery: a pair of plasma jets emerging from a black hole, stretching over a distance of 23 million light-years. To put this in perspective, this length is akin to lining up 140 galaxies, each with a diameter comparable to that of the Milky Way, one after another. Unsurprisingly, these jets are the longest ever recorded escaping from a black hole.
The galaxy that contains the supermassive black hole is located at the center of the image, with the brighter spot indicating a foreground galaxy. Photo: LOFAR/Martijn Oei. The Milky Way would be represented as a small point within these two colossal eruptions, observes Martijn Oei, an astrophysicist affiliated with the California Institute of Technology (CALTECH) and the lead author of the discovery published in the journal Nature. According to the researchers, this gigantic jet structure, named Porphyrion after the giant from Greek mythology, originated when the Universe was 6.3 billion years old, which is half its present age of 13.8 billion years. This research is significant as it provides insights into the history of the Universe as well as the formation and evolution of galaxies over time. It came as a surprise, since most active galaxies are typically observed in the nearby Universe, says Marine Prunier, a doctoral student in astrophysics at the University of Montreal, who was not involved in the study. There are extremely ancient galaxies that already have supermassive black holes from the early Universe, and they are quite large. It remains a mystery!
Key Concepts
A black hole is a celestial object with an extraordinarily large mass confined to a small volume, akin to the Sun being only a few kilometers wide or the Earth compressed into the head of a pin. Black holes are so massive that nothing can escape them, not even light. Consequently, they are nearly invisible, so much so that no telescope succeeded in directly observing one until 2019. Stellar black holes arise when stars die, typically having a mass between 10 to 20 times that of the Sun. The formation of intermediate black holes, with masses ranging from 100 to 10,000 solar masses, remains poorly understood. The birth of supermassive black holes, found at the centers of galaxies, is also shrouded in mystery, with masses potentially ranging from millions to billions of times that of the Sun. Although black holes are known for consuming matter nearby, they can also emit powerful jets of matter that extend far beyond the galaxies they inhabit. Currently, it is estimated that about 20% of supermassive black holes emit jets. No jets have been observed coming from Sagittarius A*, the black hole at the center of our Milky Way.
More Discoveries
The Porphyrion jet system was uncovered during a sky survey conducted using the European LOFAR (LOw Frequency ARray) radio telescope, which has revealed over 10,000 faint megastructures thus far.
LOFAR consists of 50,000 antennas organized into 48 stations across five European countries. Photo: LOFAR. Prior to this discovery, hundreds of larger jet systems had been detected, but these were generally much smaller than the thousands of systems found using the radio telescope. Before this finding, the largest detected jet system was Alcyonea, also named after a giant from Greek mythology. Discovered in 2022 by the same team, this system spans the equivalent of one hundred Milky Way-sized galaxies.
In contrast, the large Centaurus A jet system, which is closest to Earth, extends across roughly ten galaxies with a diameter similar to that of the Milky Way.
Mysterious Structures
While scientists still do not fully understand the formation of supermassive black holes, mergers with other types of black holes could be a potential source. The nature of jets also remains poorly documented, though some clues exist, notes Marine Prunier. A black hole accumulates matter and gas from its surroundings. These components end up rotating around it, forming an accretion disk that heats up and emits light.
The rotation of this accretion disk is believed to generate strong magnetic fields, ultimately resulting in the formation of perpendicular jets, summarizes Marine Prunier. Interestingly, the black hole responsible for the dual jets resides in a very dense area with only a few galaxies orbiting each other. Typically, however, black holes with jets are found in far larger galaxy clusters that contain thousands of galaxies in less dense environments.
Effects on the Cosmic Web
The researchers of this study propose that galaxies and their central black holes evolve together. They suggest that the jets emit immense amounts of energy, influencing the growth of the host galaxies as well as nearby ones. Furthermore, the discovery of this gargantuan celestial duo implies that large jet systems may have had a more significant impact on galaxy formation in the early Universe than previously believed. What makes this research particularly noteworthy is that it demonstrates the substantial effects of these jets on the cosmic web. The activity of a single black hole could potentially affect extremely large scales, perhaps impacting the very evolution of the Universe, asserts Marine Prunier. The team explains that Porphyrion existed at a time when the filaments connecting and energizing galaxies—known as the cosmic web—were closer together than they are today. This likely indicates that the gigantic jets influenced a larger portion of the cosmic web compared to the current jets observed in the nearby Universe.
The doctoral student explains that the jets produced by black holes heat the surrounding galactic environment, inhibiting the formation of new stars. Galaxies with jets from black holes are typically older and tend to produce fewer stars. They are gradually aging, notes Marine Prunier. If our Milky Way, a spiral galaxy known for star formation, were to host a jet of this nature at its core, it would undoubtedly hasten its transition towards a more elliptical galaxy, explains the doctoral student. Yet, the phenomenon is not straightforward; a localized jet could potentially create stars at its end by compressing gas, leading to cloud formations that collapse and give rise to new stars.
A Hypothesis to Explore
Additionally, observations made using the WM Keck Observatory indicate that Porphyrion originates from an active black hole in radiative mode, as opposed to jet mode. It is important to note that when supermassive black holes become active—when their gravitational forces act upon surrounding matter and heat it—they emit energy in the form of radiation or jets. Researchers estimate that black holes in radiative mode were more prevalent in the early Universe, while those in jet mode are more commonly found in the present Universe. However, the revelation that Porphyrion emerges from a black hole in radiative mode has surprised astronomers, who were unaware that this mode could generate such vast and powerful jets. Furthermore, since Porphyrion is situated in the young Universe, where radiative-mode black holes are abundant, this discovery suggests that there could be many more colossal jets yet to be identified.
We may only be seeing the tip of the iceberg, says Martijn Oei. Our study conducted with PROMISES only covered 15% of the sky. Given that most of these gigantic jets are likely difficult to detect, we suspect numerous similar behemoths remain hidden in the cosmos.
Regardless, astrophysicists still do not comprehend how jets can extend such vast distances beyond their host galaxies without destabilization. In future research, the authors aim to gain a deeper understanding of how these megastructures influence their environment. They plan to investigate the extent to which the giant jets propagate magnetic fields. The magnetism present on our planet facilitates the development of life, which is why we seek to understand its origins. Martijn Oei poses the question: Did these giant jets disseminate magnetism throughout the cosmos?
The very first direct image of matter being ejected from a black hole was obtained in November 2022.
Gargantuan: Discovery of Massive Plasma Jets from a Black Hole
The Discovery of Gargantuan Jets
Astrophysicists from America and Europe have unveiled an extraordinary discovery—a pair of plasma jets, referred to as “Gargantuan,” emanating from a black hole over a staggering distance of 23 million light years. This immense length could be likened to a line-up of approximately 140 galaxies with diameters similar to that of our Milky Way, making it the longest jets ever observed escaping from a black hole.
Characteristics of Gargantuan Jets
The researchers named this remarkable jet system Porphyrion, in homage to the giant from Greek mythology. This structure dates back to a period when the universe was merely 6.3 billion years old, which is about half its current age of 13.8 billion years. Martijn Oei, an astrophysicist affiliated with the California Institute of Technology (Caltech) and lead author of the study published in the journal Nature, emphasizes the newfound insights into the cosmos and how these jets potentially shape galactic formation and evolution.
Understanding Black Holes and Jets
Black holes are astronomical entities with incredibly large masses concentrated in a tiny volume. A black hole can possess the mass of the Sun compressed into just a few kilometers, resulting in gravitational forces so intense that not even light can escape. Consequently, they remain predominantly invisible.
Types of Black Holes
- Stellar Black Holes: Formed at the end of a massive star’s life, typically 10 to 20 solar masses.
- Intermediate Black Holes: 100 to 10,000 solar masses, still not well-understood.
- Supermassive Black Holes: Residing at the centers of galaxies, ranging from millions to billions of solar masses.
Why Gargantuan Jets Matter
These findings are vital for several reasons:
1. Historical Insights
They shed light on the evolution of the universe, particularly during its formative years. The presence of such massive structures indicates that supermassive black holes developed much earlier in cosmic history than scientists previously thought.
2. Galaxy Formation and Evolution
The jets from black holes have profound effects on their host galaxies and can influence the growth, structure, and star formation rates. It’s believed that black holes and galaxies develop in tandem, and the energy from jets can hinder star formation, leading to the aging of galaxies.
3. Cosmic Web Interactions
The discovery implies that these giant jets may have played a more significant role in shaping the cosmic web—the network of filaments connecting galaxies—than previously understood. The activity of black holes could resonate on galactic and cosmic scales, influencing the very structure of the universe.
Observing Gargantuan Jets: A Breakthrough with LOFAR
The Gargantuan jet system was identified while conducting sky surveys with the European LOFAR (LOw Frequency ARray) radio telescope, which has revealed more than 10,000 megastructures to date. This innovative instrument comprises 50,000 antennas distributed across five European countries, enabling unprecedented detection sensitivity.
Comparison with Recent Discoveries
The newly discovered Porphyrion jet system dwarfs previous finds, such as the Alcyonea jet system (also named after a giant), which spans only about 100 galaxies. The closest significant jet system, Centaurus A, extends roughly over ten Milky Way-sized galaxies.
The Mystery of Jet Formation
Despite progress in understanding black holes and jets, numerous questions remain. The mechanism behind jet formation is particularly enigmatic. Scientists believe that as black holes accrete surrounding matter, it forms an accretion disk, generating strong magnetic fields that contribute to the creation of powerful jets.
Key Factors in Jet Formation
- Accretion Disk: Surrounding gas and matter heats up and emits energy.
- Magnetic Fields: Strong magnetic forces are thought to be responsible for directing jets away from the black hole.
The Energetic Influence of Gargantuan Jets
The jets associated with black holes like Porphyrion are believed to emit enormous amounts of energy, significantly influencing the growth and evolution of their surrounding environments. As Marine Prunier, a doctoral student in astrophysics at the University of Montreal, notes, these jets can heat the galactic medium, suppressing new star formation and contributing to the aging process of their host galaxies.
Potential Effects on the Milky Way
If a powerful jet akin to those of Porphyrion were positioned at the center of our Milky Way, it might accelerate its transition towards a more elliptical galaxy, inhibiting star production. However, it’s worth noting that jets can also compress gas at their ends, potentially fostering new star formation under certain conditions.
What Lies Ahead?
As researchers continue to explore the implications of this discovery, they hope to unravel how massive jets like Porphyrion influence their environments, particularly regarding magnetism and its role in galactic evolution. The observation of Porphyrion emerging from a black hole in a radiative mode raises further questions about the mechanisms behind jet creation, particularly in the context of early cosmic environments.
Future Endeavors
Continuing studies may uncover additional colossal jets, as Martijn Oei suggests we may have only witnessed the tip of the iceberg. Only 15% of the sky was surveyed in the initial study, indicating that numerous massive jet systems are yet to be discovered.
Conclusion
The exploration of Gargantuan jets significantly enhances our understanding of astronomical phenomena and the broader cosmos. The findings may reveal how ancient black holes influenced their surrounding galaxies and the universe’s structure, paving the way for future research and discoveries in astrophysics.
