Porphyrion is a Fanaroff–Riley class II

radio galaxy A radio galaxy is a galaxy with giant regions of radio emission extending well beyond its visible structure. These energetic radio lobes are powered by jets from its active galactic nucleus. They have luminosities up to 1039 W at radio wav ...

located 7.5 billion light years away from Earth, with host galaxy J152932.16+601534.4. It is located in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Draco DRACO (double-stranded RNA activated caspase oligomerizer) is a group of experimental antiviral drugs formerly under development at the Massachusetts Institute of Technology. In cell culture, DRACO was reported to have broad-spectrum efficacy aga ...

and it was discovered in

Low-Frequency Array The Low-Frequency Array (LOFAR) is a large radio telescope, with an antenna network located mainly in the Netherlands, and spreading across 7 other European countries as of 2019. Originally designed and built by ASTRON, the Netherlands Institute ...

(LOFAR) data by an international team led by Martijn Oei. Porphyrion has the longest jets of any radio galaxy identified, with lobed structures spanning across, making it the largest known structure of galactic origin. It superseded

Alcyoneus In Greek mythology, Alcyoneus or Alkyoneus (; ) was a traditional opponent of the hero Heracles. He was usually considered to be one of the Gigantes (Giants (Greek mythology), Giants), the offspring of Gaia (mythology), Gaia born from the blood o ...

, discovered by the same team in 2022, with lobed structures of .

Discovery

Porphyrion was first reported in a paper in ''

Nature Nature is an inherent character or constitution, particularly of the Ecosphere (planetary), ecosphere or the universe as a whole. In this general sense nature refers to the Scientific law, laws, elements and phenomenon, phenomena of the physic ...

'' by Martijn Oei (

Leiden University Leiden University (abbreviated as ''LEI''; ) is a Public university, public research university in Leiden, Netherlands. Established in 1575 by William the Silent, William, Prince of Orange as a Protestantism, Protestant institution, it holds the d ...

Caltech The California Institute of Technology (branded as Caltech) is a private university, private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small g ...

) and colleagues, which featured on the cover of the 19 September 2024 issue, after obtaining results from the Low Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS), an interferometric radio survey of the Northern Sky. Porphyrion was part of a large number of new giant radio galaxies discovered by this team. The giant black hole jet system was named after Porphyrion, a

Giant In folklore, giants (from Ancient Greek: ''wiktionary:gigas, gigas'', cognate wiktionary:giga-, giga-) are beings of humanoid appearance, but are at times prodigious in size and strength or bear an otherwise notable appearance. The word ''gia ...

from Greek mythology, by co-discoverer Aivin Gast from the

University of Oxford The University of Oxford is a collegiate university, collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the List of oldest un ...

. To find the galaxy from which Porphyrion originated, the

Giant Metrewave Radio Telescope The Giant Metrewave Radio Telescope (GMRT), located near Narayangaon, Pune in India, is an array of thirty fully steerable parabolic radio telescopes of 45 metre diameter, observing at metre wavelengths. It is the largest and most sensitive rad ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

was used along with ancillary data from the

Dark Energy Spectroscopic Instrument The Dark Energy Spectroscopic Instrument (DESI) is a scientific research instrument for conducting spectrographic astronomical surveys of distant galaxies. Its main components are a focal plane containing 5,000 fiber-positioning robots, and a bank ...

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

. The observations pinpointed to the galaxy J152932.16+601534.4, which is about 10 times more massive than the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

Characteristics

The team reporting the discovery described Porphyrion as a 'black hole jets system', rather than a giant

, as they considered the latter a confusing term: the jet structure of a radio galaxy is not formally part of the galaxy proper. Radio galaxies are a special class of objects characterized by the presence of radio lobes generated by

relativistic jets An astrophysical jet is an astronomy, astronomical phenomenon where outflows of Ionization, ionised matter are emitted as extended beams along the rotation, axis of rotation. When this greatly accelerated matter in the beam approaches the speed of ...

supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...

. Giant radio galaxies are different from ordinary radio galaxies in that they can extend to much larger scales, reaching upwards to several megaparsecs across, far larger than the diameters of their host galaxies. The

W. M. Keck Observatory The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes have aperture primary mirrors, and, when c ...

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

was used to show that Porphyrion is 7.5 billion light-years from Earth, and dates to a time when the universe was 6.3 billion years old. The observations also revealed that Porphyrion emerged from a radiative-mode active black hole, as opposed to one in a jet-mode state. Porphyrion's two jets combined have a jet power of 10³⁹ watts, equivalent to the energy output of trillions of suns. Oei and his colleagues believe that "every place in the universe may have been affected by black hole activity at some point in cosmic time". They suggest that giant jet systems like Porphyrion may have had a larger influence on the formation of galaxies in the young universe than previously believed, and suggest that these giant jets could have spread magnetism through the cosmos.

References

{{2024 in space Radio galaxies Active galaxies Astronomical radio sources Draco (constellation)

Discovery

Characteristics

See also

References