Quasars (quasi-stellar objects) are among the most energetic and mysterious phenomena in the universe. They are powered by supermassive black holes at the centers of distant galaxies, where matter falling into the black hole releases an enormous amount of energy, outshining the rest of the galaxy.
1. 3C 273
Location: Constellation Virgo | Distance: ~2.4 billion light-years
3C 273, discovered in 1963, was the first quasar to be identified, marking a breakthrough in astronomy. It remains one of the brightest quasars visible from Earth, with a jet of plasma extending for over 200,000 light-years. Observations from the Very Large Telescope (VLT) and Hubble Space Telescope have helped confirm that its energy output comes from the intense accretion of matter onto a supermassive black hole. This quasar was pivotal in proving that these objects are not stars but distant, active galactic nuclei.
2. TON 618
Location: Constellation Canes Venatici | Distance: ~10.4 billion light-years
TON 618, one of the most massive black holes known, weighs around 66 billion times the mass of the Sun. This quasar radiates with extraordinary luminosity, making it visible across vast cosmic distances. Its discovery during a radio survey in the 1970s helped confirm that some quasars host unimaginably large black holes. TON 618’s extreme size challenges our understanding of how black holes grow and evolve, as it must have accreted matter at an extraordinary rate in the early universe.
3. ULAS J1342+0928
Location: Boötes | Distance: ~13.1 billion light-years
ULAS J1342+0928 is one of the most distant quasars ever discovered, with light that has traveled for over 13 billion years to reach us. Its discovery in 2017 opened a new window into the early universe, showing that supermassive black holes existed just 690 million years after the Big Bang. This quasar plays a crucial role in studying the epoch of reionization—a time when the first stars and galaxies began to illuminate the dark universe.
4. HE 1104-1805
Location: Constellation Crater | Distance: ~10 billion light-years
HE 1104-1805 is a gravitationally lensed quasar, with its light distorted by an intervening galaxy, creating multiple images of the same object. This phenomenon allows astronomers to measure cosmic distances and study the structure of the universe. Observations in 2022 using the Hubble Space Telescope have also revealed changes in the quasar’s brightness over time, helping researchers better understand the physics of accretion disks and black hole feeding processes.
5. APM 08279+5255
Location: Constellation Lynx | Distance: ~12 billion light-years
APM 08279+5255 is known for its incredible luminosity, once thought to be the brightest object in the universe. This quasar is magnified by gravitational lensing, which makes it appear even brighter to observers on Earth. Further studies have revealed that it hosts one of the largest reservoirs of water vapor ever detected in space, with the water surrounding the black hole in a region hundreds of light-years wide. This discovery offers insight into the complex environments around quasars.
6. J0313-1806
Location: Pisces Eridanus Supervoid | Distance: ~13 billion light-years
Discovered in 2021, J0313-1806 is notable for having the earliest known supermassive black hole, forming less than 700 million years after the Big Bang. Its existence poses a challenge to current models of black hole growth since it appears to have grown to over a billion solar masses in such a short time. This discovery hints at possible alternative mechanisms for the rapid growth of black holes in the early universe.
7. PKS 0637-752
Location: Constellation Mensa | Distance: ~7.8 billion light-years
PKS 0637-752 is a radio-loud quasar known for its colossal jets of plasma extending for millions of light-years. Observations with the Chandra X-ray Observatory have revealed that the jets emit powerful X-rays, providing clues about how supermassive black holes expel energy. The quasar serves as a prime example of how these objects shape their host galaxies, influencing star formation by injecting vast amounts of energy into the surrounding environment.
Quasars illuminate the early cosmos, provide insight into the formation of supermassive black holes, and offer clues about the structure of galaxies and intergalactic space. With continuing advancements in observational technology, such as the James Webb Space Telescope, astronomers are poised to uncover even more about these enigmatic objects.