Quasars, the most powerful objects in the universe, have been a mystery to astronomers for 60 years. Scientists have solved one of their biggest riddles when they learned that it was the merging of galaxies that ignited the quasars, the brightest and most powerful objects in the universe.
First described 60 years ago quasarshas the luminosity of a trillion stars concentrated in an area the size of our solar system. Since they were first noticed, what could cause such intense activity has remained a mystery. According to new research led by experts at the Universities of Sheffield and Hertfordshire, it has been discovered that this is the result of galaxies colliding with each other.
After noticing deformed patterns in the outer regions of quasar-hosting galaxies, the researchers used deep imaging studies from the Isaac Newton Telescope in La Palma to find collisions.
Supermassive black holes are found at the center of most galaxies. They also contain significant amounts of gas, but mostly this gas orbits far from galactic centers and is therefore out of range of black holes. The black hole at the heart of the galaxy is drawn into the gas by collisions between galaxies; Just before the gas is sucked into the black hole, it releases an enormous amount of energy in the form of radiation, giving the quasar its distinctive glow.
The appearance of a quasar could have serious implications for entire galaxies; It could expel the remaining gas of the galaxy, preventing it from producing new stars for billions of years.
This is the first time a quasar of this size has been observed at this sensitivity level. By comparing images of 48 quasars and their host galaxies with images of more than 100 non-quasar galaxies, the researchers concluded that galaxies hosting quasars are about three times more likely to interact or collide with other galaxies.
Thanks to the work, we now have a much better understanding of how these powerful things are initiated and nurtured.
"Quasars are one of the most extreme phenomena in the universe, and what we see is likely to represent the future of our own Milky Way galaxy when it collides with the Andromeda galaxy about five billion years from now," said Professor Clive Tadhunter of the University of Sheffield's Department of Physics and Astronomy.
Fortunately, Earth will not be exposed to one of these apocalyptic events for a long time. "It's exciting to observe these events and finally understand why they occur."
Quasars are important to astronomers because they shine at great distances because of their brightness and serve as beacons to the early universe.
A Postdoctoral Research Fellow at the University of Hertfordshire, Dr. “This is an area that scientists around the world want to learn more about,” says Jonny Pierce. “NASA's James Webb Space Telescope was designed to study the oldest galaxies in the universe, and Webb can detect light from even the most distant quasars that sprang up about 13 billion years ago. Our understanding of the past of the universe and perhaps even the future of the Milky Way depends heavily on quasars.
Source: phys.org/news
Günceleme: 28/04/2023 23:28