They are bright and vibrant and are found in the centers of galaxies. But until recently it was not clear how quasars ignite. Now researchers have an answer.
Sheffield/Hertfordshire – Quasars are the brightest and most active objects in the universe – but their origin was not known for a long time. However, researchers have recently begun to think they know what makes celestial objects glow. High luminosity is the hallmark of a quasar. It is located in the center of the galaxy and is its active nucleus.
Its visible light appears almost as a point, like a star. In addition to visible light, it emits large amounts of energy at other wavelengths. The name Quasar is derived from the English term “quasar radio source”, i.e. “star-like radio source”.
The radiation from the quasar comes from a rotating disk filled with matter orbiting a supermassive black hole at the center of the galaxy. Celestial bodies can shine as brightly as a trillion stars in an area the size of our solar system. To classify dimensions: There is only one star in our solar system, which is the Sun. Our Milky Way Galaxy is home to at least 100 billion stars.
For a long time it remained a mystery: how are quasars ignited?
Researchers know what a quasar is, but how it “ignites” has long been a mystery. However, a research team from the Universities of Sheffield and Hertfordshire recently solved this puzzle. It was the study In the specialized magazine Monthly Notices of the Royal Astronomical Society published. To do this, the researchers observed 48 different galaxies containing quasars and compared them to more than 100 galaxies that do not have quasars at their centers.
Astronomers have found that galaxies that host quasars are about three times more likely to interact or collide with other galaxies than galaxies that do not contain a quasar. The research team concludes that colliding galaxies may be responsible for the ignition of quasars.
The collision of two galaxies is said to ignite quasars
The researchers’ theory of how a galaxy’s collision could be ignited by a quasar seems harsh: There are large amounts of gas in the galaxy, which is usually far from the black hole at the galaxy’s center. A collision between two galaxies pushes gas closer to the black hole. Before the black hole swallows the gas, it releases large amounts of energy in the form of radiation – the characteristic glow of a quasar.
This flare-up could have catastrophic consequences for the entire galaxy: If the galaxy loses all its gas, new stars won’t be able to form there for billions of years.
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Quasars are extreme phenomena in the universe
“Quasars are one of the most extreme phenomena in the universe, and what we see is likely to represent the future of the Milky Way when it collides with the Andromeda Galaxy in about five billion years,” notes co-author Clive Tadhunter in his article. notice. The researcher is happy: “It is exciting to observe these events and finally understand why they happen – but fortunately, Earth is not close to one of these horrific events.”
Quasars are particularly interesting to research because their brightness means they can be seen over great distances and they can serve as “beacons” from the earliest times of our universe. “Quasars play a key role in our understanding of the history of the universe and perhaps also the future of the Milky Way,” explains co-author Johnny Pearce. Space organizations NASA, ESA and the Canadian Space Agency have highlighted the most distant quasars, which formed approximately 13 billion years ago. (unpaid bill)