A group of British astronomers has managed to solve the mystery of quasars, the most powerful and brightest objects in the Universe
Quasars shine as brightly as a trillion stars packed into a volume the size of our Solar System. They are the most powerful objects in the Universe, and until now it has been a mystery where that power came from. A group of astronomers from the Universities of Sheffield and Hertfordshire (United Kingdom) have now solved the riddle.
Quasars were first observed a few decades ago. Recently, scientists have obtained a better look at these phenomena thanks to the Isaac Newton Telescope located on La Palma, which has made it possible to discover their origin, one of the greatest mysteries of astronomy, and to decipher the possible future of our own Via milky
Quasars are ignited by colliding galaxies Most galaxies have supermassive black holes at their centers. They also contain substantial amounts of gas, but most of the time this gas is orbiting at great distances from the centers of galaxies, out of reach of black holes. Collisions between galaxies propel gas toward the black hole at the center of the galaxy. Just before the gas is consumed by the black hole, it releases extraordinary amounts of energy in the form of radiation, resulting in the quasar’s characteristic glow, the researchers explain in a statement.
The ignition of a quasar can have dramatic consequences for entire galaxies: it can expel the rest of the galaxy’s gas, preventing new stars from forming billions of years into the future.
This is the first time a quasar sample of this size has been imaged with this level of sensitivity. By comparing observations of 48 quasars and their host galaxies with images of more than 100 non-quasar galaxies, the researchers concluded that quasar-hosting galaxies are about three times more likely to interact or collide with other galaxies.
Our Milky Way is likely to experience its own quasar The study has provided an important step forward in our understanding of how these powerful objects are activated and powered. “Quasars are one of the most extreme phenomena in the Universe, and what we see likely represents the future of our own Milky Way galaxy when it collides with the Andromeda galaxy in about five billion years,” says Clive. Tadhunter, a professor in the Department of Physics and Astronomy at the University of Sheffield. “It’s exciting to watch these events and finally understand why they happen, but hopefully Earth won’t be anywhere near one of these apocalyptic episodes for quite some time.” Quasars reveal the history of the Universe Quasars are important to astrophysicists because, due to their brightness, they stand out at great distances and thus act as beacons for the earliest epochs in the history of the Universe. “It’s an area that scientists around the world are eager to learn more about: One of the main scientific motivations for NASA’s James Webb Space Telescope was to study the oldest galaxies in the Universe, and Webb is able to detect the light even from the most distant quasars, emitted almost 13 billion years ago,” says Jonny Pierce, a postdoctoral researcher at the University of Hertfordshire. “Quasars play a key role in our understanding of the history of the Universe, and possibly the future of the Milky Way as well.”
source: https://academic.oup.com/mnras/article/522/2/1736/7035603