A simulation of a black hole quasar.
© NASA/ESA/CSA/Joseph Olmsted (STScI)
Quasar are the bright active centers of a galaxy and belong to the most powerful energy sources in the universe. They can shine as brightly as a trillion stars packed into a volume the size of our solar system. At the core of a quasar is a supermassive black hole.
How or how their intense activity is generated has remained a mystery since their discovery. The team of the two Universities Sheffield and Hertfordshire has now found that these objects are the result of galaxies colliding.
Energy in the form of radiation
The researchers made this discovery with the Isaac Newton Telescope in La Palma. The collision was noticed when they discovered distorted structures in the outer regions of the galaxies. In general, most galaxies contain large amounts of gas in addition to supermassive black holes. This usually orbits at a great distance from the center of the galaxy, beyond the range of the black holes.
When galaxies collide, the gas is pushed towards the black hole. Then the gas is gobbled up by the black hole. Enormous amounts of energy are released in the form of radiation. This leads to the extreme luminosity of the quasars.
When a quasar is “ignited” in this way, it can result in the rest of the gas being pushed out of the galaxy, preventing new stars from forming for billions of years.
creation of the universe
The researchers compared their observations of 48 quasars and their galaxies with images of more than 100 quasar-less galaxies. The team concluded that those galaxies that host quasars are about 3 times more likely to interact or collide with other galaxies.
“Quasars are one of the most extreme phenomena in the Universe, and what we’re seeing likely represents the future of our own Milky Way when it collides with the Andromeda Galaxy in about 5 billion years,” says Clive Tadhunter der University of Sheffield’s Department of Physics and Astronomy.
In general, quasars can provide information about the origin of the universe. The study was in Monthly Notices of the Royal Astronomical Society published.
