A team of astrophysicists have reported the first definitive evidence of merging galaxies producing jets of charged particles, which can travel at nearly the speed of light.
Previously, scientists discovered that these jets could be found in elliptical-shaped galaxies, formed in the merger between two spiral galaxies. Scientists from Clemson University, USA, have since gained photographic evidence of the formation of a jet from two young spiral-shaped galaxies.
Vaidehi Paliya, a former Clemson post-doctoral researcher and lead author of the findings, said: “For the first time, we have found two spiral- or disk-shaped galaxies on path for a collision that have produced a nascent, baby jet that has just started its life at the centre of one of the galaxies.”
What are jets?
Associate professor, Marco Ajello, said that astrophysicists have previously captured images of galactic collisions, however, Ajello and his colleagues were the first to capture two galaxies merging producing fully formed jets of charged particles.
Jets of charged particles are believed to be the most powerful astrophysical phenomena in the universe, emitting more energy into the universe in one second than our Sun will produce in its lifetime.
Scientists hypothesised that jets are born from older elliptical-shaped galaxies with an active galactic nucleus (AGN), which is a supermassive black hole at its centre.
“Jets are the best accelerators in the universe – far better than the super colliders we have on Earth,” said assistant professor Stefano Marchesi of the department of physics and astronomy, referring to accelerators used in high-energy physics studies.
How do AGNs grow?
According to the research team, AGNs grow larger through a process called accretion, the gravitational gathering of gas and dust. Some particles become accelerated and are spewed onwards in narrow beams in the form of jets of charged particles.
Ajello explained: “It’s hard to dislodge gas from the galaxy and have it reach its centre… you need something to shake the galaxy a little bit to make the gas get there.
“The merging or colliding of galaxies is the easiest way to move the gas, and if enough gas moves, then the supermassive black hole will become extremely bright and could potentially develop a jet.”