A team of Clemson University College of Science researchers, in collaboration with international colleagues, has reported the first definitive discovery of a relativistic jet originating from two colliding galaxies – essentially the first photographic evidence that merging galaxies can produce rays with charged particles traveling at almost the speed of light.
Furthermore, researchers had previously discovered that these jets could be found in elliptical shaped galaxies, which can be formed in the merger of two spiral galaxies. Now they have a picture showing the formation of a jet from two younger, helical galaxies.
“For the first time, we have found two spiral or disc-shaped galaxies on the way to a collision that has created an emerging, baby beam that has just begun its life in the middle of one of the galaxies,” said Vaidehi Paliya, a former Clemson postdoctoral fellow and lead author to the findings reported in Astrophysical Journal on April 7, 2020.
The paper is entitled “TXS 2116-077: A gamma ray emitting relativistic jet hosted in a galaxy fusion.” In addition to Paliya, who is now at the Deutsches Elektron Synchrotron (DESY) in Germany, the other Clemson authors include Associate Professor Marco Ajello, Professor Dieter Hartmann and Adjunct Professor Stefano Marchesi at the Department of Physics and Astronomy.
The fact that the jet is so young enabled scientists to clearly see their host.
According to Ajello, others have already depicted galactic collisions many times. But he and his colleagues are the first to capture two galaxies that merge where there is a fully formed beam pointing towards us – albeit a very young one, and thus not yet enough light to blind us.
“Usually, a jet emits light that is so powerful that we can’t see the galaxy behind it,” Marchesi said. “It’s like trying to look at an object and someone points a bright flashlight in your eyes. All you can see is the flashlight. This jet is less powerful, so we can actually see the galaxy where it was born.”
Rays are the most powerful astrophysical phenomena in the universe. They can release more energy into the universe in a second than our sun will produce throughout its lifetime. That energy is in the form of radiation, such as intense radio waves, X-rays and gamma rays.
“Rays are the best accelerators in the universe – much better than the super colliders we have on Earth,” Hartmann said, referring to accelerators used in high-energy physics studies.
Rays were thought to be born from older elliptical shaped galaxies with an active galactic core (AGN), which is a supermassive black hole located in the center. As a reference, scientists believe that all galaxies have centrally located supermassive black holes, but not all are AGN. For example, our milk road’s massive black holes are dormant.
Researchers theorize that AGNs become larger by gravitationally drawing gas and dust through a process called accretion. But not all of this issue is united in the black hole. Some of the particles are accelerated and spewed outwards in narrow beams in the form of rays.
“It’s hard to remove gas from the galaxy and get it to its center,” Ajello explained. “You need something to shake the galaxy a bit to get the gas there. Joining or colliding galaxies is the easiest way to move the gas, and if enough gas moves, the super-massive black hole will become extremely light and potentially developing a jet. “
Ajello believes the team’s image captured the two galaxies, a Seyfert 1 galaxy known as TXS 2116-077 and another galaxy of similar mass, as they collided for the second time due to the amount of gas seen in the image.
“Eventually, all gas will be released into space, and without gas, a galaxy can no longer form stars,” Ajello said. “Without gas, the black hole will shut down and the galaxy will be dormant.”
Millions of years from now, our own dairy will merge with the nearby Andromeda galaxy.
“Researchers have conducted detailed numerical simulations and predicted that this event could eventually lead to the formation of a giant elliptical galaxy,” Paliya said. “Depending on the physical conditions, it may be a relativistic jet, but it is in the distant future.”
The team captured the image with the help of one of the largest land-based telescopes in the world, the Subaru 8.2-meter optical infrared telescope located on a mountain peak in Hawaii. They made subsequent observations with the Gran Telescopio Canarias and the William Herschel telescope on the island of La Palma off the coast of Spain, as well as with NASA’s Chandra X-Ray Observatory space telescope.
Picture: Hubble looks at the fluffy look
Vaidehi S. Paliya et al, TXS 2116−077: A Gamma-Ray relative radiation hosted in a Galaxy fusion, The Astrophysical Journal (2020). DOI: 10.3847 / 1538-4357 / ab754f
First photo proof of powerful jet coming from colliding galaxies (2020, April 7)
retrieved April 7, 2020
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