Using a telescope in Chile, astronomers have captured a high-speed collision between two galaxies located more than 11 billion light-years away, getting a rare direct glimpse into how the universe’s most luminous sources of energy, known as quasars, can sculpt their surroundings and influence the evolution of galaxies.
The new findings describe a galactic battle between the galaxy on the right in the image above, which hosts an actively feeding black hole, a quasar, at its center, and its neighbor on the left, which is being bombarded by intense radiation that disrupts its ability to form new stars.
“We hence call this system the ‘cosmic joust,'” Pasquier Noterdaeme, a researcher at the Institut d’Astrophysique de Paris in France, who co-led the new study, said in a statement.
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Named J012555.11−012925.00, the quasar is generally so bright that it outshines its surroundings, dominating optical images as a single point of light. However, using the Atacama Large Millimeter/submillimeter Array (ALMA), a network of 66 radio dishes in the Chilean Andes working together as one giant telescope, astronomers were able to distinguish the second galaxy.
The observations revealed the companion galaxy is moving toward the quasar-hosting galaxy at about 1.2 million miles per hour (2 million kilometers per hour), indicating the two are in the midst of a high-speed collision.
This wide-field view shows the region of the sky around a pair of interacting galaxies, nicknamed the ‘cosmic joust’, in which one of them is piercing the other with intense radiation. The galaxies appear as a tiny white dot at the center of this image. (Image credit: DESI Legacy Survey)
To study how the quasar’s radiation affects the companion galaxy, the researchers used the X-shooter instrument on the Very Large Telescope (VLT), also located in Chile. By analyzing the quasar’s light as it passed through the other galaxy, they found the radiation blasts apart the gas in the companion galaxy, leaving behind compact cloudlets that are too small to form new stars.
“We see for the first time the effect of a quasar’s radiation directly on the internal structure of the gas in an otherwise regular galaxy,” Sergei Balashev, a researcher at the Ioffe Institute in Russia, who co-led the study, said in the statement.
The gravitational forces at play are also pulling more gas toward the black hole, allowing it to continue feeding and powering the quasar, the study found.
“These mergers are thought to bring huge amounts of gas to supermassive black holes residing in galaxy centres,” said Balashev.
The study was published on Wednesday (May 21) in the journal Nature.
