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Astronomers have discovered the most distant and oldest single source of radio broadcasts in the known universe. This source is one of the most powerful particle accelerators in the universe: a quasar 13 billion light years from Earth spewing out jets of particles at almost the speed of light.
Quasars are among the oldest, most distant, most massive and brightest objects in the universe. They constitute the nuclei of galaxies where a rapidly rotating supermassive black hole is filled with all the matter that cannot escape its gravitational grip. As the black hole devours this material, it also emits a tremendous amount of radiation which collectively may be over a trillion times brighter than the brightest stars, making quasars the brightest objects in the world. observable universe.
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“[G]Since these objects are so bright, they can be observed very far away, “Chiara Mazzucchelli, who led the discovery with Eduardo Bañados, told Live Science.” When galaxies like the Milky Way are too faint to be detected and studied at distances, we can use these very bright quasars to study when the universe was very young. We are talking about a time when the first stars and galaxies were formed. “
This quasar in particular, named P172 + 18, is a relic of around 780 million years later. the Big Bang and reveals clues to one of the first ages of the universe – the reionization period. At the start of this period, the universe was obscurely obscured by an essentially uniform cloud of hydrogen gas. Scientists call this time the dark age of the universe because most of the light emitted was quickly absorbed by the gas with a neutral charge. Eventually gravity collapsed the primordial gas in the first stars and quasars, which began to heat and ionize the surrounding gases, allowing light to pass through.
Mazzucchelli, an astronomer at the European Southern Observatory in Chile, and Bañados, an astronomer at the Max Planck Institute for Astronomy in Germany, spotted the quasar for the first time using Magellan telescopes at the Las Campanas Observatory in Chile. They observed the telltale radio signature left by powerful jets of erupting particles above and below the black hole. Ultra-fast particles emit an enormous amount of radio waves. Scientists call these quasars “radio-noisy” and believe that their accelerated particle jets, which are only visible in about 10% of quasars, play a central role in the evolution of the first galaxies.
Other telescope observations, including the Keck Observatory in Hawaii and the Very Large Telescope in Chile, have shown that P172 + 18 is nearly 300 million times more massive than the sun and is among the fastest growing quasars fastest ever discovered. The problem is, scientists don’t know how a black hole got so massive so early in the universe. Radio jets could be one explanation.
“Theoretical studies indicate that the presence of radio jets can increase the rate at which the black hole eats matter, which means they can allow a black hole to grow much faster and could explain why [the black holes] are so massive so early on, “Mazzucchelli said.” At the same time, radio jets can also impact the galaxy surrounding the quasar by influencing star formation. “
However, the black hole’s binge eating may not have lasted long. When astronomers compared their most recent observations to a study of the sky taken more than two decades earlier, they found that the quasar had lost half of its luminosity, signaling that the quasar may be reaching the last stages of its life. .
Beacons in the dark
Mazzucchelli described quasars as distant flashlights that illuminate a specific time and space in the history of the universe. Each new quasar discovered reveals another patch in the timeline between the Big Bang and the universe we see today. She hopes the research team will find many more quasars nearby in the future.
In fact, shortly after their discovery of P172 + 18, astronomers found a second radio wave beacon nearby. If new observations confirm that this companion radio source is at the same distance as the quasar, it could be the most distant pair of active galaxies ever discovered. Researchers hope telescopes such as NASA’s James Webb Space Telescope will be able to determine the exact distance from the radio source.
The researchers’ results will be published in an upcoming issue of The astrophysical journal.
Originally posted on Live Science.
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