Friday, 2 October 2020

Astronomers Spot Ancient Galaxies in a Supermassive Black Hole ‘Spider Web’

With the help of ESO’s Very Large Telescope (VLT), astronomers have found six galaxies lying around a supermassive black hole, the first time such a close grouping has been seen within the first billion years of the Universe. This artist’s impression shows the central black hole and the galaxies trapped in its gas web. The black hole, which together with the disc around it is known as quasar SDSS J103027.09+052455.0, shines brightly as it engulfs matter around it.

The speed of light is a major inconvenience when you’re trying to land robots on another planet, but it’s a big help if you want to study the history of the universe. By peering into the far-away reaches of the cosmos, astronomers can see what the universe looked like millions or billions of years ago. A team using the European Southern Observatory’s (ESO) Very Large Telescope has spotted something unexpected: a cluster of six ancient galaxies caught in the gravity of a supermassive black hole. 

This study, led by astronomer Marco Mignoli from the National Institute for Astrophysics in Italy, sought to shed light on how objects like supermassive black holes could have developed in the early universe. To that end, the team used the Very Large Telescope (VLT) to scan a part of the universe more than 12 billion light years away. These objects, therefore, appear as they were just 900 million years after the Big Bang. 

In this early era of the universe, there would have been very few stars old enough to collapse into black holes. Astronomers have also struggled to explain how a black hole could accumulate so much mass in such a short time to become “supermassive.” The latest VLT discovery could help explain that. The central black hole discovered in this complex system had a mass of about a billion suns, and the galaxies surrounding it are embedded in a “spider’s web” of gas. The web crisscrosses a region of space more than 300 times the size of the Milky Way. 

According to the study, the team believes these streams of gas would have acted as conduits that allowed gas to move freely between the galaxies and the black hole. This could have supplied the singularity with all the matter it needed to bulk up in just a few hundred million years.

Assuming this study is accurate, we still need to figure out how this web of gaseous filaments formed. The team speculates dark matter might be the key. We know that this invisible material has gravitational effects on other matter, and many scientists believe it could have attracted large volumes of gas in the early universe. Could the galactic tendrils observed with the VLT have been bound together by dark matter? Maybe, according to Colin Norman of Johns Hopkins University. “Our finding lends support to the idea that the most distant and massive black holes form and grow within massive dark matter halos in large-scale structures, and that the absence of earlier detections of such structures was likely due to observational limitations,” he said. 

This study involved some of the dimmest objects visible with our current technology. It took many hours with the largest telescopes on Earth to gather data on the web of gas around this black hole. More powerful telescopes like the upcoming ESO Extremely Large Telescope and the James Webb Space Telescope might get us the rest of the way there.

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