The Nobel-Prize laurate, Subrahmanyan Chandrasekhar in “The Mathematical Theory of Black Holes” (for whom NASA’s Chandra Space Observatory was named), described supermassive black holes as “the most perfect objects there are in the universe –the only elements in their construction are our concepts of space and time.” Some have described these cosmic monsters as the “Gates of Hell” and others as “gateways to another universe” and the largest hard disk that exists in nature, in two dimensions.
“Stupendously Large” Black Holes — A Mini, Galaxy-sized Big Bang
In 2020, a team of scientists, led by Emeritus Professor of Mathematics and Astronomy at Queen Mary University, London, Bernard Carr and Florian Kuhnel , who holds the Chair on Cosmology at the Arnold Sommerfeld Center for Theoretical Physics proposed that the behemoths lurking at the centers of galaxies could reach “stupendously large” sizes–where they would be like a mini, galaxy-sized Big Bang.”
One of the largest known black hole in the observable universe is powering the quasar TON 618 with a mass of 66 billion solar masses, leading to conjectures that even larger objects exist either within or beyond the observable universe, and to question if there is any upper limit to their sizes.
An international team of astronomers, led by Francesco de Gasperin (formerly with Leiden University, now University of Hamburg), announced the completion of a map of the sky–that to an untrained eye, appears to contain thousands of stars, but they are actually supermassive black holes–showing over 25,000 of these monster objects, each located in a different, distant galaxy.
The map, to be published in the journal Astronomy & Astrophysics, is the most detailed celestial map in the field of so-called low radio frequencies. The astronomers, including Leiden astronomers, used 52 stations with LOFAR antennas spread across nine European countries.
“This is the result of many years of work on incredibly difficult data. We had to invent new methods to convert the radio signals into images of the sky,” said de Gasperin of the effort created by combining 256 hours of observations of the northern sky. The researchers deployed supercomputers with new algorithms that correct the effect of the Earth’s ionosphere every four seconds.
“It’s similar to when you try to see the world while immersed in a swimming pool. When you look up, the waves on the water of the pool deflect the light rays and distort the view,” explained co-author Reinout van Weeren at Leiden Observatory about observations at long radio wave lengths, which are complicated by the ionosphere that surrounds the Earth. This layer of free electrons acts like a cloudy lens that constantly moves across the radio telescope.
The map now covers 4 percent of the northern half of the sky. The astronomers plan to continue until they have mapped the entire northern sky. In addition to supermassive black holes, the map also provides insight into the large-scale structure of the universe.
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