Noise and chaos reign at the heart of the Milky Way, our own galaxy, it seems in a stunning image taken recently by astronomers in South Africa.
The image, taken by the MeerKAT radio telescope, an array of 64 antennas spanning five miles of desert in northern South Africa, reveals a storm of activity in the central part of the Milky Way, with wires of radio emission passing through the galaxy. space are laced and buckled between bubbles of energy. At its center, Sagittarius A*, a well-studied supermassive black hole, emits its own exuberant buzz.
We are used to seeing distant galaxies as soft, glowing eggs of light or as majestic, bejeweled eddies. Rarely do we glimpse the swirling under the clouds – all forms of frenzy that can reach a hundred million stars.
The image was captured and analyzed by a team of astronomers led by Ian Heywood of the University of Oxford and the South African Radio Astronomy Observatory. They published their results last week in the Astrophysical Journal.
MeerKAT is a precursor to the Square Kilometer Array, an immense array of antennas to be built in South Africa and Australia over the next decade. When completed, it will be the most powerful radio telescope on Earth in the near future.
For visible-light telescopes, large areas of the Milky Way sky are blackened by intervening clouds of cosmic dust. But radio waves pass right through it, allowing MeerKAT to get up close and personal.
“The best telescopes broaden our horizons in unexpected ways,” Fernando Camilo, chief scientist at the South African Radio Astronomy Observatory and one of the many co-authors of the new paper, said in a press release.
Twenty separate observations, generating 70 terabytes of data and requiring three years of processing, were needed to produce the image. The result is a panorama 1000 light-years wide and 600 light-years high of the central regions of the Milky Way. (The entire galaxy is 100,000 light-years in diameter, and its center is 25,000 light-years from Earth.)
The disk of the Milky Way, where most of the stars and exoplanets are located, appears in the image as a ragged horizontal stripe. A dense blob of energy in the center of the streak marks the lurking spot of a black hole four million times the mass of our sun. The surrounding area is filled with mysterious glowing filaments as long as 100 light-years long.
Astronomers have suspected that such filaments, first recognized 35 years ago, are formed by magnetized tubes of gas and high-energy particles. But scientists still don’t understand how these came to be. The new paper, the study authors claim, collected enough new examples of such traits to study their traits and varieties as a group for the first time.
Vertically above and below the galactic disk radiate a pair of giant radio bubbles, likely the remnants of a series of supernova explosions that took place several million years ago. In the background, the radio image is speckled with the bright dots of supermassive black holes in distant galaxies.
“I spent a lot of time looking at this image while I was working on it, and I never tire of it,” said Dr. heyman.
dr. Camilo agreed that the bowels of the galaxy resembled an electrical storm. “Electrical activity is, of course, critical to our living animal hearts,” he added. “I suppose you could say that without electrical activity the center/heart of the galaxy, if not dead, would look very, very different.”
