A discovery in the heart of the Milky Way surprises a researcher who has been working on the subject for decades.
CHICAGO – The Milky Way is the galaxy we live in – and yet it never ceases to amaze researchers. Just recently, a research team discovered that the galaxy may look very different from what previously thought. Now, another research group has made a new discovery in the heart of the Milky Way, where there are hundreds of filaments, one-dimensional "threads" about five to ten light-years long, aligned along the galactic plane.
Almost 40 years ago, researcher Farhad Yusuf-Zadeh discovered a similar phenomenon: long, one-dimensional "threads" located near the supermassive black hole Sagittarius A* at the center of our Milky Way. At first glance, two things distinguish the discovery from the current one: The filaments, which have been known since 1984, are significantly longer and vertically oriented at up to 150 light years, while the newly discovered "threads" are shorter and horizontally aligned. In images, they appear "like the dots and dashes of Morse code," according to a statement from Northwestern University.
Newly discovered filaments in the Milky Way point to black hole
One of the discoverers of the new film is Yusuf-Zadeh, who assumes that the "threads" have different origins. "It was a surprise to suddenly find a new population of structures that seem to be pointing in the direction of the black hole," he recalls. "I was really overwhelmed when I saw her. We had to do a lot of work to make sure that we weren't fooling ourselves," says the researcher. The study was published in the Astrophysical Journal Letters.
A research team has discovered hundreds of radio filaments in the heart of the Milky Way. The long and vertical threads have been known for decades, the short ones have only just been discovered. © Farhad Yusef-Zadeh/ Northwestern University
Yusuf-Zadeh's team found that the threads are not random, but apparently related to the outflow of our black hole. "It's satisfying to find order in the middle of a chaotic field of the core of our galaxy," Yusuf-Zadeh points out. The radio astronomy expert is convinced that the new discovery has a lot to do with further developments in radio astronomy – especially with the MeerKAT telescope, which connects 64 radio antennas in South Africa. "The new MeerKAT observations were revolutionary," he emphasizes. "The advancement of technology and the time we spend observing have provided us with new information. This is really a technical achievement of the radio astronomers."
Discoverer of the filaments at the centre of the Milky Way is shocked
Yusuf-Zadeh has been studying vertical filaments in the center of the Milky Way for decades – now he is downright shocked that there are also horizontal filaments, according to his university's statement. "We have always thought about the vertical filaments and their origin. I am used to the fact that they are vertical and have never suspected that there could be others along the plane," the astronomer is quoted as saying.
A closer look at the newly discovered filaments, Yusuf-Zadeh's research group discovered even more differences to the filaments that have been known for decades: The vertical "threads" are magnetic, the horizontal filaments seem to emit thermal radiation. While the vertical filaments contain particles that move at almost the speed of light, the horizontal filaments seem to accelerate thermal material in a molecular cloud. While several hundred vertical "threads" have been discovered, there are only a few hundred horizontal filaments that appear to be located on only one side of the black hole and point in its direction.
"Threads" discovered in the center of the Milky Way
The study of the newly discovered "threads" at the center of the Milky Way has only just begun, but the research team is already reporting initial findings: "One of the most important implications of the radial outflow we discovered is the orientation of the accretion disk and the jet-driven outflow of Sagittarius A* along the galactic plane," says Yusef-Zadeh. " We believe that they must have arisen through some kind of outflow from an activity that took place a few million years ago," explains the researcher. "It appears to be the result of an interaction of this outflowing material with objects in its vicinity." (tab)