Researchers looking at the center of the Milky Way with one of the largest arrays of radio telescopes in the world have discovered thousands of mysterious strand-like structures never seen before.
These structures, known as radio filaments, jut out from the galactic center in long, thin tendrils – some of which extend up to 150 Light years long, nearly 40 times the distance between Earth and the nearest neighboring star system, Proxima Centauri.
Some filaments come in pairs, others in equidistant sets like the strings of a harp. All are bristling with energy, likely generated by billions of electrons bouncing through a magnetic field at near-lightspeed, according to two upcoming studies accepted for The Astrophysical Journal and Letters from the Astrophysical Journal.
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While scientists have known that filaments have existed around the galactic center for several decades, this new set of high-definition observations from the MeerKAT radio telescope in South Africa reveals that there are 10 times more spindly structures than previously thought. previously. Studying the mysterious bulk structures could help researchers finally understand what these filaments are and how they were created.
“Just looking at a few filaments makes it difficult to draw a real conclusion about what they are and where they came from,” said the study’s lead author, Farhad Yusef-Zadeh, professor of physics and in astronomy at Northwestern University in Evanston, Illinois. said in a press release. “Now we finally have the big picture – a panoramic view filled with an abundance of filaments… This is a turning point in deepening our understanding of these structures.”
Intergalactic energy balls
The center of the Milky Way is full of mysterious objects that are too obscured by gas and dust to be properly studied with visible light wavelengths. But focusing on the energetics radio waves radiating from the galactic center, astronomers can get a glimpse of some of the powerful structures and interactions taking place there.
Using the MeerKAT radio telescope – an array of 64 antennas in South Africa’s Northern Cape province – the authors of the new studies observed radio activity from the galactic center for 200 hours, spread over three years. From these observations, the researchers pieced together a mosaic of 20 separate observations, each focusing on a different section of the radio sky.
The resulting panorama captures many known sources of radio waves – such as bright supernova remnants and the gaseous regions of space where new stars sparkle to life – as well as the mysterious fingerprints of nearly 1,000 radio wires.
What are these finger-like structures, exactly? According to Yusef-Zadeh, the best working hypothesis is that the filaments are generated by cosmic rays — high-energy particles accelerated through space at nearly the speed of light — moving through a magnetic field. Previous studies have shown that something lurking at the center of the Milky Way acts like a gigantic particle accelerator, constantly shooting cosmic rays out into space – though the source of those rays remains a mystery.
A clue could be the huge pair of radio bubbles blowing from the galactic center, one rising just above the galactic plane and the other dipping below. Discovered in a previous MeerKAT survey, each bubble of radio energy peaks about 25,000 light-years high (about a quarter of the width of the Milky Way itself), and was likely produced by an ancient explosion from the center. of the galaxy. black hole.
According to the authors of the new studies, many newly detected radio filaments fall into the cavities of these huge bubbles. It’s possible that the strand-like filaments were created by the same ancient burst of black hole activity that blew up the radio bubbles millions of years ago. However, even this explanation leaves big questions unanswered.
“We still don’t know why they come in clusters or understand how [the filaments] separated, and we don’t know how these regular spacings occur,” Yusef-Zadeh said. “Every time we answer a question, several other questions arise.
Future radio surveys of the area will focus on how the filaments move or change position over time, the researchers said.
Originally posted on Live Science.