Astronomers Discover Giant Radio Galaxy with Plasma Jets 32 Times the Size of the Milky Way

• Ene 21, 2025 - 22:11

Astronomers have identified a new giant radio galaxy with plasma jets that stretch 32 times the size of our Milky Way. Spanning 3.3 million light-years from end to end, this colossal structure was detected by South Africa’s MeerKAT telescope and has been named Inkathazo, meaning "trouble" in Xhosa and Zulu. The name reflects the challenge in understanding the physics behind the galaxy's behavior.

The discovery, published in Monthly Notices of the Royal Astronomical Society, has excited researchers who hope it will provide new insights into the origin and evolution of some of the largest structures in the universe.

Giant radio galaxies (GRGs) are massive entities emitting jets of hot plasma that extend millions of light-years across space. These jets, glowing at radio frequencies, are powered by supermassive black holes at the centers of galaxies.

Although previously believed to be rare, GRGs have been discovered in increasing numbers thanks to advanced radio telescopes like MeerKAT. Kathleen Charlton, a Master's student at the University of Cape Town and the first author of the study, remarked, "The number of GRG discoveries has absolutely exploded in the past five years thanks to powerful new telescopes like MeerKAT."

Charlton explained that Inkathazo was nicknamed “trouble” because its plasma jets do not exhibit the typical characteristics seen in other GRGs. Notably, one of the jets is bent rather than extending straight across, and the galaxy resides at the center of a galaxy cluster, a location where the jets’ size and development would normally be constrained.

Dr. Kshitij Thorat, a co-author of the study from the University of Pretoria, emphasized the significance of finding a GRG within a galaxy cluster, stating, "Finding a GRG in a cluster environment raises questions about the role of environmental interactions in the formation and evolution of these giant galaxies."

The researchers utilized MeerKAT’s advanced capabilities to create high-resolution spectral age maps of Inkathazo, offering a closer look at the plasma's age across different sections of the galaxy. These maps revealed unexpected energy boosts in some electrons, which may result from the jets colliding with hot gas in the space between galaxies.

"This discovery has given us a unique opportunity to study GRG physics in extraordinary detail," said Thorat. "The findings challenge existing models and suggest that we don’t yet understand much of the complicated plasma physics at play in these extreme galaxies."

While most GRGs have been discovered in the northern sky, Inkathazo is the third GRG found in a small region of the southern sky known as “COSMOS,” an area that spans roughly the size of five full moons. Previous observations by the international MIGHTEE collaboration in 2021 also identified two other GRGs in this region using the MeerKAT telescope.

"The fact that we unveiled three GRGs by pointing MeerKAT at a single patch of sky goes to show that there is likely a huge treasure trove of undiscovered GRGs in the southern sky," said Dr. Jacinta Delhaize, a researcher at the University of Cape Town who led the 2021 publication.

MeerKAT's location and power make it an ideal tool for further discoveries in this unexplored portion of the sky.

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