A giant galaxy measuring 3.3 million light-years across has been found by astronomers using a radio telescope array in South Africa.
One of the largest galaxies ever found, the behemoth is about 1.44 billion light-years away and reckoned to be 32 times the size of our Milky Way galaxy.
Meet ‘Inkathazo’
The mightly object is classed as a giant radio galaxy, whose signature structures are jets of hot plasma being spewed millions of light-years across intergalactic space. Scientists think the jets are powered by supermassive black holes at the centers of galaxies.
It’s been nicknamed “Inkathazo”—meaning trouble in the African Xhosa and Zulu languages—by scientists in a paper published this week in the Monthly Notices of the Royal Astronomical Society.(though its catalog name is MGTC J100022.85+031520.4).
‘Troublesome’ Physics
Kathleen Charlton, a Master’s student at the University of Cape Town and the first author of the new study said the nickname reflects the fact it’s, “been a bit troublesome to understand the physics behind what’s going on here.”
The giant galaxy was discovered using the South African MeerKAT radio telescope, an array of 64 antennas in the Meerkat National Park in the country’s Northern Cape. Only radio telescopes can locate GRGs, which glow at radio frequencies.
As radio telescopes like MeerKAT get more sensitive, more and more GRGs are being discovered. “Research into GRGs is developing so rapidly that it’s becoming hard to keep up,” said Charlton. “It’s incredibly exciting!”
Extreme Science
Another of the paper’s co-authors, Dr Kshitij Thorat from the University of Pretoria, called it “exciting and unexpected.” The highest-resolution data ever of a GRG revealed a complex interplay between the plasma jets and hot gas in the voids between galaxies in a cluster that is beyond current knowledge. “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,” said Thorat.
Although most GRGs have been found in the northern sky by radio telescopes north of the equator, the relatively less explored southern sky is proving a treasure trove for these giant megastructures. Inkathazo is the third GRG to be found in a small patch of sky no larger than five full moons after two were discovered in 2021.
Exciting Era
MeerKAT will soon form part of the Square Kilometre Array, a $2.2 billion cross-continental complex of radio telescope networks—197 radio dishes in Karoo in South Africa’s Northern Cape and 131,072 antennas in Murchison in the outback of Western Australia. Together, they will form a total collecting area of one kilometer spanning two continents, which will allow the detection of very faint radio signals.
“We’re entering an exciting era of radio astronomy,” said Dr. Jacinta Delhaize, a researcher at the University of Cape Town who led the 2021 discovery. “While MeerKAT has taken us further than ever before, the SKA will allow us to push these boundaries even further and hopefully solve some of the mysteries surrounding enigmatic objects like giant radio galaxies.”
Wishing you clear skies and wide eyes.
