A giant galaxy 3.3 million light-years across has been found by astronomers using … [+]
A giant galaxy 3.3 million light-years across has been found by astronomers using an array of radio telescopes in South Africa.
One of the largest galaxies ever found, the giant is about 1.44 billion light-years away and is estimated to be 32 times the size of our own Milky Way galaxy.
Meet ‘Inkhatoho’
The powerful object is classified as a giant radio galaxy, whose structures are jets of hot plasma that scatter millions of light years across intergalactic space. Scientists think jets are powered by supermassive black holes in the centers of galaxies.
It has been dubbed “Inkhatoho” – meaning trouble in the African languages Xhosa and Zulu – by scientists in a paper published this week in Monthly Notices of the Royal Astronomical Society.(although its catalog name is MGTC J100022.85+031520.4).
The newly discovered giant radio galaxy ‘Inkhatoho’. Glowing plasma jets, as seen by MeerKAT … [+]
‘disturbing’ physics
Kathleen Charlton, a Masters student at the University of Cape Town and first author of the new study said the nickname reflects the fact that “it’s been a bit of a struggle to understand the physics behind what’s going on here”.
The giant galaxy was discovered using South Africa’s 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 shine at radio frequencies.
As radio telescopes like MeerKAT become more sensitive, more and more GRGs are being discovered. “Research on GRGs is developing so quickly that it’s becoming difficult to keep up,” Charlton said. “It’s so exciting!”
A spectral map of the age of ‘Inkathozo’. Cyan and green indicate younger plasma, while purple indicates older … [+]
Extreme science
Another of the paper’s co-authors, Dr Kshitij Thorat of the University of Pretoria, called it “exciting and unexpected”. The highest-resolution data ever of a GRG revealed a complex interplay between 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 still do not understand much of the complicated plasma physics at play in these extreme galaxies,” Thorat said.
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 of these giant megastructures. Inkathazo is the third GRG to be found in a small patch of sky no bigger than five full moons after two were discovered in 2021.
Exciting era
MeerKAT will soon be part of the Square Kilometer Array, a $2.2 billion cross-continental complex of radio telescope networks – 197 radio dishes in the Karoo in South Africa’s Northern Cape and 131,072 antennas at Murchison in outback Western Australia. Together, they will form a total collection area of one kilometer spanning two continents, which will allow the detection of very weak radio signals.
“We are 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, SKA will allow us to push these boundaries even further and hopefully solve some mysteries surrounding enigmatic objects such as giant radio galaxies.”
I wish you clear skies and open eyes.
