It was a different kind of X-Files mystery. Astronomers had been puzzling over some galaxies that spew out X-shaped jets of radio waves from the black holes that lurk at their centers.
Galaxies with twin jets shooting off in opposite directions are common, but the cause of the elaborate X-jets was uncertain until the MeerKAT telescope in South Africa took a close look at one of these odd cosmic formations.
MeerKat's radio-wave observations of "X-galaxy" PKS 2014-55 have revealed a boomerang-like structure of "material falling back into the galaxy being deflected into different directions forming the other two arms of the X."
A team led by scientists from the South African Radio Astronomy Observatory (SARAO), which operates MeerKAT, will publish their findings in the Monthly Notices of the Royal Astronomical Society journal.
SARAO released a graphic highlighting the pattern of the jets.
Astronomers had considered that X-galaxies might be created by changes in a black hole's spin direction or by two black holes working as a team. MeerKAT's clear view of PKS 2014-55, however, supports the double-boomerang model.
The jets of radio waves are truly epic. They stretch for millions of light-years into space. "Eventually, they are 'turned back' by the pressure of tenuous intergalactic gas. As they flow back towards the central galaxy, they are deflected by its relatively high gas pressure into the shorter, horizontal, arms of the boomerang," said SARAO.
MeerKAT was officially inaugurated in 2018, but has already spottedand delivered a .
"MeerKAT was designed to be the best of its kind in the world." said study co-author Bernie Fanaroff. "It's wonderful to see how its unique capabilities are contributing to resolving longstanding questions related to the evolution of galaxies."