The long-lived mystery surrounding “X”-shaped radio galaxies is no longer an enigma. The puzzle has been solved using the MeerKAT telescope, after a team of astronomers from South Africa and the US came together to study the phenomenon.
In a statement,The South African Radio Astronomy Observatory (SARAO) explained that galaxies which are more active than the Milky Way have massive “twin jets of radio waves extending far into intergalactic space”. Usually, the jets go in opposite directions emitting from a black whole in the centre of the galaxy.
Those galaxies which are more complicated seem to have 4 jets, which form an “x”. Hence, the “X”-galaxy.
Many have tried to understand why this happens, and many theories have been put forward. Some of these include: “changes in the direction of spin of the black hole at the centre of the galaxy, and associated jets, over millions of years; two black holes each associated with a pair of jets; and material falling back into the galaxy being deflected into different directions forming the other two arms of the ‘X’.”
The MeerKAT has observed the X-galaxy called PKS 2014-55. The observations lean toward confirming the last explanation mentioned above. According to SARAO’s statement, the observations made by the The MeerKAT “show material “turning the corner” as it flows back towards the host galaxy”.
A team of astronomers from South Africa and the US have used the MeerKAT telescope to solve a longstanding puzzle in ‘X’-shaped radio galaxies. Read more: https://t.co/WpDgeufryv #sarao #meerkat #xgalaxies pic.twitter.com/7yx4Xy6w7W
— SARAO (@SKA_Africa) May 7, 2020
Other studies which have attempted to answer the question of the “X”-galaxies were unsuccessful due to their lack of high quality imaging provided by the recently completed MeerKAT telescope.
Bernie Fanaroff, former director of the SKA South Africa project that built MeerKAT, and a co-author of the study, notes that “MeerKAT was designed to be the best of its kind in the world. It’s wonderful to see how its unique capabilities are contributing to resolving longstanding questions related to the evolution of galaxies.”
Image: SARAO / Media Release (Credit: NRAO/AUI/NSF; SARAO; DES.)