Black holes are some of the most enigmatic celestial objects in the Universe, as researchers have always been bewildered at how these bodies came to be. One particular structure black holes were noticed to have, was creating X-shaped galaxies, and now scientists have discovered the mechanism behind this behavior.
The Largest X-Shaped Radio Galaxy Discovered
One such example is the galaxy PKS 2014-55, which is located about 800 million light-years away from Earth. The researchers have published highly detailed images of the PKS 2014-55 galaxy, which is also the largest X-shaped ‘radio galaxy’ ever discovered.
The notable shape of PKS 2014-55 is made up of two pairs of giant lobes that carry hot jets of electrons that flow outwards from a supermassive black hole at the galaxy’s center. Usually, radio galaxies have one pair of lobes, but PKS 2014-55 is different: one of the pairs of lobs is the ‘jet’ and the other the ‘counter-jet’ in this case.
Centaurus A, seen below, is an instance of a giant elliptical galaxy with two prominent radio lobes.
There have been a few hypotheses as to how the galaxy came to be. The first theory suggested that the jets change its direction throughout the course of millions of years because of the spinning black holes. The second hypothesis is that the radio waves are comprised of stellar material that falls forwards the black holes but eventually heads towards different directions.
Upon observing PKS 2014-55, the team found that the galaxy is most likely explained by the second theory as it ejected stellar material that ended up charging its direction. This resulted in the material going back to its host galaxy through the ‘counter-jet’ lobs.