US, WASHINGTON (ORDO NEWS) — Many galaxies, much more active than the Milky Way, have huge double jets of radio waves extending far into intergalactic space. Usually they go in opposite directions, leaving a massive black hole in the center of the galaxy. However, some of them are more complex and seem to have four jets forming an “X” in the sky.
To understand this phenomenon, several possible explanations have been proposed. These include changes in the direction of rotation of a black hole in the center of the galaxy and its associated jets over millions of years; two black holes, each of which is connected with a pair of jets; and the material falling back into the galaxy deviates in different directions, forming two other X arms.
New observations with the MeerKAT radio telescope of one of these galaxies, PKS 2014-55, strongly confirm the last explanation, since they show that the material is turning around and returning to its own galaxy. The results have just been accepted for publication in the journal The Monthly Notifications of the Royal Astronomical Society.
This work was done by a team from the South African Radio Astronomy Observatory (SARAO), the National Radio Astronomy Observatory (NRAO), the University of Pretoria and the University of Rhodes.
In previous studies of these unusual galaxies, a high-quality image obtained with the newly built MeerKAT telescope was lacking. This telescope consists of 64 radio receivers located in the Karu semi-desert in the North Cape Province of South Africa. Computers combined the data of these antennas into a telescope with a diameter of 8 km and provided images in the radio range in unprecedented quality, which allowed to solve the riddle of its shape.
Bernie Fanarov, a former director of SKA’s South African project, which created 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 nice to see how unique its capabilities are, contributing to the solution of long-standing issues related to the evolution of galaxies.
NRAO lead author William Cotton said: “MeerKAT is one of the tools of the new generation, the strength of which solves the old puzzles, even when it finds new ones, this galaxy demonstrates features that were not previously seen in all the details that are not fully understood.” Further studies of these open questions are already underway.
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