SA MeerKAT Telescope solves longstanding ‘X-galaxies’ mystery

A team of astronomers from South Africa used the MeerKAT telescope to solve a longstanding puzzle in X-shaped radio galaxies.

SA MeerKAT Telescope solves longstanding ‘X-galaxies’ mystery

The X-galaxies are situated far, far away – approximately 800 million light-years from Earth; the galaxies have four jets shooting off in opposite directions. The MeerKAT telescope in SA took a closer, clearer look.

The jets of the radio waves stretch for millions of light-years into space; truly a spectacular sight. As they flow back towards the central galaxy, the waves are deflected, and therein lies the mystery.

While “twin jet” galaxies are a common occurrence in the Milky Way, the X-formation is not. Thanks to MeerKAT telescope and the team of researchers, the phenomena can finally be explained.

MeerKAT Telescope’s discovery

Normally the jets go in opposite directions, coming from a massive black hole at the centre of the galaxy. Several possible explanations have been proposed to understand this phenomenon.

The South African Radio Astronomy Observatory (SARAO) explained in a media statement submitted on Thursday 7 May 2020 that the MeerKAT telescope in the Northern Cape finally solved the long-standing puzzle.

MeerKAT telescope
Part of the ensemble of dishes forming South Africa’s MeerKAT radio telescope is seen in Carnarvon on 16 July 2016. Photo: AFP/MUJAHID SAFODIEN

The team of astronomers at SARAO took a closer look at one such galaxy, PKS 2014-55, which revealed “a boomerang-like structure of material falling back into the galaxy being deflected into different directions”.

“[The images] show the clear ‘double boomerang’ morphology of hydrodynamical backflows from the straight main jets deflected by the large and oblique hot-gas halo of the host galaxy PGC~064440. The magnetic field orientation in PKS~2014−55 follows the flow lines from the jets through the secondary wings.”

MeerKAT research team [1]

Unprecedented image quality

It was thanks to MeerKAT’s high-quality imaging capabilities that new light was shed on the X-shaped PKS~2014−55 puzzle, as previous images were blurry and left out vital data needed to solve the mystery. As per the press release:

“Computers combined the data from these antennas into a telescope 8 km in diameter and provided images in the radio band of unprecedented quality for PKS 2014-55 which enabled solving the mystery of its shape.”

PKS2014-55 explained meerkat telescope
Annotated image showing X-shaped giant radio galaxy PKS 2014-55, observed with the South African Radio Astronomy Observatory’s MeerKAT telescope, indicating the old X-shaped radio jets, the younger jets closer to the central black hole, and the region of influence dominated by the central galaxy’s stars and gas. The curved arrows denote the direction of the backflow that forms the horizontal components of the X. Credit: UP; NRAO/AUI/NSF; SARAO; DES.

The results – thanks to the collaborative efforts of SARAO, the National Radio Astronomy Observatory (NRAO, the University of Pretoria and Rhodes University – have been accepted for publication in Monthly Notices of the Royal Astronomical Society.

MeerKAT’s time to shine

The MeerKAT radio telescope was previously known as the Karoo Array Telescope. Bernie Fanaroff, former director of the SKA South Africa project that built MeerKAT and a co-author of the study, explains:

“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.”

Lead author William Cotton of the NRAO says that “MeerKAT is one of a new generation of instruments whose power solves old puzzles even as it finds new ones – this galaxy shows features never seen before in this detail which are not fully understood.”

Back in July 2019, the MeerKAT telescope discovered vast amounts of hydrogen gas in NGC 1316, a galaxy 60 million light-years from Earth.

The NGC 1316 galaxy – abbreviated from ‘New General Catalogue of Nebulae and Clusters of Stars 1316’ – is the brightest visible-light and the most powerful radio wave-emission galaxy in Fornax constellation.

Also read – SA’s MeerKAT telescope gets R800 million boost to study formation of galaxies

[1] W. D. Cotton, K. Thorat, J. J. Condon, B . S. Frank, G . I. G. Józsa, S. V. White, R . Deane, N. Oozeer, M. Atemkeng, L. Bester, B. Fanaroff, R. S. Kupa, O. M. Smirnov, T. Mauch, V. Krishnan, F. Camilo

Source : The South African More