The mystery of a strange X-Galaxy powered by a Black Hole monster is finally solved

A team of American and South African researchers has published Highly detailed images of the largest X-shaped "radiogalaxy" ever discovered: PKS 2014-55.

In particular, they have helped to resolve the current confusion about the unusual shape of the galaxy.

The spectacular new images were taken using antenna 64 MeerKAT telescope in South Africa, by an international research team led by Bill Cotton of the National Radio Astronomy Observatory in the United States. USA

(Courtesy of SARAO and Bill Cotton et al / Author provided (no reuse))

Sure: The MeerKAT image of the giant X-shaped radio galaxy PKS 2014-55.

Approaching a cosmic giant

Our research team also took detailed photos of the PKS 2014-55 galaxy last year, as part of the Evolutionary map of the Univers project led by an astrophysicist Ray norris. We use CSIRO Australia square kilometer matrix pathfinder (ASKAP) telescope in Western Australia, which has just completed its first series of astronomical pilot studies.

Thanks to its innovative "radio cameras", ASKAP can quickly map very large areas of the sky to catalog millions of objects emitting radio waves, remnants of supernovae close to distant galaxies.

(CSIRO and EMU / Author kit provided (no reuse))

Sure: Our ASKAP image of the giant X-shaped radio galaxy PKS 2014-55.

The prominent X shape of the PKS 2014-55 is made up of two pairs of giant lobes composed of jets of hot electrons. These jets come out of a a supermassive black hole in the heart of the galaxy

The lobes emit electromagnetic radiation in the form of radio waves, which can only be detected with radio telescopes such as REQUEST. Humans cannot see radio waves. But if we could, the Earth PKS 2014-55 would be roughly the same size as the Moon.

What does a galaxy radio do?

Typically, radio galaxies only have one pair of lobes. One is a "jet" and the other is a "jet jet".

These jets develop in the surrounding space at almost the speed of light. At first, they move in a straight line, but they twist and fold in many wonderful ways when they meet their surroundings.

Centaur A, seen below, is an example of a giant elliptical galaxy with two prominent radio lobes.

(NASA Goddard Space Flight Center / Flickr, CC BY 4.0)

Sure: This image of the Centaurus A galaxy incorporates radio and optical data. Each galaxy has a dungeon at its center, including the Milky Way.

Galaxy PKS 2014-55 giant x shape, with two pairs of lobes emerging at very different angles, is very unusual.

What do the lobes do?

To understand why having two pairs of lobes is unusual, we must first understand what creates the lobes.

Almost all large galaxies have a supermassive black hole in their center.

In an active galaxy, powerful jets of charged particles can exit the area around the supermassive black hole. Astronomers think they are emitted near the poles of the black hole, so there are two, and they usually point in opposite directions.

When the activity of the black hole stops, the jets stop growing and the material therein flows towards the center. Therefore, what we see as a lobe of a radio galaxy is made up of both a jet stream and reflux material.

A mystery solved

In the past, there were two main theories as to why PKS 2014-55 had two pairs of lobes.

The former suggested that there was in fact of them massive active black holes in the center of the galaxy, each emitting two powerful jets.

The second theory suggested that the supermassive black hole had undergone a twist twist. It is when the axis of rotation of a rotating black hole has a sudden change in orientation, resulting in a second pair of jets at a different angle from the first pair.

But recent observations from the South African MeerKAT telescope strongly suggest a third possibility: that the two largest lobes are the rapidly moving particles moving away from the black hole, while the two smaller lobes are looping towards the Rear to reverse.

The MeerKAT team produced high resolution images ten times more sensitive than our ASKAP pilot observations made here in Australia last year.

A cosmic wonder

Using CSIRO ASKAP Telescope, our team observed that the "purple butterfly" PKS 2014-55 is a huge cosmic structure. It spans at least five million light years, about 20 times the size of our own galaxy, the Milky Way.

PKS 2014-55 is located on the outskirts of a massive group of galaxies known as Abell 3667. It was discovered over 60 years ago Cross Mills Telescope in the old man of CSIRO Flower station in New South Wales

The first detailed radio image of the galaxy was taken by Ron Ekers in 1969

REQUEST

The ASKAP telescope that we used to capture the PKS 2014-55 is a set of 36 radio antennas distributed in a pattern of six kilometers in diameter. Together, the dishes form a large radio telescope that uses the rotation of the Earth to produce sharp images from near and far astronomical sources.

Each plate is 12 meters wide and team thanks to new technologies developed by CSIRO and its industrial partners. ASKAP is a rapid survey machine, which takes radio images over very large areas of the sky. Several sky-wide surveys are expected to begin next year.