An Image of the MeerKAT Telescope Demonstrates the Formation of X Galaxies

Scientists from the South African Radio Astronomical Observatory had the chance to take a closer look at the X galaxies with the MeerKAT telescope. The researchers have revealed some mysteries about the formation of X-shaped galaxies with their findings.

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Tau.Neutrino said:

An Image of the MeerKAT Telescope Demonstrates the Formation of X Galaxies

Scientists from the South African Radio Astronomical Observatory had the chance to take a closer look at the X galaxies with the MeerKAT telescope. The researchers have revealed some mysteries about the formation of X-shaped galaxies with their findings.

more…

Startling image. Is this real or an artist’s impression?

> These X-shaped galaxies generally have four jets that radiate radio waves in opposite directions.

News to me. My immediate guess would be two central quasars, with rotation axes in different directions. But …

> Astronomers initially thought that X galaxies could be created by changes in the direction of rotation of a black hole or by two black holes working together. However, MeerKAT’s new findings about PKS 2014-55 support the double boomerang model. The jets of radio waves spread into space over millions of light years. Finally, they are rejected by the pressure of the intergalactic gas cycle. As radio jets propagate back to the center of the galaxy, they are deflected to create shorter, horizontal arms of the boomerang with high gas pressure.

I wouldn’t have guessed that, no way. Radio lobes created by infalling matter being redirected outwards. It doesn’t seem possible. How can they be sure?

Original press release https://www.sarao.ac.za/media-releases/south-africas-meerkat-solves-mystery-of-x-galaxies/

mollwollfumble said:

Tau.Neutrino said:

An Image of the MeerKAT Telescope Demonstrates the Formation of X Galaxies

Scientists from the South African Radio Astronomical Observatory had the chance to take a closer look at the X galaxies with the MeerKAT telescope. The researchers have revealed some mysteries about the formation of X-shaped galaxies with their findings.

more…

Startling image. Is this real or an artist’s impression?

> These X-shaped galaxies generally have four jets that radiate radio waves in opposite directions.

News to me. My immediate guess would be two central quasars, with rotation axes in different directions. But …

> Astronomers initially thought that X galaxies could be created by changes in the direction of rotation of a black hole or by two black holes working together. However, MeerKAT’s new findings about PKS 2014-55 support the double boomerang model. The jets of radio waves spread into space over millions of light years. Finally, they are rejected by the pressure of the intergalactic gas cycle. As radio jets propagate back to the center of the galaxy, they are deflected to create shorter, horizontal arms of the boomerang with high gas pressure.

I wouldn’t have guessed that, no way. Radio lobes created by infalling matter being redirected outwards. It doesn’t seem possible. How can they be sure?

Original press release https://www.sarao.ac.za/media-releases/south-africas-meerkat-solves-mystery-of-x-galaxies/

Technical article at https://arxiv.org/pdf/2005.02723.pdf

> deflected by the large and oblique hot-gas halo of the host galaxy

Still hard to believe. I’ll believe it if the have doppler velocity measurements.

> Most luminous and extended radio sources have a pair of collinear jets thought to be aligned with the spin axis of the supermassive black hole (SMBH) in the nucleus of the host galaxy. However,3–10% are X-shaped radio galaxies (XRGs) defined by having a secondset of jets or “wings” misaligned with the first. The three main models for XRGs invoke (1) a sudden or continuous reorientation of the nuclear SMBH spin axis, (2) the superposition of two independent linear jets produced by two SMBHs residing in the same host galaxy, or (3) hydrodynamical backflows from the over-pressured main jets deflected by the ellipsoidal hot interstellar medium (ISM) of the host galaxy.

> recently completed 64-element MeerKAT array of the South African Radio Astronomy Observatory (SARAO) in the Northern Cape of South Africa

> morphology, spectrum and magnetic field structure of this source

I don’t see any doppler measurements in the paper. The polarisation suggests that they’re right, but I don’t see ity as conclusive. So I’m going to file this under “possible” rather than “plausible”.

Actual image screendump from the paper.

Polarisation