A galaxy has mysteriously redirected a powerful jet of radiation at Earth.
Research has revealed that galaxy, named PBC J2333.9-2343, has changed the direction of the jet "drastically by an angle of up to 90 degrees".
A study by a team of international astronomers explains the jet is observed "going from being in the plane of the sky, perpendicular to our line of sight, to pointing directly towards us."
The event marks the first observation of a reorientation so dramatic that it changes the category a galaxy fits into.
The galaxy was previously classified as a radio galaxy, but the new research has revealed it has now been classified as a giant radio galaxy that is 4 million light years across and happens to have a blazar in its core.
A blazar is an active galactic nucleus (AGN) with a relativistic jet (a jet travelling close to the speed of light) directed towards an observer.
Blazars are very high energy objects and are considered to be one of the most powerful phenomena in the Universe.
The galaxy is located 656,844,372 light years away, with a light year being equivalent to about 9.46 trillion kilometres, or 5.88 trillion miles.
The Royal Astronomical Society explain: "A blazar jet is made of elemental charged particles like electrons or protons that move at velocities close to the speed of light.
"These move in circles around a strong magnetic field, causing the emission of radiation across the entire electromagnetic spectrum.
"In PBC J2333.9-2343, the jet is thought to originate from or close to the supermassive black hole in its centre.
"With the jet pointing in our direction, the emission is strongly enhanced and can easily exceed that coming from the rest of the galaxy.
"This in turn drives high-intensity flares stronger than those coming from other radio galaxies, thus changing its categorisation."
The team do not yet know what caused the drastic change in direction of the jets. They speculate that it could have been a merging event with another galaxy or any other relatively large object, or a strong burst of activity in the galactic nucleus after a dormant period.
Dr Lorena Hernández-García, lead author of the paper and researcher at the Millenium Institute of Astrophysics, says "We started to study this galaxy as it showed peculiar properties. Our hypothesis was that the relativistic jet of its supermassive black hole had changed its direction, and to confirm that idea we had to carry out a lot of observations.
"The fact that we see the nucleus is not feeding the lobes anymore means that they are very old. They are the relics of past activity, whereas the structures located closer to the nucleus represent younger and active jets."
To study the unusual galaxy, astronomers observed it across a wide range of the electromagnetic spectrum. Data was obtained from the German 100m-Radio Telescope Effelsberg at the Max Planck Institute for Radio Astronomy, the Yale University 1.3m-SMARTS optical telescope, and the Penn State Neil Gehrels Swift Observatory.
The team then compared the properties of PBC J2333.9-2343 with large samples of blazars and non-blazar galaxies provided by the ALeRCE (Automatic Learning for the Rapid Classification of Events) project in Chile with data from the Zwicky Transient Facility (ZTF) and the Asteroid Terrestrial-impact Last Alert System (ATLAS).
The work is published in Monthly Notices of the Royal Astronomical Society.
