Sharpest image to date of mysterious radio circles unveils their link to supermassive black holes


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Revealed for the first time by the Australian ASKAP radio telescope sober 2019, ORCs for Odd Radio Circles (literally strange radio circles) quickly became objects of sober fascination. Theories about their origin range from galactic shock waves to wormhole gorges (the narrowest stage of a tunnel connecting two distinct regions of spacetime). Recently, an international team of astronomers, using the world’s most advanced radio telescopes, obtained a new detailed image providing additional information to help refine theories.

The story of these mysterious new celestial objects begins in September 2021. As they examined new data transmitted by the 36 antennas that make up the network of radio telescopes located in Western Australia ASKAP (Australian Pillow Kilometer Assortment Pathfinder), astronomers discover strange shapes in the sky, unlike any known object which. One of these objects appeared as a ghostly circle of radio emissions, which seemed suspended in space like a ring of smoke.

Although the sober team Ray Norris of CSIRO (Commonwealth Scientific and Industrial Analysis Company) published sober at the beginning of the year 2019 a complete study on observation sober four sober these phenomena unpublished, abbreviated ORC, they remain an enigma. Norris said of these discoveries: Fairly quickly, we realized that this was really something very different. This is some fairly new select.

Since then, researchers have been able to find and describe five different ORCs, all from similar regions in space. The strange radio circles are about 1 million sober light years in diameter. They are larger therefore than the larger spiral galaxies. Of the five ORCs checked, astronomers saw galaxies at the center of three of them, suggesting that the circles could be typed by the galactic process. What makes them all the more interesting is that they are only visible to radio telescopes. , located in South Africa, to take the clearest image to date of an ORC and thus attempt to discover the origin of these mysterious objects. Their discovery is published in the Once a month Notices of the Royal Astronomical Modern society.

A new detailed picture and three hypotheses

this day, astronomers estimate that it con the approximately 1000 ORC in space. given that they do not resemble anything known, the specialists have therefore considered phenomena that could exist but which have not yet been observed. Norris and his colleagues focused on the very top ORC discovered. The results helped determine the size and length of the ORCs. These measure el million light-years from huge, or approximately 20 times larger than the Milky Way. Curiously, they seem to be concentrated in galaxies with active supermassive black holes in the core, which could provide clues as to where they came from. Professor Norris explains in the press release: We know that ORCs are rings of weak radio emissions surrounding a galaxy with a very active black hole in the center, but we do not yet know what results in which, national insurance why they are so rare.

orc pictures askap meerkat

( gauche) La dcouverte originale d’ORC1 dans les donnes du radiotlescope ASKAP de l’quipe d’tude scientifique de la carte volutive de l’univers (EMU). ( droite) L’observation de suivi d’ORC1 avec le radiotlescope MeerKAT. EMU

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left: picture of an original discovery of ORC1 in the data of the ASKAP radio telescope under the scientific study team under an evolving map under the universe ( EMU). right: ORC1 tracking remark with the MeerKAT radiotelescope. EMU

In addition, these ORCs have a complex construction containing several inner circles. The pictures, obtained during the study, allowed the team to produce maps of the radiation polarization and the spectral index. This low polarization picture shows a magnetic field running from the low edge of the long sphere. This suggests that a huge surge in the central galaxy caused a hot blast to crash with the faint gas below the galaxy. The resulting shock wave excited the electrons in the gas afterwards, causing them to spin around the magnetic field, generating radio waves. Norris clarifies: A big surprise of the MeerKAT result is that in the ring we see several curved filaments of radio emission. We still don’t know what it is.

Nevertheless, researchers believe that a sphere is huge because it engulfed other galaxies during the explosion within a central galaxy. The observed filaments would then be trails of gas torn from the galaxies by the passing shock wave.

Because of these observations, they have retained three main hypotheses as to the origin of these ORCs. 1) They could be the remnants of a huge growing market at the center of their host galaxy, like a merging of two supermassive black holes; 2) there may be powerful jets of energetic particles escaping from the center of a galaxy; 3) finally, they could come from the residual energy of the bursts from star development.”>

meerkat orc picture.

To truly understand these strange radio circles, scientists will need access to even more sensitive radio telescopes, such as those at the future SKA (Block Kilometer Selection) observatory. This is a planetary project to be deployed by an Inter-Governmental Company which, being developed in, will be headquartered at the Radio Observatory of Jodrell Standard bank in the United Kingdom, south of Manchester. It is supported by over a dozen countries, including the UK, Australia, South Africa, Portugal, Canada, China and India.

In simple terms, the SKA is an antenna array with a total collecting area of ​​one square kilometer. When it is operational in 2019, it will be the most fantastic radio telescope in the world. It consists of two infrastructures over an unequal radio wave range. Sober South Africa, the medium frequency instrument will be composed of 200 parables. El 2nd in low frequency will consist of 131 000 antennas, located in Australia.

Professor Norris concludes: There is no doubt that the SKA telescopes, once built, will find much more ORC and can tell us more about the life cycle of galaxies. Until the SKA becomes operational, ASKAP and MeerKAT are poised to revolutionize our understanding of the Universe faster than ever . The enigma of the ORCs is therefore still not solved and the Universe is far from having revealed all its mysteries.

Supply: arXiv20702