![]() In other words, the Centaurus A black hole doesn't seem to behave differently from its bigger or smaller siblings, adding further credence to physicists' notion that these exotic objects can be defined just by their mass, charge, and spin. The jets emitted by Centaurus A's black hole look pretty much the same as the EHT's images of M87, just on a smaller scale. That falls smack in the middle between M87 (6.5 billion solar masses) and the mass of the black hole at the center of our own Milky Way galaxy (about 4 million solar masses). The new Centaurus A observations are also of interest because the black hole at its center is medium-sized: 55 million times the mass of our Sun. "It's a striking feature that will help us better understand jets produced by black holes." "Now we are able to rule out theoretical jet models that are unable to reproduce this edge-brightening," said co-author Matthias Kadler of the University of Würzburg in Germany. But only the outer edges of the jets emit radiation, perhaps due to the jets colliding with galactic gas, thus heating the edge. According to this latest EHT data, the radio emissions form massive lobes emanating outward from Centaurus A. The new images of Centaurus A place even more constraints around the various competing theories, further narrowing the possibilities. The EHT is created by interferometry, which uses light captured at different locations to build an image with a resolution similar to that of a telescope the size of the most distant locations. Interferometry has been used for facilities like ALMA (the Atacama Large Millimeter/submillimeter Array), where telescopes can be spread across 16 km of desert. Instead, it's a collection of telescopes scattered around the globe. Centaurus A has been studied extensively ever since in the radio, optical, X-ray, and gamma-ray regimes.Īs Ars' John Timmer reported back in 2019, the EHT isn't a telescope in the traditional sense. That's because the galaxy boasts an active galactic nucleus, which produces powerful jets that emit light in both X-ray and radio wavelengths that span distances far greater than the size of the galaxy itself. In 1949, astronomers identified Centaurus A as the first known source of radio waves outside the Milky Way galaxy. In 1847, John Herschel noted its peculiar shape-it looks elliptical when viewed from Earth, with a lane of dust superimposed across it.ĮSO/WFI MPIfR/ESO/APEX A. Located in the constellation Centaurus, the galaxy was discovered in 1826 by James Dunlop. "We see up close and personally how a monstrously gigantic jet launched by a supermassive black hole is being born."Ĭentaurus A (aka NGC 5128) is one of the largest and brightest objects in the night sky, making it especially popular with amateur stargazers, although it's only visible from the Southern Hemisphere and low northern latitudes. "This allows us for the first time to see and study an extragalactic radio jet on scales smaller than the distance light travels in one day," said co-author Michael Janssen, an astronomer at Max Planck Institute for Radio Astronomy in Bonn and Radboud University Nijmegen. The jet's unusual characteristics could help astronomers answer a few nagging questions about how such jets are produced in the first place. The images also capture the birth of a powerful jet emitting from the black hole. The images enable the EHT to pinpoint the location of the supermassive black hole at the galaxy's center, according to a new paper published in the journal Nature Astronomy. Now, the EHT is back with another exciting breakthrough: images of the "dark heart" of a radio galaxy known as Centaurus A. The Event Horizon Telescope (EHT) collaboration made headlines in 2019 by capturing the very first direct image of a black hole at the center of a galaxy.
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