Astronomers Capture Rare Image Of Black Hole Plasma For 2nd Time
In 2019, astronomers with the Event Horizon Telescope (EHT) project made history after they imaged the shadow of a black hole for the very first time. The picture showed a dark circle surrounded by swirling, bright features resembling a ring of fire, just like Einstein’s general relativity predicted.
Now, researchers affiliated with the EHT have done it again, this time for a much smaller black hole. The findings suggest that black holes behave similarly over a wide range of masses, Tibi Puiu reported for ZME Science.
The first historic direct image of a black hole revealed the event horizon of the supermassive black hole that sits at the heart of Messier 87, a distant galaxy located about 53.5 million light-years away.
This is a huge black hole even by supermassive standards. M87’s supermassive black hole packs the mass of several billion suns into a surprisingly tiny volume. It’s about 1,000 times more massive than the Milky Way’s black hole, Sagittarius A.*
Black holes are the dark remnants of collapsed stars whose gravity is so intense that nothing, not even light, can escape. Because light cannot escape the gravitational pull of a black hole, it is virtually impossible to image or photograph one.
However, matter and energy aggregate around the edge of a black hole, a ring-shaped feature known as the event horizon — and this can be imaged because some light manages to escape and reach us.
For M87, due to its behemoth mass, the jets of matter around the event horizon came to resemble a ring of light or an accretion disk.
Now, a team of astronomers led by Michael Janssen of the Max-Planck-Institut für Radioastronomie in Bonn, Germany, has made a new radio observation of the jet of plasma emitted from another supermassive black hole.
The researchers directed the EHT —a combination of eight radio telescopes located all around the world that form a planetary-scale radio telescope — towards Centaurus A, the nearest active galaxy to Earth with a strong hot plasma jet that emits lots of radio emissions. It lies about 12 million light-years away in the southern constellation of Centaurus.
“It [Centaurus radio waves] is gigantic – 1.5 million light-years across. If you had radio eyes, you would see a structure that covers 200 times that of the full moon,” said Heino Falcke, professor of Astroparticle Physics and Radio Astronomy at Radboud University Nijmegen in the Netherlands and Janssen’s Ph.D. advisor. “With the EHT we see the innermost region of jets and we can see their structure. That is very difficult and rare,” Falcke said.
“What we found was that Cen A looks remarkably like M87. Like a giant pair of scissors- telling us that these jets are hollow. Probably due to the action of magnetic fields ejecting the plasma.”