Event Horizon: The team of astronomers who two years ago captured the first close-up of a giant black hole, located in the center of galaxy Messier 87 (M87), has just zoomed in on a second giant a little smaller in the next active galaxy, Centaurus A The feat, documented in the scientific journal Nature Astronomy, was carried out by the team at the Max Planck Institute for Radio Astronomy in Bonn, Germany.
The image, captured by the Event Horizon Telescope (EHT), should help resolve questions about how these galactic centers channel large amounts of matter into powerful beams and fire them thousands of light-years into space.
Together, the images support the theorists’ belief that all black holes operate in the same way, despite huge variations in their masses. “This is very good,” said astronomer Philip Best of the University of Edinburgh of the EHT’s new image. “The angular resolution is amazing compared to previous images of these jets,” said Best.
How the Event Horizon Telescope works
The EHT combines dozens of radio antennas scattered from Hawaii to France and from Greenland to the South Pole — forming a massive virtual telescope. He simultaneously points the antennas at a celestial object, carefully keeping time with an atomic clock. The researchers then merge the images into computing clusters — in a process that takes years — to produce a single image with resolution as sharp as that of a single Earth-sized antenna.
The EHT only operates for a few weeks each year and bad weather and technical failures often narrow the operating window even further. The virtual telescope probed Centaurus A in 2017 and produced the now famous image of the supermassive black hole in M87 — the scientific discovery of the year 2019.
Centaurus A, about 13 million light years away, is one of the closest galaxies to Earth that glows at radio wavelengths. It has obvious jets spewing matter above and below the galactic disk — a hallmark of an active giant black hole. “We wanted to see what the jet would look like with the resolution that EHT could offer,” said Michael Janssen, one of the team members. “We didn’t know what to expect,” added the scientist.
The result was a detailed image of how the jet emerges from the region around Centaurus A’s supermassive black hole, showing a striking resemblance to the EHT images of the M87 jet — on a much smaller scale. While images of the Centaurus A jets taken by other telescopes at different wavelengths revealed little detail, the EHT images show the jet with a dark center flanked by two bright streaks.