Data from the Event Horizon Telescope reveals a glimpse of the supermassive black hole at the center of the Centaurus A galaxy.
Astronomers from the Max Planck Institute in Germany (the team that released the first image of a black hole in 2019) have recently directed the Event Horizon Telescope (EHT) towards a massive jet of plasma emitted by the central black hole of the Centaurus A radio galaxy, located about 13 million light-years from Earth in the constellation Centaurus. The data reveals that these jets are brighter at the edges compared to the center, a phenomenon also observed in other black holes, but never so clearly.
The observations align with what has formed the basis of Albert Einstein’s general theory of relativity, and the researchers believe that the largest supermassive black holes are “magnified versions” of smaller black holes; in other words, they operate similarly.
The supermassive black hole at the center of the Centaurus A galaxy has a mass 55 million times that of the Sun, significantly larger than Sagittarius A*, the black hole at the center of our Milky Way (which has a mass 4 million times that of the Sun), but still much smaller than the object at the center of Messier 87 galaxy (which has a mass 6.5 billion times that of the Sun).
All of these black holes have been extensively studied, partly because their jets can be observed in X-rays and radio wavelengths. Compared to previous high-resolution observations, the new EHT images were captured at a frequency 10 times higher and are 16 times sharper.
Jet of plasma emitted from the black hole at the center of the Centaurus A galaxy. (Image: EHT/NASA).
The EHT is not a single instrument but a network of radio telescopes located around the globe. Their resolution is so high that they can accurately pinpoint the origin of the jet: from the very center of the black hole, the research team emphasizes.
Supermassive black holes at the centers of galaxies like Centaurus A are “devouring” gas, dust, and surrounding material due to their enormous gravitational pull. This process releases a tremendous amount of energy and makes the galaxy more “active.”
Most of the material near the edge of the black hole is pulled inward. However, some particles around are blown out into space at speeds close to the speed of light. It is these “escaping” particles that form the plasma jet, one of the most mysterious and powerful phenomena in the galaxy.
Astronomers still do not fully understand how the jets are emitted from the black hole’s center, nor how they can expand to sizes larger than the host galaxy without dispersing.
Based on the new discoveries from the EHT regarding the jets, the research team hopes that future observations at shorter wavelengths and higher resolutions may directly image the central black hole of the Centaurus A galaxy.
The details of the study were published in the journal Nature Astronomy on July 19.
