NASA Discovers Energy Knots Moving at Different Speeds in the Black Hole of Centaurus A Galaxy
The bright “knots” within the jet stream emitted from a nearby black hole appear to move at different speeds across various wavelengths. Photo: D. Bogensberger and Astrophys. J. (2024)
Analysis of X-ray data from the NASA Chandra Telescope has revealed unusual bright energy knots within the energy stream emitted from the black hole of the Centaurus A galaxy, located approximately 12 million light-years from Earth. Notably, these “knots” move faster when observed in X-rays compared to radio waves.
David Bogensberger, an astrophysicist at the University of Michigan and the lead author of the study published in The Astrophysical Journal on October 18, stated: “The X-ray data provides a unique picture that we cannot see at any other wavelength.”
This research comes amid NASA’s ongoing delay in making a final decision regarding budget cuts that will determine the fate of the Chandra Observatory and the X-ray research community.
According to SpaceNews, NASA is still operating based on its 2024 budget, even though the new fiscal year began on October 1, partly due to the 2025 budget relying on the outcome of the upcoming U.S. presidential election. Meanwhile, astronomers continue to emphasize the scientific value that the Chandra telescope has provided over its 25 years of operation.
Bogensberger’s research team analyzed two decades of Chandra observations of the supermassive black hole at the center of Centaurus A. At least one of the newly discovered “knots” appears to be moving at 94% the speed of light, surpassing the 80% speed recorded in radio wave observations.
Bogensberger added: “This means that the X-ray knots and radio waves are moving differently. There is still much we do not truly understand about how energy streams operate in the X-ray spectrum.”
Scientists are exploring ways to harness energy from black holes. (Video: Hashem Al-Ghaili)
The Centaurus A Galaxy was discovered in the mid-1800s, but it wasn’t until a century later that its twin energy jets were observed using radio telescopes. One jet points toward the northeast of Earth, while the other, known as the counter-jet, points southwest and is significantly dimmer.
Astronomers know that the energy jets of black holes are powered by matter being pulled into the black hole and ejected before it can reach the event horizon. However, the exact mechanism of how matter is incorporated into the energy jets remains unclear. The prevailing theory suggests that the strong and chaotic magnetic fields surrounding the black hole, along with its rotation, may be crucial factors.
In addition to how the knots are formed, researchers are also puzzled by the brightness variations of these knots. Over two decades, from 2002 to 2022, one knot became brighter while another faded. In 2009, astronomers observed a similar trend in the energy knots emitted from the black hole at the center of the M87 galaxy, which is about 55 million light-years from Earth. For reasons still unclear, these knots brightened over a few years to the point where they outshone the galaxy’s core before fading into space.
Further studies of the energy jets from Centaurus A and other galaxies may reveal whether the differing speeds and brightness of the knots are intrinsic behaviors of the energy streams emitted from the black hole or due to external obstacles, such as interstellar material.
