Finnish Astronomers Capture First Image of Orbiting Black Holes

Finnish astronomers have achieved a groundbreaking milestone by capturing the first-ever image of two black holes orbiting each other. This significant discovery offers definitive evidence that black holes can exist in pairs, as detailed in a study published on October 9, 2023, in The Astrophysical Journal.

Mauri Valtonen, an astronomer at the University of Turku, expressed excitement over this historic achievement, stating, “For the first time, we managed to get an image of two black holes circling each other.” The duo was identified through subtle variations in radio light detected by both terrestrial and space telescopes, alongside the intense particle jets they emit.

The black holes are located approximately 5 billion light-years from Earth, orbiting the core of a quasar known as OJ287. Quasars are bright galactic centers formed when massive black holes consume surrounding gas and particles. The primary black hole in OJ287 has an estimated mass of around 18 billion solar masses, while its smaller counterpart weighs nearly 150 million solar masses.

Detecting the Invisible

Despite their inherent darkness, black holes can be observed indirectly through the particle jets they emit or the glowing gas that surrounds them. Valtonen noted that OJ287 is bright enough to be seen by amateur astronomers using private telescopes. He highlighted the unique nature of OJ287, which has been suspected to host two orbiting black holes, creating a recognizable pattern of light fluctuations every 12 years.

The hypothesis regarding the presence of a second black hole was initially proposed in 1982 by Aimo Sillanpää, a student at the University of Turku, who noticed that the brightness of OJ287 varied on a decadal scale. The recent imaging serves as the first solid confirmation of this cosmic phenomenon, often referred to as a “happy hour” in astronomical terms.

To achieve this, researchers utilized a network of radio telescopes, including the Russian RadioAstron satellite, which operated from 2011 to 2019. Valtonen explained that the satellite’s radio antenna reached halfway to the Moon, significantly enhancing the resolution of the captured images compared to Earth-based telescopes.

Confirming the Twin Black Holes

By analyzing the images alongside prior theoretical predictions, scientists successfully identified two distinct characteristics corresponding to the jets emitted from each black hole. While there is a slight chance that the jets might overlap, leading to a scenario where only one black hole is visible, researchers assert that the existence of the second black hole can be confirmed through similarly high-resolution imaging techniques, such as those offered by RadioAstron.

This breakthrough not only advances our understanding of black hole interactions but also opens up new avenues for research in astrophysics. The ability to visualize and study these cosmic giants in pairs could shed light on their formation and evolution in the universe, offering profound insights into the dynamics of galactic structures.