One of the latest discoveries related to the secrets of space involves capturing the image of a binary black hole system locked in the same orbit and interacting. The galaxy, named OJ287, is located 3,500 light-years away, and the activity of the two supermassive black holes has been documented for decades. According to Mauri Valtonen, an astronomer at the University of Turku in Finland, it is the first time that humans have been able to capture an image that reflects both black holes. One of the characteristics of this galaxy is that it belongs to the quasar type, which are the brightest in the universe thanks to the activity of the supermassive black hole.
However, this one is different from other quasars analyzed before: its brightness shows variability with a periodicity of 12 years. Observations of OJ 287 have included the use of a very long baseline interferometer (VLBI), called RadioAstron. The team’s hypothesis is that the movement of the secondary black hole should cause the deflection of the trajectory of its jet, and by comparing it with the RadioAstron radio map, they verified that it matched almost perfectly. This is a tool of modern astronomy, which has allowed the demonstration of the existence of active galaxies, whose dark matter interacts with each other.
First images
For the first time in history, scientists have been able to capture an image of two supermassive black holes locked in a single orbit. This involves the galaxy OJ 287, located about 3.5 billion light-years away, which is characterized as a quasar-type galaxy, the brightest objects in the universe.
According to astronomer Mauri Valtonen from the University of Turku in Finland, “For the first time, we managed to obtain an image of two black holes orbiting each other. In the image, the black holes are identified by the intense streams of particles they emit. Black holes are perfectly black, but they can be detected by these particle streams or by the bright gas surrounding the hole”. The importance of these images is that, despite being studied for decades, it is the first time the smoking-gun signatures of both objects have been captured.
OJ 287´s anomaly
Since 1982, astronomers have noticed that the brightness of OJ 287 changed with a 12-year periodicity. This 12-year pattern indicated that something was orbiting the primary black hole and, periodically, crossing its material disk. This led to the hypothesis that it was a binary system (two black holes). “What is special about OJ287 is that it is believed to host not one, but two black holes orbiting each other in a twelve-year orbit, producing a easily recognizable pattern of light variations over the same period,” explains Valtonen.
What happens when black holes absorb matter?
These are the scenarios that can occur with this phenomenon. On one hand, there can be an eruption of astrophysical jets because the material from the innermost edge of the disk is deflected along the magnetic field lines. When it reaches the poles, this material is ejected into space at high speed. However, in observations made so far of OJ 287, a massive jet eruption could be seen from the larger of the two black holes, an absolute unit of 18 billion times the mass of the Sun. Nevertheless, detecting a jet from the smaller of the two, with a more modest solar mass of 150 million, remained difficult.
Image acquisition
In 2014, scientists analyzed OJ 287 with a very long baseline interferometer called RadioAstron. First, the team proposed a hypothesis based on calculations of how the motion of the secondary black hole (which moves much faster than the primary) should twist the path of its jet, like a spinning garden hose. By comparing their calculations with the RadioAstron radio map, they found a jet trace that matched almost perfectly with the theoretical path of the secondary black hole. The obtained image shows the main jet crossing the galactic center diagonally, while a fainter, tilted streak matches the predicted jet of the smaller black hole.
The next step is to wait for new observations of OJ 287, which are not expected until the 2030s, when the secondary jet will again be visible from Earth.
