Supermassive black holes are the most extreme objects in the known Universe, with masses millions or even billions of times greater than the mass of our Sun. Now, astronomers have been able to explore one of these giants inside a strange, distant quasar. They managed to make an amazing discovery - it twists at one third the speed of light.
The study of the supermassive black hole, located approximately 3.5 billion light years from us, is not just a feat. But it turns out that the object itself is not simple: it is a quasar that demonstrates quasi-periodic luminosities every 12 years or so. This fact has helped astronomers to identify its extreme nature.
Quasars are extremely bright accretion disks in the nuclei of galaxies, driven by an abundant amount of matter trapped in the center of a supermassive black hole. The vast majority of galaxies are believed to contain supermassive black holes. True, modern galaxies have calmed down, and quasars no longer shine. But it’s a completely different story for galaxies that are billions of light years from Earth.
The object in the center of a strange quasar called OJ287 “weighs” about 18 billion solar masses and is one of the largest supermassive (or ultramassive) black holes in the known Universe. Interestingly, it is also one of the most well-studied quasars, because it is located in close proximity to the visible path of the Sun's movement across the sky, as seen from Earth - an area where historical searches for asteroids and comets are regularly conducted. Thus, by luck, astronomers have more than 100 years of observations of the OJ287 brightness data, which allows them to predict when the following torch moments will occur. With a closer look at the glow events that have occurred in recent decades, astronomers understand that instead of a single lightening event that occurs every 12 years, clarification actually represents a double peak, providing the key to understanding what might be causing it.
Mauri Valtonen from the University of Turku, Finland, and his international team used several optical telescopes around the world in conjunction with NASA's SWIFT X-ray telescope (SWIFT) to understand that these 12-year-old double-lightening events are caused by a smaller black hole spinning around OJ287. Valtonen is the lead author of a study published in the Astrophysical Journal (Journal of Astrophysicists).
A massive black hole has a very hot accretion disk - a key component of a quasar. The material accumulates in the disk and is drawn into the black hole, feeding it. On the way, the disk material heats up and emits powerful electromagnetic radiation. The smaller black hole and partner OJ287, which itself also weighs as much as 100 solar masses (still a huge black hole!), Which has a very elongated orbit, swings close to a more massive black hole every 12 years. During the closest approach, the smaller black hole “splashes out” into the OJ287 accretion disk during the wiggle and again when it swings around the far side of the black hole, creating two different incinerations, as this diagram shows:
Illustration of the binary system of the black hole in OJ287. The predictions of the model are verified by observations.
This periodic near collision heats the accretion material of a supermassive black hole disk, quickly heating it twice directly after each other. This is what causes strange brightenings (glow) in OJ287 every 12 years. Having obtained this model of a double black hole, the researchers were able to predict when the last event should have happened. The last enlightenment occurred on November 18, 2015, just a few days before Valtonen predicted, confirming his team’s double-hole model. But with the help of these observations, the rotation of a supermassive black hole can also be calculated and it is fast. These commands show that it rotates at a third the speed of light.
Interestingly, based on historical OJ287 data, the team was also able to calculate how much energy is being lost from the system using gravity waves. Of course, gravitational waves are currently a very intriguing topic, because they were first discovered thanks to LIGO only last month. This discovery of LIGO not only confirmed Einstein’s general theory of relativity, but also directly confirmed the existence of 2 black holes merging into one whole.
Although the OJ287 gravitational waves are too weak to be detected with the help of the modern generation of gravitational wave detectors (the source is too far away), on November 18 the clarification of the quasar serves to fix the holiday of Einstein’s theory, which he presented almost 100 years ago on November 25, 1915.
