A sobbing black hole discovered by scientists

A group of researchers has found a formerly silent black hole sobbing in a distant galaxy. The observations ended up revealing a new type of binary system for these ultra-massive objects.

For those in a hurry:

• A black hole has been discovered behaving differently than expected, showing periodic oscillations;
• Theoretical physicists in the Czech Republic recently developed a theory suggesting that smaller black holes could orbit larger black holes and cause oscillations in observations.
• The team that discovered the black hole, along with theoretical physicists, pointed out that what was seen was what was previously theorized.

That was in December 2020, when a supermassive black hole was discovered about 800 million light-years from Earth from data collected by ASAS-SN (Automated All-Sky Survey for Supernovas), a network of 20 robotic telescopes that scan the sky daily. Searching for signs of supernovas and other transient phenomena.

Until the discovery was made by a team led by Dheeraj “DJ” Basham, this part of the sky was quiet and silent, so when the black hole appeared, the researchers decided to use NASA’s NICER (Neutron Star Interior Composition Explorer). Investigation into the explosion. The X-ray telescope installed on the International Space Station detected a radiation outbreak that lasted about 4 months and had periodic drops every 8.5 days.

Astronomers realized that this signal was similar to what happens when an exoplanet passes in front of a star, causing a decrease in luminosity. However, no star can cause the same effect on a supermassive black hole. This revelation made everything very strange.

While searching for a solution, Basham and his team came across a study by theoretical physicists in the Czech Republic, suggesting that a supermassive black hole could harbor a second, much smaller black hole in its accretion disk.

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A new type of black hole binary system

Theoretically, it has been suggested that this second object will periodically penetrate the first accretion disk as it orbits around it. Thus, depending on the angle at which this smaller black hole orbits the other, what Earth observatories would see would be similar to a planet passing in front of a star.

Hence, the team led by Basham discovered that what they were actually seeing was what the Czech team had assumed. Together, in a study recently published in the journal Advancement of scienceThe researchers developed a black hole simulation based on NICER and 8.5-day oscillations that supported this idea.

The smaller black hole, with a mass of about 10 to 100 thousand solar masses, will periodically penetrate the first accretion disc, which has a mass of about 50 million times the mass of the Sun, and release a cloud of gas when it does so.

These processes occurred when a third object, perhaps a star, entered this binary system and ended up being torn apart by the gravity of the larger black hole. For four months, the first object feeds on stellar material while the second black hole continues to rotate. When it entered its companion's accretion disk, it ended up releasing a much larger amount of gas than usual.

Several simulations have suggested that this is a new type of binary black hole system that researchers have dubbed David-Goliath. Furthermore, they also point out that this previously unobserved phenomenon must occur in large numbers throughout the universe, with many such pairs widespread there.

Thus, black hole accretion disks may consist of much more than just high-velocity plasma, containing other objects such as stars and even other black holes.