A professor in Abu Dhabi has found a rare black hole at the centre of a small and distant galaxy.
It was discovered in the IC 750 galaxy – about 45 million light years away – and is unique because of its intermediate size, which is difficult to find.
The discovery could provide an insight into the mysteries of supermassive black holes and their host galaxies.
Black holes form when a massive star collapses and starts to suck in nearby stars – not even light can escape their pull.
There is limited data about supermassive and small, or stellar, black holes, and scientists have been trying to learn more about intermediates.
Prof Ingyin Zaw, an associate professor of physics at NYU Abu Dhabi, revealed the black hole is 100 times too small relative to the galaxy it lives in.
This is unique as black holes and galaxies are known to grow equally together.
“One of the questions my research touches on is: are there any black holes in the intermediate range?
“Even though the black holes themselves are much smaller than their host galaxies, somehow it’s like they know about each other’s mass,” Prof Zaw said.
The mass of a black hole is usually measured in solar mass, which is the mass of the Sun. A small black hole has a mass of between about three and 10 solar masses and is formed when a star explodes, while a supermassive black hole is huge, with millions to billions of solar masses, and is thought to involve many stars.
But not much is known about how intermediates form.
Prof Zaw’s findings raise questions of whether intermediate black holes in small galaxies grow differently than supermassive and small ones.
Her research was funded by Mohammed bin Rashid Space Centre and the findings were published in The Astrophysical Journal.
In 2019, an image of a black hole was revealed by scientists for the first time, specifically of a supermassive one in the M87 galaxy.
It had a mass more than six billion times that of the Sun, and the picture helped to prove astronomers’ theories about gargantuan black holes.
Prof Zaw and her team used the very long baseline array – 10 telescopes spread out between Hawaii and the US Virgin Islands that act as one big telescope – to obtain radio observations of the low-mass galaxy.
They studied the water maser emissions, which are audio frequencies of electromagnetic waves, to understand the black hole’s mass. These were being emitted from clouds of water vapour that were orbiting the black hole.
The team is now carrying out follow-up studies of the black hole to improve the measurement of its mass and determine how much material is falling into it.
They are also searching for water emissions from other small galaxies.
Once complete, it is hoped the study will shed more light on mysteries of how black holes are formed.
