Black holes are one of the most mysterious and fascinating objects in the universe. They are regions of space where gravity is so strong that nothing, not even light, can escape. Scientists are studying black holes for decades but still, we know very little about them.
One of the biggest questions is how black holes form and grow. Depending on their size and origin, different types of black holes exist. The smallest ones are called primordial black holes, which may have formed in the early moments of the Big Bang. The most common ones are called stellar black holes, and they form when massive stars collapse at the end of their lives. The largest ones are called supermassive black holes, and they lurk at the centres of galaxies, with masses millions or billions of times that of the sun.
It is believed that supermassive black holes have a significant impact on the development of galaxies, affecting their size, shape, and star formation. But how do they get so big? One possibility is that they grow by merging with other black holes or accreting matter from their surroundings. Another possibility is that they are born supermassive, from the collapse of huge clouds of gas in the early universe.
Recently, a team of scientists from Durham University in the UK have discovered a new type of supermassive black hole that challenges our understanding of how they form and grow. The black hole is located in a galaxy called SAGE0536AGN, about 9 billion light-years away from Earth. It has a mass of about 350 million times that of the sun, which is unusually large for a galaxy of its size and age
The researchers used data from several telescopes, including NASA's Chandra X-ray Observatory and ESA's XMM-Newton, to measure the properties of the black hole and its host galaxy. They found that the black hole accounts for about 10% of the galaxy's total mass, which is much higher than the typical ratio of 0.1% to 0.5%. They also found that the galaxy is relatively young, only about 1.2 billion years old, which means that the black hole must have grown very fast in a short time.
The team ruled out several scenarios that could explain the existence of such a massive black hole in such a young galaxy. They concluded that the most likely explanation is that the black hole was born supermassive, from the direct collapse of a massive gas cloud that bypassed the formation of stars. This process is predicted by some theoretical models, but it has never been observed before.
The discovery of this new type of supermassive black hole has important implications for our understanding of how galaxies and black holes co-evolve. It also opens up new possibilities for finding more examples of these rare and extreme objects in the distant universe.
The team published their findings in the Monthly Notices of the Royal Astronomical Society in March 2023. You can read more about their research on their website: https://www.dur.ac.uk/physics/research/cosmology/sage0536agn/