In the 1960s, astronomers began to theorize that there could be black holes in the Universe that are so massive (supermassive black holes (SMBH)) that they could power the nuclei of active galaxies (also known as quasars). A decade later, astronomers discovered that an SMBH existed in the center of the Milky Way (Sagitarrius A *); And in the 1990s, it became clear that most of the Universe’s large galaxies likely have one.
Since then, astronomers have been searching for the largest SMBH they can find, hoping they can see how massive these things get! And thanks to new research led by astronomers from the National University of Australia, the latest undisputed heavyweight contender has been found! At approximately 34 billion times the mass of our Sun, this SMBH (J2157) is the fastest growing black hole and largest quasar observed to date.
The team’s study, which recently appeared on Monthly notices from the Royal Astronomical Society, was chaired by Dr. Christopher A. Onken, the operations manager for the SkyMapper telescope. He was joined by researchers from the School of Research in Astronomy and Astrophysics (RSAA) and the Center for Gravity Astrophysics (CGA) at ANU, as well as the European Southern Observatory (ESO) and the Steward Observatory.
The same team was responsible for discovering J2157, which they did in 2018, using data from the Gaia observatory the Wide Field Infrared Survey Explorer (WISE) space telescope, and the SkyMapper Southern Sky Survey. That particular study was led by Christian Wolf, a member of the Australian Sky Council Center for Excellence in Astrophysics of Sky (CAASTRO), who also participated in this latest study.
As they indicated at the time, J2157 is the brightest quasar observed in the Universe known to date, which they attributed to the presence of an SMBH at its center. Furthermore, they were able to rule out the possibility that its luminosity was the result of gravitational lenses, where the presence of intervening galaxies and other massive objects were responsible for increasing the brightness of J2157.
This was a great possibility, given that J2157 light is visible 12.5 billion light-years from Earth, and therefore has to travel a great distance in space and time to reach us. For this latest study, Dr. Onken and the team relied on data from ESO’s Very Large Telescope (VLT) in Chile to limit the distance and mass of this SMBH in the core of J2157. As Dr. Onken said in a recent ANU press release, what they found was quite surprising:
“The mass of the black hole is also approximately 8,000 times larger than the black hole at the center of the Milky Way. If the Milky Way’s black hole wanted to get fat, it would have to swallow two-thirds of all the stars in our galaxy. We are looking at it at a time when the universe was only 1.2 billion years old, less than 10 percent of its current age. It is the largest black hole ever weighed in this early period of the Universe. “
The team already had indications that J2157 contained a fast-growing SMBH that consumed stars in the central region of their galaxy on a regular basis. But the fact that it was the fastest growing SMBH in the Universe, just 1.2 billion years after the Big Bang, was astonishing. As Dr. Fuyan Bian, staff astronomer at the European Southern Observatory (ESO) said:
“We knew we were in a very massive black hole when we realized its rapid growth rate. The number of black holes they can swallow depends on how much mass they already have. So, for it to be devouring matter at such a high rate, we thought it could become a new record holder. And now we know.
But equally significant is what J2157 can teach us about the early Universe and its later evolution. For some time, astronomers have been looking for more examples of SMBH in the early Universe to see how they affected the evolution of galaxies and the cosmos as a whole. At the same time, they have been searching for answers on how SMBHs could have grown so much in such a short time.
While these questions remain unsolved, the discovery of this ancient and more massive supermassive black hole could provide some very useful clues. The team behind this discovery is already looking for more black holes that existed at the center of galaxies shortly after the Big Bang, in hopes that they can find some additional clues.
Said team member, Dr. Fuyan Bian, staff astronomer at the European Southern Observatory (ESO):
With such a huge black hole, we are also excited to see what we can learn about the galaxy in which it is growing. Is this galaxy one of the giants of the early Universe, or did the black hole swallow an extraordinary amount from its surroundings? We will have to keep digging to solve that. ”
One of the most important developments in the fields of astronomy and astrophysics in recent decades has been the ability to see further and more clearly. By looking deeper into the cosmos, they have also been able to look further back in time and see what the Universe was like at a very young age. This has allowed scientists to test cosmological theories about how the Universe has grown and evolved since then.
With all the new developments expected in the ensuing years and decades, including the deployment of next-generation telescopes, artificial intelligence, and machine learning, and increased data sharing, scientists anticipate that the most enduring cosmological questions will soon be. answered!
Further reading: ANU, MNRAS
