How Supermassive Black Holes Formed in the Early Universe: A New Study Reveals

Supermassive black holes are some of the most mysterious and fascinating objects in the cosmos. They are so massive that nothing, not even light, can escape their gravitational pull. They are also so powerful that they can shape the evolution of galaxies and influence the formation of stars and planets. But how did these colossal cosmic monsters come to be? How did they grow so quickly in the early universe, when everything else was still young and small?

A new study by a team of researchers from the University of California, Berkeley, and the Max Planck Institute for Astrophysics in Germany has made significant advances in answering these questions. In this article, we will explore what supermassive black holes are, how they formed in the early universe according to the new study, what tools researchers used to get these results, and what makes this study and results different from what we know already.

What are supermassive black holes?

A black hole is a region of space where gravity is so strong that nothing can escape from it, not even light. The boundary of a black hole is called the event horizon, and the point of no return for anything that crosses it is called the singularity. Black holes can have different sizes and masses, depending on how they formed and how much matter they have swallowed. The smallest black holes are called primordial black holes, and they may have formed in the first moments after the Big Bang.

The most common black holes are called stellar black holes, and they form when massive stars collapse at the end of their lives. The largest black holes are called supermassive black holes, and they have masses millions or billions of times greater than the sun. Supermassive black holes are found at the centres of most galaxies, including our own Milky Way. They can have a diameter of several light-years, and their gravity can affect everything around them.

For example, some supermassive black holes can produce powerful jets of radiation and matter that can extend for thousands of light-years. Some supermassive black holes can also devour nearby stars and gas, creating bright disks of hot material called accretion disks. These disks can emit enormous amounts of energy, making the supermassive black holes visible across the universe as quasars or active galactic nuclei.

How did supermassive black holes form in the early universe?

One of the biggest puzzles in astrophysics is how supermassive black holes formed in the early universe when everything else was still young and small. According to the standard theory, supermassive black holes grew from smaller seeds that were either primordial black holes or stellar black holes. However, this theory faces several challenges, such as explaining how these seeds grew fast enough to reach supermassive sizes in a short time, and how they avoided being starved by feedback effects from their own radiation.

A new study by a team of researchers from the University of California, Berkeley, and the Max Planck Institute for Astrophysics in Germany has proposed a different scenario for the formation of supermassive black holes in the early universe. According to their study, supermassive black holes formed directly from massive clouds of gas that collapsed under their own gravity without forming stars first. These clouds were rare and special, because they had very low metallicity (meaning they contained very few elements heavier than hydrogen and helium), very high density (meaning they contained a lot of mass in a small volume), and very low angular momentum (meaning they had very little rotation).

These conditions allowed the clouds to avoid fragmentation into smaller pieces that would form stars, and instead collapse into a single dense core that would form a supermassive black hole. The researchers used high-resolution simulations of galaxy mergers to study this scenario and found that it could produce supermassive black holes with masses up to 10 billion times that of the sun in less than a billion years after the Big Bang.

What tools did researchers use to get these results?

The researchers used a combination of theoretical models and numerical simulations to explore their scenario for the formation of supermassive black holes in the early universe. They used a cosmological simulation code called Gadget-3 to model the evolution of dark matter and gas in a large volume of space from shortly after the Big Bang until about one billion years later.

They then used a zoom-in technique to focus on regions where galaxy mergers occurred, and where massive gas clouds could form. They used another simulation code called Arepo to model these regions with higher resolution and more physics, such as cooling, heating, chemistry, turbulence, magnetic fields, and star formation.

They also used a sub-grid model to track the formation and growth of black holes within these regions. They ran several simulations with different initial conditions and parameters to test their scenario under various circumstances.

What makes this study and its results different from what we know already?

This study and results are different from what we know already because they challenge the standard theory of supermassive black hole formation, and offer a new way to explain how these cosmic giants came to be. The study also provides new insights into the physical processes that governed the early universe, and how they influenced the formation of galaxies and stars.

The study also has implications for the observation of supermassive black holes and their environments, both in the present and in the past. For example, the study predicts that supermassive black holes formed from massive gas clouds should have different properties and signatures than those formed from smaller seeds, such as their masses, spins, accretion rates, and radiation spectra.

These differences could be detected by current and future telescopes, such as the James Webb Space Telescope, the Event Horizon Telescope, and the Laser Interferometer Space Antenna.

The study also suggests that supermassive black holes formed from massive gas clouds could have played a significant role in the reionization of the universe, which is the process by which the first stars and galaxies ionized the neutral hydrogen that filled the space between them. This process is one of the key milestones in the history of the universe, and its details are still poorly understood.

Conclusion

Supermassive black holes are some of the most mysterious and fascinating objects in the cosmos. They are also some of the most elusive and challenging to study. A new study by a team of researchers from the University of California, Berkeley, and the Max Planck Institute for Astrophysics in Germany has made significant advances in understanding how these colossal cosmic monsters formed in the early universe.

The study proposes that supermassive black holes formed directly from massive clouds of gas that collapsed under their own gravity without forming stars first. The study uses a combination of theoretical models and numerical simulations to test this scenario and finds that it could produce supermassive black holes with masses up to 10 billion times that of the sun in less than a billion years after the Big Bang.

The study also has implications for the observation of supermassive black holes and their environments, both in the present and in the past, as well as for the evolution of galaxies and stars, and the reionization of the universe. The study is a remarkable example of how modern astrophysics can explore some of the most fundamental questions about our universe and its origins.

Paper link:
https://iopscience.iop.org/article/10.3847/1538-4357/acd841