Galaxies aren’t just scattered across the universe; they form a network along cosmic strands called the cosmic web. These massive filaments can stretch for millions of light-years, shaping how stars and galaxies develop over time.
Astronomers have long believed that this web exists because about 85% of the universe’s matter is dark matter. This mysterious matter doesn’t interact with light, making it difficult to detect. However, computer simulations indicate that dark matter collects into these filaments due to gravitational forces.
Gas, especially hydrogen, also follows these filaments. It feeds the galaxies located where these strands intersect. Detecting the faint glow of hydrogen gas has been a challenge until recent studies brought new insights.
This exciting research was led by Davide Tornotti, a Ph.D. student at the University of Milano-Bicocca, along with the Max Planck Institute for Astrophysics (MPA).
In their investigation, the team used an advanced telescope in Chile called the Very Large Telescope (VLT) with an instrument known as MUSE (Multi-Unit Spectroscopic Explorer) to closely observe a filament connecting two galaxies from about 2 billion years ago. They spent hundreds of hours analyzing a specific part of the sky, leading to a high-definition image of a filament about 3 million light-years long.
This image revealed that the gas within the filament plays a crucial role in forming new stars. For the first time, researchers could trace the filament’s boundary in detail and showed a direct link between the gas in the filament and the gas in the galaxies, helping to explain how galaxies evolve over time.
Tornotti noted, “By capturing the faint light from this filament, which traveled almost 12 billion years to reach us, we were able to shape its profile.” This clarity was possible thanks to MUSE’s design, which allows astronomers to detect weak emissions that can easily be lost in brighter backgrounds.
When the researchers compared their findings with computer models from MPA, they found strong agreement, lending more credibility to current theories about how dark matter influences galaxy formation.
The results show that galaxies depend on these filaments to receive fresh gas. These strands act as a backbone for the formation of galactic structures, guiding both dark and normal matter into star clusters. This study illustrates the relationship between observations and theoretical models in astronomy.
As Tornotti mentioned, “While we’re thrilled with this observation, we want to gather more data.” The team aims to discover additional filaments, providing a wider understanding of how gas flows in the cosmic web. This ongoing research could change how we view cosmic activity and confirm whether galaxy formation follows a similar pattern across different regions of the universe.
These high-resolution views of the cosmic web, once a distant dream, now help us understand gas behaviors across vast distances. This single observation has significantly advanced our knowledge of the processes driving galaxy growth, showcasing the importance of persistence in uncovering the universe’s hidden signals.
The findings were published in Nature Astronomy.
