In a groundbreaking advancement for cosmology, an international team of researchers has obtained the sharpest image to date of a cosmic filament connecting two forming galaxies. This discovery, made after hundreds of hours of observation with the MUSE spectrograph at the Very Large Telescope of the European Southern Observatory (ESO) in Chile, allows for an unprecedentedly precise characterization of the structure of the cosmic web.

For decades, cosmologists have theorized that matter in the Universe is not distributed homogeneously but instead organizes itself into a vast network of interconnected filaments. This cosmic web, composed mainly of dark matter and intergalactic gas, serves as a scaffold upon which galaxies and other astronomical objects form. At the intersections of these filaments, where gravity concentrates larger amounts of matter, the brightest galaxies emerge.

One of the greatest challenges in astronomy has been the direct observation of these filaments, as intergalactic gas is extremely diffuse and emits a very faint glow. Until now, their existence could only be inferred indirectly through the absorption of light from distant sources. However, previous-generation instruments lacked the sensitivity necessary to capture the direct emission of these filaments.

Cosmic web high definition
Made of gas clumped together by the influence of dark matter, the filament stretches out for 3 million light-years, connecting two distant galaxies in the early Universe. Credit: ESO/D. Tornotti et al./Hubble: M. Revalski, P. Francis et al.

An Unprecedented Achievement in Cosmic Observation

The new study, led by Davide Tornotti, a doctoral candidate at the University of Milan-Bicocca, marks a milestone in the observation of the cosmos. Thanks to the ultra-precise capabilities of the MUSE spectrograph, scientists were able to capture the most detailed image of a cosmic filament stretching over three million light-years and connecting two active galaxies, each harboring a supermassive black hole at its core.

The team spent hundreds of hours observing to collect data with high statistical significance, thus achieving an accurate characterization of the filament. This image, recently published in Nature Astronomy, allows, for the first time, a distinction between the gas contained within galaxies and the material present in the cosmic web.

The finding not only represents a milestone in the observation of the Universe, but it also provides empirical confirmation of computer simulations conducted at the Max Planck Institute for Astrophysics. These simulations predict the expected emission of cosmic filaments based on the current cosmological model. By comparing the high-definition image of the filament with our simulations, we found a substantial match between theory and observation, Tornotti notes.

Cosmic web high definition
Simulation of a vast region of the Universe based on the current cosmological model and performed using supercomputers. In the image, the faint glow of the gas within the cosmic filaments, forming a dense cosmic web, is shown in white. At the intersections of these filaments, the gas within galaxies, which fuels the formation of new stars, is highlighted in red. Credit: Alejandro Benitez-Llambay/Universität Mailand-Bicocca/MPA

The discovery opens new possibilities for studying galactic evolution and the dynamics of intergalactic gas. The direct observation of these filaments will allow scientists to better understand how gas is supplied to galaxies and how it influences star formation.

Fabrizio Arrigoni Battaia, a researcher at the Max Planck Institute and co-author of the study, emphasizes the importance of continuing to explore these structures: We are excited about this high-definition observation of a cosmic filament, but as they say in Bavaria: ‘Eine ist keine’—one is not enough. That’s why we continue gathering more data to uncover additional filaments and obtain a comprehensive view of the cosmic web.

This study represents a significant step in understanding the architecture of the Universe and paves the way for future observations with even more advanced technologies. The ability to analyze the cosmic web in detail will help solve some of the fundamental mysteries regarding galaxy formation and cosmic evolution.

SOURCES

Max Planck Institute for Astrophysics

Tornotti, D., Fumagalli, M., Fossati, M. et al. High-definition imaging of a filamentary connection between a close quasar pair at z = 3. Nat Astron (2025). doi.org/10.1038/s41550-024-02463-w

  • Share on:

Discover more from LBV Magazine English Edition

Subscribe to get the latest posts sent to your email.

Something went wrong. Please refresh the page and/or try again.

Follow LBV Magazine on Google News