Researchers capture ancient cosmic filament in sharpest image to date
An international team of researchers has captured the most detailed image ever of a cosmic filament—an enormous strand of gas connecting two actively forming galaxies—dating back to when the universe was just 2 billion years old.
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 shown in red. Image credit: Alejandro Benitez-Llambay/Universität Mailand-Bicocca/MPA
- Researchers have captured the sharpest image of a cosmic filament, a structure spanning 3 million light-years, connecting two galaxies from when the universe was just 2 billion years old.
- Scientists directly observed intergalactic gas within the cosmic web for the first time using the MUSE spectrograph on the Very Large Telescope, overcoming previous limitations of indirect detection methods.
- Supercomputer simulations confirm that the observed filament aligns with theoretical models of dark matter distribution, refining our understanding of galaxy formation and the cosmic web’s role in shaping the universe.
The sharpest image ever captured of a cosmic filament, one of the massive structures forming the cosmic web, was obtained by an international team of researchers from the University of Milano-Bicocca and the Max Planck Institute for Astrophysics (MPA).
The filament, stretching across 3 million light-years (0.92 megaparsecs), connects two actively forming galaxies from a time when the universe was just 2 billion years old.
The research provides a glimpse into the vast network of matter shaping the large-scale structure of the cosmos.
Mapping cosmic web
The cosmic web is a fundamental structure in the universe, composed of vast filaments of dark matter and intergalactic gas. The filaments guide the formation and evolution of galaxies over billions of years, acting as channels that transport gas and matter across enormous distances.
Understanding the structure of the cosmic web allows astronomers to trace the movement of matter and gain data into galaxy formation. The arrangement of filaments follows the gravitational influence of dark matter which constitutes approximately 85% of all matter in the cosmos. Scientists can better understand how dark matter shapes the visible universe by studying the filaments.
Observing the cosmic web is challenging because of the diffuse nature of the gas within it. Unlike galaxies that emit bright light from the stars, cosmic filaments contain hydrogen gas which emits only faint radiation. Previously, studies inferred the existence of filaments indirectly by analyzing their impact on background light. Direct imaging has remained elusive, until now.
The research team used the Multi-Unit Spectroscopic Explorer (MUSE), an advanced spectrograph mounted on the Very Large Telescope at the European Southern Observatory in Chile. Over hundreds of hours of observation, they successfully imaged a filament connecting two galaxies, providing the most detailed view ever obtained of this cosmic structure.
Observing intergalactic gas
The intergalactic medium that lies between galaxies is composed mostly of hydrogen gas and serves as the main reservoir from which galaxies draw material to form stars. Detecting and mapping this gas has been a persistent challenge because of its low density and faint emissions.
“For the first time, we could trace the boundary between the gas residing in galaxies and the material contained within the cosmic web through direct measurements,” Davide Tornotti, lead researcher and Ph.D. student at the University of Milano-Bicocca, said.
Hydrogen emits ultraviolet radiation which is absorbed by Earth’s atmosphere, making ground-based observations difficult. Scientists previously relied on indirect methods such as analyzing how intergalactic gas absorbs light from distant quasars. The methods provided data but failed to produce clear images. The use of MUSE allowed researchers to overcome this limitation, enabling direct imaging of a filament for the first time.
The achievement enables scientists to study intergalactic gas properties in greater detail. Researchers can refine models of dark matter distribution and galaxy evolution by examining how gas moves within filaments and interacts with galaxies.
Simulating cosmic web
Understanding the distribution of matter in the universe requires not just observations but also sophisticated computational modeling. The researchers conducted supercomputer simulations based on the cold-dark-matter model to track how gravity influences cosmic filaments over billions of years.
Supercomputer simulations are essential in cosmology, allowing researchers to model the large-scale structure of the universe from its infancy to the present. The simulations generate realistic predictions of galaxy and filament evolution by incorporating physical laws and initial conditions derived from the Big Bang.
“When comparing to the novel high-definition image of the cosmic web, we find substantial agreement between current theory and observations,” Tornotti stated.
Comparing observational data with computational models confirms that the current understanding of dark matter and cosmic evolution remains robust. The simulations refine estimates of gas density, movement, and interaction within filaments, helping scientists determine how gas flows from cosmic filaments into galaxies, fueling their growth.
Implications for galaxy formation
The discovery provides data into how galaxies acquire the gas necessary for their growth. Cosmic filaments act as channels through which hydrogen gas flows into galaxies, fueling star formation. Understanding gas behavior in these structures helps refine galaxy evolution models.
Direct observations of gas movement within the cosmic web also shed light on feedback mechanisms such as supernova explosions and active galactic nuclei, which regulate gas flow. The processes can influence galaxy evolution by disrupting the inflow of gas. Researchers aim to identify patterns that explain variations in galaxy formation across the universe by examining multiple filaments.
“We are thrilled by this direct, high-definition observation of a cosmic filament. But as people say in Bavaria: ‘Eine ist keine’—one doesn’t count. So we are gathering further data to uncover more such structures, with the ultimate goal to have a comprehensive vision of how gas is distributed and flows in the cosmic web,” Fabrizio Arrigoni Battaia, an MPA staff scientist involved in the study, said.
References:
1 High-definition imaging of a filamentary connection between a close quasar pair at z = 3 – Davide Tornotti, Michele Fumagalli, Matteo Fossati, et al., – nature – January 29, 2025 – https://doi.org/10.1038/s41550-024-02463-w
2 Researchers capture direct high-definition image of the “Cosmic Web” – MPA – January 29, 2025
Rishika holds a Master’s in International Studies from Stella Maris College, Chennai, India, where she earned a gold medal, and an MCA from the University of Mysore, Karnataka, India. Previously, she served as a Research Assistant at the National Institute of Advanced Studies, Indian Institute of Science, Bengaluru, India. During her tenure, she contributed as a Junior Writer for Europe Monitor on the Global Politics website and as an Assistant Editor for The World This Week. Her work has also been published in The Hindu newspaper, showing her expertise in global affairs. Rishika is also a recipient of the Women Empowerment Award at the district level in Haryana, India, in 2022.
Gas in space just does not make sense to me.
Dark matter and dark energy is just as spurious.
Electro-magnetic energy?
Yep….now that makes sense….
What I see in these pics is currents of energy, not hydrogen gas being sucked into a vortex.