Astronomers have used the James Webb Space Telescope (JWST) to map the “cosmic web,” the largest known structure in existence, in unprecedented detail. According to a study published May 6 in The Astrophysical Journal, this survey reveals how gas, dark matter, and galaxies formed a scaffolding across space over 13 billion years. Led by researchers from the University of California, Riverside (UCR), the research provides a clearer view of galaxy evolution than previous maps.
How does the cosmic web structure the universe?
The cosmic web acts as the framework of the universe. It consists of a vast network of gas filaments, stars, voids, sheets of dark matter, and clusters of galaxies. Researchers describe it as the “skeleton” of the cosmos, which traces the large-scale organization of the universe. According to the UCR team, this structure has evolved significantly since the infancy of the universe, influencing where galaxies grow and where they eventually stop forming stars.
The COSMOS-Web survey covered a contiguous area of the sky equivalent to the size of three full moons, utilizing 255 hours of JWST observation time.
Why is the new JWST map more accurate than previous versions?
The new COSMOS-Web survey offers a significant leap in data quality compared to the 2021 COSMOS2020 survey. According to the study authors, previous maps often struggled with depth accuracy, frequently overestimating density in crowded regions and underestimating it in empty space. The JWST’s superior sensitivity allows for better redshift precision, enabling scientists to map fainter, lower-mass, and more distant galaxies that were previously invisible or appeared as blurry, indistinct blobs.
What determines the life and death of a galaxy?
Galaxy growth is governed by both internal and external factors, according to the research team. At earlier stages of the universe, dense regions served as hubs for rapid galaxy formation. However, in the more recent universe, these same dense environments are often associated with “quenched” star formation, where galaxies cease producing new stars.
The study suggests two primary reasons for this decline:
- Mass limits: Once dark matter halos anchoring a galaxy reach 1 trillion solar masses, they can energize surrounding gas, preventing it from cooling and coalescing into stars.
- Supermassive black holes: Active black holes can emit near-light-speed jets that heat up galactic gas, effectively shutting down star formation.
The catalog of 164,000 galaxies identified by the researchers is now publicly available for independent scientific analysis.
What is the future of cosmic mapping?
The ability to observe the universe as it existed only a few hundred million years after the Big Bang opens new doors for cosmology. Bahram Mobasher, a distinguished professor of physics and astronomy at UCR, noted that this era was effectively out of reach before the JWST. Future research will likely focus on how these earliest structures set the stage for the peak era of star formation, which is many billions of years behind us.
Frequently Asked Questions
What is the cosmic web?
It is the framework of the universe composed of dark matter, gas filaments, stars, voids, and galaxy clusters.
How does the JWST see further than previous telescopes?
The JWST has higher sensitivity and resolution, allowing it to detect fainter, lower-mass, and more distant light that was previously obscured or too dim for previous maps to resolve clearly.
What does “quenched” mean in astronomy?
Quenching refers to the process by which a galaxy stops forming new stars, often due to environmental factors or internal energy processes like black hole activity.
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