The cosmic web, an intricate framework of the universe, is composed of filaments and sheets made of dark matter and gas, surrounding vast, mostly empty voids. This remarkable structure serves as the backbone of the cosmos, connecting galaxies and clusters across immense distances.
Recent findings published in The Astrophysical Journal highlight the groundbreaking work of researchers utilizing COSMOS-Web, the largest survey conducted by the James Webb Space Telescope (JWST) to date. This survey examines the arrangement of galaxies within the cosmic web over a staggering 13.7 billion years of cosmic history.
JWST Transforms Cosmic Exploration
Since its launch in 2021, JWST has revolutionized our understanding of the distant universe. Its advanced infrared instruments can detect faint galaxies that were previously invisible to earlier telescopes, enabling astronomers to explore deeper into time and navigate through dense clouds of cosmic dust.
To harness these capabilities, an international team initiated COSMOS-Web, the largest General Observer (GO) program selected for JWST. This initiative covers a continuous patch of sky roughly equivalent to three full Moons and was specifically designed to map the cosmic web.
"JWST has completely transformed our perspective of the universe," stated Hossein Hatamnia, a graduate student at UCR and Carnegie Observatories, and the lead author of the study. "COSMOS-Web was crafted to provide the expansive and profound view necessary to explore the cosmic web." For the first time, researchers can analyze the evolution of galaxies within cluster and filamentary structures throughout cosmic time, from when the universe was just a billion years old to the present.
The nearby universe refers to regions within approximately 1 billion light-years from Earth, a distance light travels in one year, equivalent to about 5.88 trillion miles.
Enhanced Clarity of the Cosmic Web
Bahram Mobasher, a distinguished professor of physics and astronomy at UCR and advisor to Hatamnia, emphasized that the new JWST-based map provides significantly more detail than previous observations from the Hubble Space Telescope. He noted that earlier data often blurred together structures that JWST can now distinctly identify.
"The increase in depth and resolution is remarkable," Mobasher explained. "We can now observe the cosmic web from a time when the universe was only a few hundred million years old--an era previously beyond our reach." What once appeared as a singular structure now reveals multiple components, with details that were previously obscured now coming into focus.
The improved clarity of the map arises from two key advantages of JWST.
"The telescope identifies many more faint galaxies in the same area of the sky, and the distances to those galaxies are measured with much greater accuracy," Hatamnia added. "This allows us to position each galaxy accurately within the timeline of cosmic history, enhancing the map's resolution."
Open Access to Cosmic Web Data
In line with COSMOS's commitment to open science, the research team has made the large-scale structure maps publicly accessible. The pipeline used to create the map, along with a catalog of 164,000 galaxies and a video illustrating the evolution of the cosmic web over billions of years, is now available for public use.
The paper detailing this research is titled "Large-Scale Structure in COSMOS-Web: Tracing Galaxy Evolution in the Cosmic Web up to z ∼ 7 with the Largest JWST Survey." Collaborative efforts involved researchers from various countries, including the U.S., Denmark, Chile, France, Finland, Switzerland, Japan, China, Germany, and Italy, with funding from the European Union's Horizon 2020 program.