A latest study led by the University of Oxford in the United Kingdom and the Center for Astrobiology in Spain (CAB) shows that the James Webb Space Telescope (JWST) detected an abundance of small-molecule organic compounds far exceeding theoretical expectations in an infrared bright galaxy core that was severely obscured by dust, revealing a complex organic chemical environment that has never been directly confirmed outside the Milky Way before.
Researchers pointed out that high-energy cosmic rays may be continuously bombarding carbon-rich dust particles and polycyclic aromatic hydrocarbons (PAHs) deep in the galaxy, breaking them into pieces and continuously producing smaller organic molecules, making these deeply buried galactic nuclei a powerful "organic molecule production center" in the universe.
The study targeted the ultra-bright infrared galaxy IRAS 07251–0248. The central region of the galaxy is wrapped in extremely dense gas and dust, so that the supermassive black hole at the center and surrounding activities are almost completely blocked in the visible light band, making it difficult for conventional telescopes to peer into its interior. However, light in the infrared band can penetrate dust. The James Webb Telescope took advantage of this to conduct in-depth observations of its buried galactic core, allowing it to determine what chemical processes dominate this extreme environment.
The research team used JWST's near-infrared and mid-infrared spectral data to conduct a detailed analysis of radiation in the wavelength range of 3-28 microns. Combining spectral lines obtained by NIRSpec and mid-infrared instruments, they identified the characteristic "fingerprints" of gas-phase molecules, ice-like inclusions, and dust particles. By modeling these spectral features, scientists are able to deduce the abundance and temperature distribution of various compounds in the galaxy core and draw an unprecedented "chemical structure picture."
The results show that there are an unusually rich variety of small organic molecules inside the buried galaxy core, including a series of carbon and hydrogen-containing molecules such as benzene (C₆H₆), methane (CH₄), acetylene (C₂H₂), diacetylene (C₄H₂) and triacetylene (C₆H₂). The team also directly detected methyl radicals (CH₃) for the first time outside the Milky Way, a discovery that further highlights the complexity of organic chemical networks in this region. In addition to gas phase molecules, observations also revealed the existence of a large number of solid materials, including carbon-rich dust particles and water ice, providing important clues to explain the source of carbon.
The first author of the paper, Ismael Garcia-Bernet, who worked at the University of Oxford and currently works at the Center for Astrobiology, said that the observed abundance of small organic molecules is much higher than expected by existing theoretical models, implying that there must be a continuous source of carbon in the galaxy's core, driving this complex and efficient chemical network. The team's analysis shows that high temperature or turbulence alone is not enough to explain this chemical enrichment phenomenon. A more reasonable explanation is that high-energy cosmic rays play a key role in it.
Using the theoretical model and analysis method of polycyclic aromatic hydrocarbons developed by the Oxford team, the researchers found that the cosmic rays filled in these extreme galactic nuclei will frequently hit PAHs and carbon-rich dust particles, shattering the originally larger carbon-based structures and releasing a large number of smaller organic molecules into the gas. In several similar galaxies, the study also found a significant correlation between the abundance of hydrocarbon molecules and the level of cosmic ray ionization. This statistical evidence further supports the picture of "cosmic ray-driven organic chemical factories."
Although the small organic molecules detected this time do not constitute life in themselves, they are considered to be one of the key raw materials for higher-order "prebiochemistry". Co-author Dimitra Rigopoulou, professor of physics at the University of Oxford, pointed out that although such small molecules do not appear directly in living cells, they may play an important role before forming basic molecules of life such as amino acids and nucleotides, and represent a key intermediate link from inorganic substances to complex organic systems.
The researchers suggest that galactic nuclei like IRAS 07251–0248, which are buried in thick dust, may play a far more important role in the chemical evolution of the universe than previously thought. They are not only the energy centers of violent activity of stars and black holes, they may also be "workshops" for the synthesis and processing of large-scale organic molecules, continuously transporting a variety of organic compounds into the galaxy and even into the wider interstellar space, thus affecting the chemical composition and evolutionary trajectory of the entire galaxy.
This work demonstrates the James Webb Space Telescope's unique ability to detect chemical processes in extreme environments, allowing scientists to take the first systematic look at chemical activity in buried galactic nuclei that was previously almost completely invisible. Relevant results have been published in the journal Nature Astronomy on February 6, 2026. The paper is titled "Abundant Hydrocarbons, Carbonaceous Dust Particles and Signs of Polycyclic Aromatic Hydrocarbon Processing in Buried Galactic Cores", which further provides key observational evidence for understanding how carbon and complex organic molecules are generated and evolve in the universe.