The Circinus Galaxy, about 13 million light-years away, hosts an active galactic nucleus — a supermassive black hole busily devouring gas and blazing across the spectrum. For decades it has also hosted an argument: where, exactly, does the excess infrared glow from the hot dust around such a black hole come from? New observations with the James Webb Space Telescope have resolved the galaxy's heart in unprecedented detail and delivered an answer that overturns the prevailing assumption.
A telescope acting like several
The breakthrough came from an unusual technique. Rather than relying on a conventional image, the team used the Aperture Masking Interferometer mode of Webb's NIRISS instrument, which works by treating the telescope's aperture as an array of smaller sub-telescopes and combining their light. The effect is to roughly double Webb's resolution — the equivalent, the researchers say, of observing with a 13-metre space telescope rather than its actual 6.5-metre mirror. That extra sharpness was what allowed them to disentangle the crowded structures packed into the galaxy's nucleus: the dusty torus, the accretion disk, and the outflows of superheated matter streaming from the black hole.
The result, reversed
Earlier models had concluded that the outflows — the winds of hot material driven away from the black hole — dominated the infrared emission. Webb found close to the opposite. Roughly 87 percent of the hot-dust infrared glow originates from the regions closest to the black hole, while less than 1 percent comes from the dusty outflows. In other words, the excess infrared light that had puzzled astronomers since the 1990s is produced almost entirely in the immediate vicinity of the black hole, not in the material being expelled.
"Since the '90s, it has not been possible to explain excess infrared emissions from hot dust at active galaxy cores," said Enrique Lopez-Rodriguez of the University of South Carolina, who led the study, published in Nature on January 13, 2026. Resolving that long-standing discrepancy does more than tidy up one galaxy's books. The structure of dust and gas around feeding black holes governs how we interpret active galactic nuclei across the universe, many of which are too distant to resolve directly. A clear, nearby example — dissected at high resolution — becomes a template for reading the unresolved many, anchoring models of how matter funnels into the most powerful engines in the cosmos.
The donut at the heart of the unified model
The reason astronomers care so much about the dusty torus is that it underpins the "unified model" of active galactic nuclei — the idea that the bewildering variety of feeding black holes we observe are largely the same kind of object viewed from different angles. Look down the axis and you see straight into the brilliant accretion disk; look edge-on and the obscuring torus hides the central engine, changing the galaxy's apparent character entirely. Pinning down where the torus's heat actually comes from, and how it is arranged, is therefore not a niche question — it calibrates the lens through which essentially all active galaxies are interpreted.
Turning one galaxy into a key for many
Circinus is valuable because it is close enough to dissect. The overwhelming majority of active galactic nuclei lie far too distant for any telescope to resolve their inner structure; they are points of light whose properties must be inferred. By resolving a nearby example at the equivalent of 13-metre-telescope sharpness, Webb provides a ground truth against which those distant, unresolved sources can be modelled. Settling the 30-year-old infrared puzzle here means the same physics can be applied with more confidence everywhere else — a single well-studied galaxy serving as a key to thousands that will never be seen so clearly. It is a recurring theme of the Webb era: the telescope's resolving power lets astronomers turn a handful of nearby, dissectible objects into Rosetta stones for interpreting the faint, unresolved multitudes that fill the distant universe.
