The James Webb Space Telescope's MIRI instrument has revealed that the early galaxy 'Virgil' hides a heavily obscured, rapidly feeding supermassive black hole that appears overmassive for its host. In ultraviolet and optical light Virgil looks like a modest, star‑forming galaxy, but mid‑infrared observations expose an energetic, dust‑enshrouded nucleus. The discovery — published Dec. 8 in Nature Astronomy — suggests many early galaxies may conceal similar black holes, challenging models that assume galaxies and their central black holes grow in lock step.
James Webb Unmasks 'Virgil' — A 'Jekyll and Hyde' Galaxy Hiding an Overmassive Black Hole
An illustration of the JWST against a "filament" of dark matter strteching many light-years through space. | Credit: ESA/Webb, NASA & CSA, G. Östlin, P. G. Perez-Gonzalez, J. Melinder, the JADES Collaboration, M. Zamani (ESA/Webb)
Astronomers using the James Webb Space Telescope (JWST) have revealed that a young galaxy nicknamed 'Virgil' conceals a heavily obscured, rapidly accreting supermassive black hole at its center. Viewed in ultraviolet and optical light, Virgil looks like a modest, star-forming galaxy; but infrared observations from Webb's Mid‑Infrared Instrument (MIRI) expose a dramatically different, energetic core.
Two Faces: A Quiet Galaxy and a Hidden Monster
'Virgil has two personalities,' said co-leader George Rieke of the University of Arizona. 'The UV and optical show its "good" side — a typical young galaxy quietly forming stars. But when MIRI data are added, Virgil transforms into the host of a heavily obscured supermassive black hole pouring out immense quantities of energy.' The dust that surrounds the galaxy's nucleus absorbs ultraviolet and visible light but is transparent to mid-infrared radiation, allowing MIRI to reveal the hidden activity.
Why This Matters
The black hole in Virgil appears far more massive than the galaxy that hosts it can plausibly support — a so‑called 'overmassive' black hole. That finding challenges prevailing models in which galaxies and their central black holes grow in tandem, suggesting instead that black holes can sometimes grow faster than their hosts in the early universe.
'It looks like the black holes actually get ahead of the galaxies in a lot of cases. That's the most exciting thing about what we're finding,' Rieke added.
Clues About the Early Universe
Virgil belongs to a population astronomers call 'Little Red Dots' — faint, red galaxies Webb is finding about 600 million years after the Big Bang. These objects are common at that epoch but appear to disappear by roughly 2 billion years after the Big Bang. The new study suggests some Little Red Dots may have evolved into dust‑enshrouded, black‑hole dominated systems like Virgil, offering a pathway to identify their descendants in the later universe.
Pierluigi Rinaldi of the Space Telescope Science Institute, a co‑leader on the study, noted the observational bias: 'Are we simply blind to its siblings because equally deep MIRI data have not yet been obtained over larger regions of the sky? JWST will have a fascinating tale to tell as it slowly strips away the disguises into a common narrative.'
Broader Implications
The result implies a potentially significant, previously hidden population of dust‑obscured, rapidly growing supermassive black holes in the early cosmos. If common, these objects could have played an important role in early galaxy evolution and in shaping the observable universe we see today.
The team's results were published on Dec. 8 in the journal Nature Astronomy.
