Virgil: Jekyll-and-Hyde galaxy

The JWST examined a puzzling a galaxy from when the Universe was only about 800 million years old. When observed in visible and UV light, it appears much like any other galaxy. But in infrared, the JWST can see its supermassive black hole, which is accreting massive amounts of matter and emitting extreme radiation. Image Credit: ESA/Webb, NASA & CSA, G. Östlin, P. G. Perez-Gonzalez, J. Melinder, the JADES Collaboration, M. Zamani (ESA/Webb)

Recently, the James Webb Space Telescope (JWST) uncovered a distant galaxy that astronomers nicknamed Virgil. In optical and ultraviolet light it looks like a typical star-forming galaxy in the early universe. But when JWST observed it in infrared light, using its Mid-Infrared Instrument (MIRI),  what appeared was a hidden, heavily obscured, rapidly growing supermassive black hole at its center. This massive black hole emits vast amounts of energy that are blocked by dust in other wavelengths, making the galaxy appear ordinary unless seen in infrared. This duality has earned Virgil its special “Jekyll-and-Hyde” title. 

JWST sees Virgil as it existed just 800 million years after the Big Bang. At that early stage in cosmic history, black holes were not expected to grow so large so fast. Yet this one is overmassive, far larger than its host galaxy should be able to support.

Virgil belongs to a mysterious group known as “Little Red Dots,” early galaxies that appear unusually red and compact. JWST has, so far, observed about 300 of them. Its discovery challenges existing theories about how black holes and galaxies evolve together, suggesting black holes may sometimes grow faster than their host galaxies. And instead of galaxies slowly growing black holes at its center, some black holes may have formed first, growing from the inside out. 

The team at the University of Arizona are taking the lead in making further MIRI observations to determine if the early universe is full of hidden black holes that we are just beginning to see.