Astronomers at MIT and Columbia University have used the James Webb Space Telescope (JWST) to study a phenomenon known as tidal disruption events (TDEs). These events occur when a galaxy’s central black hole draws in a nearby star, causing a massive burst of energy. Scientists had previously observed about 100 TDEs, but many more are believed to exist in dusty, gas-veiled galaxies.
Using JWST’s powerful infrared capabilities, the researchers detected clear fingerprints of black hole accretion in four dusty galaxies. They also found patterns that differed significantly from those around active galaxies. These observations confirmed that tidal disruption events did indeed occur in each of the four galaxies and revealed key differences in the environments around dormant versus active black holes.
The study’s findings suggest that the four events were powered by dormant black holes, which experienced little to no activity until a star happened to pass by. The researchers used JWST to search for specific spectral lines, or infrared light at particular wavelengths, that would indicate conditions associated with a tidal disruption event. These measurements confirmed the presence of black hole accretion in all four galaxies.
To differentiate between dormant and active black holes, the team compared the patterns of dust in each galaxy to those of active galaxies. They found that the patterns were significantly different, suggesting that the black holes at the center of each galaxy are not normally active. Instead, they believe that the accretion disk formed around these black holes was a result of a tidal disruption event.
The researchers plan to uncover many more previously hidden TDEs using JWST and other infrared telescopes. By studying these events, scientists hope to gain insight into fundamental properties of black holes, such as their mass and spin. The discovery of dormant black holes with accretion disks could provide new clues about the behavior of these mysterious objects.
Source: https://news.mit.edu/2025/astronomers-discover-star-shredding-black-holes-hiding-in-dusty-galaxies-0724