Black holes are the voracious giants of the universe; incredibly dense entities capable of drawing in everything that comes too close, ultimately leading to its consumption. Recently, astronomers utilizing the Hubble Space Telescope witnessed a black hole actively consuming a star, tearing it apart and emitting a massive burst of radiation.
This radiation release, known as a tidal disruption event (TDE), enabled the scientists to pinpoint the black hole. The TDE designated AT2024tvd was especially intriguing for a unique reason: while most supermassive black holes reside at the centers of galaxies, this one is a nomadic outlier.
“Typically, one anticipates locating massive black holes at the core of galaxies, like Sagittarius A* in the Milky Way,” noted lead researcher Yuhan Yao from UC Berkeley. “That’s where tidal disruption events are usually sought. However, this black hole is not at the center; it’s located approximately 2,600 light years away. This marks the first optically identified off-nuclear TDE.”
In addition to Hubble, researchers employed various instruments, including NASA’s Chandra X-Ray Observatory and the NRAO Very Large Array telescope, to study the TDE depicted above.
The black hole often starts as a discreet figure in the cosmos, but when a star ventures too close, it succumbs to the black hole’s gravitational pull and becomes extended, or “spaghettified,” into a long shape. This results in a disk-like formation of debris around the black hole, which rapidly spirals in, generating a burst of radiation detectable from Earth — indicating that the black hole defies typical central placement within galaxies.
Interestingly, this galaxy houses not just one, but two supermassive black holes: one at the core and another wandering nearby. This phenomenon is believed to arise when two smaller galaxies collide and amalgamate, forming a larger galaxy.
“Massive black holes are generally positioned at the centers of galaxies, but galaxies do merge — this is a fundamental process in their growth. When two galaxies merge, they can host multiple black holes,” said co-author Ryan Chornock, also from UC Berkeley. “What happens next? While we anticipate they will eventually merge, theorists have postulated a population of black holes that roam within galaxies.”
The researchers speculate that these two supermassive black holes may eventually combine, resulting in a cataclysmic event powerful enough to produce gravitational waves that could be detected from our planet.
The study will be published in The Astrophysical Journal Letters.
