Black holes are the hungry monsters of space: super-dense objects that suck in anything that gets too close and tear it apart. Astronomers using the Hubble Space Telescope recently caught a black hole tearing apart and swallowing a star, creating a huge burst of radiation.
This burst of radiation, called a tidal disruption event (TDE), helped researchers pinpoint the black hole's location. The TDE, named AT2024tvd, is special for a rare reason: while most supermassive black holes are located at the center of a galaxy, this one was wandering about 2,600 light-years from the center.
" The usual location for a supermassive black hole is the center of a galaxy, such as the Milky Way's Sagittarius A (Sgr A), " explains Yuhan Yao (University of California, Berkeley), who led the study. " But this time, the black hole is not in a familiar location. This is the first TDE detected outside the center of a galaxy using optical observations. "
In addition to Hubble, the team also used NASA's Chandra X-ray Observatory and the NRAO Radio Telescope to track the TDE.
Initially, a black hole is a dark, invisible object. When a star gets too close, the black hole's immense gravity stretches the star into a 'spaghettified' shape. The star's material forms a cloud disk that rotates around the black hole and is quickly swallowed up, emitting flashes of radiation ranging from X-rays to radio waves—a sign that the black hole is not at the center of the galaxy, as expected.
The galaxy that hosts this rogue black hole also has another supermassive black hole at its center. Scientists believe this happened when two small galaxies collided and merged into a larger galaxy.
' Supermassive black holes are always at the center of galaxies, but galaxies merge to grow. When two galaxies merge, you get multiple black holes ,' said Dr. Ryan Chornock (co-author, UC Berkeley). ' Theoretical models predict that there should be rogue black holes in the galaxy. '
The team predicts that these two black holes could merge in the future, creating gravitational waves strong enough to be detected from Earth – a dramatic cosmic event!