- Black holes go through periods of activity and dormancy, and for the first time, scientists might’ve documented a black hole as it’s “waking up.”
- First recorded in December of 2019, a new study highlights the “unprecedented” brightening behavior of a previously unremarkable galaxy, located 300 million light-years away in the constellation Virgo.
- While future studies will be needed to rule out other explanations—such as supernovas or tidal disruption events—this far-flung galaxy is helping us understand the evolution of the universe’s most massive objects.
The galaxy SDSS1335+0728, located 300 million light-years away in the constellation Virgo, seems to be experiencing an extraordinary event in real time. In December of 2019, scientists noticed that this previously unremarkable galaxy had begun to brighten sharply. To understand why this was happening, they turned to humanity’s best stargazing tools—including the European Southern Observatory’s (ESO) Very Large Telescope (VLT) and many other ground-based observatories—to get a better look.
After years of study and crunching the data, a group of researchers published a paper in the journal Astronomy & Astrophysics detailing the incredible idea that we’re witnessing the awakening of the black hole at a galaxy’s center in realtime. Well, not technically real time since the light produced from this event is 300 million years old. But like buying a used 2010 Toyota Corolla, it’s new to us.
“Imagine you’ve been observing a distant galaxy for years, and it always seemed calm and inactive,” ESO astronomer Paula Sánchez Sáez said in a press statement. “Suddenly, its [core] starts showing dramatic changes in brightness, unlike any typical events we've seen before.”
Those typical brightening events include things like supernova explosions or tidal disruption events (TDE), which is when a star traipses a bit too close to a black hole and gets absolutely shredded. While these extremely violent space phenomena can explain brief bursts of brightening that last anywhere from a few dozen to a few hundred days, what they can’t explain is why SDSS1335+0728 is still growing brighter than when it was first spotted four years ago.
Currently, the most compelling explanation is that scientists are witnessing the “awakening” of a supermassive black hole (which is at least 100,000 times more massive than our Sun) at the center of the galaxy. Combining archival data with new observations—with special credit given to the VLT’s X-shooter instrument, described by ESO as “the ultimate weapon in intermediate resolution spectroscopy”—the team found that this galaxy was emitting much more energy in ultraviolet, optical, and infrared wavelengths than it normally did. As of February of 2024, the galaxy also began emitting X-rays, which is a behavior which the research described as “unprecedented.”
Black holes can experience varying stages of activity and dormancy. When there’s nothing nearby to gobble up, a black hole becomes somewhat inactive, but can “wake up” to gobble cosmic material that strays too close. Another study from June of 2023 reported an X-ray echo that pointed to the idea that the Milky Way’s black hole, Sagittarius A* (Sgr A*), had experienced its own flare up some 200 years ago.
“These giant monsters usually are sleeping and not directly visible,” Claudio Ricci, from the Diego Portales University in Chile, said in a press statement. “This is something that could happen also to our own Sgr A*.”
To completely rule out other alternatives (like an extremely drawn-out TDE), astronomers will need to study SDSS1335+0728 more closely with other instruments on the VLT, as well as taking a peek through ESO’s upcoming Extremely Large Telescope when it comes online in 2028. Either way, this previously “unremarkable” galaxy in the Virgo constellation is now teaching us new things about the most massive objects in the known universe.
Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.
