Latest news with #eROSITA
Yahoo
16-04-2025
- Science
- Yahoo
Long-dormant black hole 'woke up' before our eyes — now, it's doing something that astronomers can't explain
When you buy through links on our articles, Future and its syndication partners may earn a commission. In December 2019, an ordinary galaxy 300 million light-years from us in the constellation Virgo suddenly woke up. After decades of inactivity, the black hole at the galaxy's heart burst with light. Now, the cosmic monster appears to be doing something that is forcing astronomers to re-evaluate their understanding of these massive celestial bodies. The black hole now gives off powerful X-rays at nearly regular intervals. These outbursts are known as quasi-periodic eruptions (QPEs), and have been observed emitting from other black holes. But the bursts observed here are up to 100 times more powerful than normal, according to new research. First observed in February 2024 by astronomers at Valparaiso University in Chile, this behavior grants scientists an unprecedented view of a black hole that seems to be awakening from dormancy with no sign of going back to sleep. Led by the Valparaiso team, a group of researchers published their observations of the black hole's QPE in a study on April 11 in the journal Nature Astronomy. In addition to giving astronomers a novel view of black holes, these events are also spurring researchers to reconsider how black holes behave. "This is the first time we have observed such an event in a black hole that seems to be waking up," the paper's first author Lorena Hernández-García, an astronomy researcher at Valparaiso University, said in a statement. "This rare event provides an opportunity for astronomers to observe a black hole's behaviour in real time." Related: Supermassive black hole at the heart of the Milky Way is approaching the cosmic speed limit, dragging space-time along with it The galaxy, called SDSS1335+0728, first called attention to itself in 2019 when it unexpectedly started gleaming. At that time, astronomers from the European Southern Observatory studied the event by consulting NASA's Swift X-ray space telescope and data from the eROSITA X-ray telescope. After investigating the galaxy's central region — nicknamed Ansky — they concluded that the flash resulted from Ansky's massive black hole beginning an active phase. But in February 2024, Hernández-García's team noticed bursts of previously undetected X-rays emanating from Ansky, caught by X-ray space telescopes XMM-Newton and NASA's NICER, Chandra, and Swift. These QPEs are momentary, recurring X-ray flares. Astronomers believe QPEs result from interaction between accretion disks — the swirling ring of red-hot matter that surrounds a black hole — and nearby objects, like a star or a smaller black hole. But Ansky's QPEs aren't typical. They're remarkable because they last 10 times longer and are 10 times more luminous than average QPEs, the researchers said. Persisting for more than four days, they each release one hundred times more energy than what's expected. These QPEs reveal a whole new aspect of black holes that don't fit neatly into astronomers' prior understanding of the cosmic bodies. In particular, these unusual QPEs can help broaden our understanding of how these events occur. For example, there's no evidence that Ansky has shredded a star into its accretion disk, which is what researchers currently believe triggers most QPEs. Therefore, there must be another explanation for the impetus that causes the QPEs in this case. The X-ray bursts may instead come from energetic shocks in the accretion disk spurred by a small celestial object repeatedly disrupting its orbiting material, according to the paper. RELATED STORIES —Incredible photo shows supermassive black hole blowing a jet of matter into interstellar space —Black holes can destroy planets — but they can also lead us to thriving alien worlds. Here's how. —Black holes may obey the laws of physics after all, new theory suggests It's also possible that these repeated QPEs come from gravitational waves. The European Space Agency's upcoming Laser Interferometer Space Antenna (LISA), set to launch in 2035, may confirm that connection by detecting gravitational waves with greater fidelity than ever before. For now, Ansky is reshaping how we conceive of black holes. "Studying Ansky will help us to better understand black holes and how they evolve," Hernández-García said.
Yahoo
11-04-2025
- Science
- Yahoo
For the first time, astronomers watch a black hole ‘wake up' in real-time
A black hole is a terrifying concept, but the mysterious nexus of physics and space-time isn't always gobbling up matter. While famous for devouring anything and everything in its gravitational pull, black holes aren't constantly destructive. In fact, they often exhibit long periods of dormancy. Astronomers had never witnessed a black hole 'wake up' in real time—until now. Researchers have spent the past few years watching a black hole re-awaken roughly 300 million light-years away from Earth. And what they've documented challenges prevailing theories about black hole lifecycles. The groundbreaking observations are detailed in a study published on April 11 in Nature Astronomy. For decades, the supermassive black hole anchoring a galaxy known as SDSS1335+0728 in the Virgo constellation hasn't displayed much activity. But beginning in late 2019, astronomers noticed it began to emit intermittent, bright flashes of energy. They soon reclassified the galaxy's center as an active galactic nucleus nicknamed 'Ansky,' and enlisted telescopes from NASA and the ESA to help study the unexpected event. 'When we first saw Ansky light up in optical images, we triggered follow-up observations using NASA's Swift X-ray space telescope, and we checked archived data from the eROSITA X-ray telescope, but at the time we didn't see any evidence of X-ray emissions,' Paula Sánchez Sáez, a researcher at the European Southern Observatory in Germany and lead researcher of the first team to study Ansky, said in a statement. Fast forward to February 2024 when Lorena Hernández-García at Chile's Valparaiso University began detecting even more regular X-ray bursts from Ansky. The rare events allowed astronomers to once again aim their tools like the XMM-Newton X-ray space telescope and NASA's Chandra, NICER, and Swift telescopes at Ansky. Hernández-García and collaborators then determined the black hole was displaying a phenomenon known as a quasiperiodic eruption, or QPE. 'QPEs are short-lived flaring events. And this is the first time we have observed such an event in a black hole that seems to be waking up,' said Hernández-García. XMM-Newton proved particularly critical to studying Ansky's behavior, since it is the only telescope sensitive enough to capture fainter background X-ray light amid the black hole's stronger X-ray bursts. By comparing the two phases, astronomers could calculate the amount of energy released by Ansky during its more active periods. While a black hole inevitably destroys everything it captures, objects behave differently during their impending demise. A star, for example, generally stretches apart into a bright, hot, fast-spinning disc known as an accretion disc. Most astronomers have theorized that black holes generate QPEs when a comparatively small object like a star or even a smaller black hole collides with an accretion disc. In the case of Ansky, however, there isn't any evidence linking it to the death of a star. 'The bursts of X-rays from Ansky are ten times longer and ten times more luminous than what we see from a typical QPE,' said MIT PhD student and study co-author Joheen Chakraborty. 'Each of these eruptions is releasing a hundred times more energy than we have seen elsewhere. Ansky's eruptions also show the longest cadence ever observed, of about 4.5 days.' Astronomers must now consider other explanations for Ansky's remarkable behavior. One theory posits that the accretion disc could come from nearby galactic gas pulled in by the black hole instead of a star. If true, then the X-rays may originate from high energy shocks to the disc caused by a small cosmic object repeatedly passing through and disrupting orbital matter. As it stands, astronomers possess more QPE models than data from actual events. Thanks to Ansky's reawakening, that may soon change. 'We don't yet understand what causes them,' said Hernández-García. 'Studying Ansky will help us to better understand black holes and how they evolve.'
