For the First Time Astronomers Watch a Black Hole 'Wake Up' in Real-Time

Black holes "often exhibit long periods of dormancy," writes Popular Science, adding that astronomers had never witnessed a black hole "wake up" in real time. "Until now..." In February of 2024 X-ray bursts were spotted coming out of a black hole named Ansky by Lorena Hernández-García at Chile's Valparaiso University, according to the article. And what astronomers have now seen "challenges prevailing theories about black hole lifecycles." Hernández-García and collaborators then determined the black hole was displaying a phenomenon known as a quasiperiodic eruption, or QPE [a short-lived flaring event...] 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. It's detailed in a study published on April 11 in Nature Astronomy.... Meanwhile, scientists "have uncovered the strongest evidence yet for the existence of elusive intermediate-mass black holes," reports SciTechDaily. And there's more black hole news from RockDoctor (Slashdot reader #15,477): Given the recent work on galaxy-centre Super-Massive Black Holes (SMBHs), you may be surprised to learn that the only Stellar-Mass Black Holes (SMBHs ... uh, "BHs") identified to-date have been by their gravitational waves, as they merge with another BH or a neutron star. But the long-running OGLE (Optical Gravitational Lensing Experiment) project (1992 — present) has recently confirmed that it has detected an isolated BH not orbiting another bright object, or "swallowing" much of anything... In this case, 16 other telescopes performed sensitive astrometry (position measurement) over 11 years including the Hubble Space Telescope (HST). These multiple measurements plot an ellipse on the sky, mirroring the movement of the Earth around it's orbit — parallax. Which means this is a relatively close object (1520 parsecs / ~5000 light years).... And there is no sign of a third light emitting body nearby, which means this is an isolated black hole, not orbiting any other body (or, indeed, with any other [small] star orbiting it). Read more of this story at Slashdot.

Apr 12, 2025 - 20:47

For the First Time Astronomers Watch a Black Hole 'Wake Up' in Real-Time

Black holes "often exhibit long periods of dormancy," writes Popular Science, adding that astronomers had never witnessed a black hole "wake up" in real time. "Until now..." In February of 2024 X-ray bursts were spotted coming out of a black hole named Ansky by Lorena Hernández-García at Chile's Valparaiso University, according to the article. And what astronomers have now seen "challenges prevailing theories about black hole lifecycles." Hernández-García and collaborators then determined the black hole was displaying a phenomenon known as a quasiperiodic eruption, or QPE [a short-lived flaring event...] 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. It's detailed in a study published on April 11 in Nature Astronomy.... Meanwhile, scientists "have uncovered the strongest evidence yet for the existence of elusive intermediate-mass black holes," reports SciTechDaily. And there's more black hole news from RockDoctor (Slashdot reader #15,477): Given the recent work on galaxy-centre Super-Massive Black Holes (SMBHs), you may be surprised to learn that the only Stellar-Mass Black Holes (SMBHs ... uh, "BHs") identified to-date have been by their gravitational waves, as they merge with another BH or a neutron star. But the long-running OGLE (Optical Gravitational Lensing Experiment) project (1992 — present) has recently confirmed that it has detected an isolated BH not orbiting another bright object, or "swallowing" much of anything... In this case, 16 other telescopes performed sensitive astrometry (position measurement) over 11 years including the Hubble Space Telescope (HST). These multiple measurements plot an ellipse on the sky, mirroring the movement of the Earth around it's orbit — parallax. Which means this is a relatively close object (1520 parsecs / ~5000 light years).... And there is no sign of a third light emitting body nearby, which means this is an isolated black hole, not orbiting any other body (or, indeed, with any other [small] star orbiting it).