For the First Time Astronomers Watch a Black Hole 'Wake Up' in Real-Time (popsci.com) 18
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).
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).
"In Real-Time" ?? (Score:2)
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Hmmm. Not by my definition.
Good point, I can never decide which of my eyes is centered at zero time, I’m always a few nanoseconds in the past.
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For observers in general (i.e, not strictly the same) reference frames, there is no such thing as "simultaneity".
From one view point, at one between-frame relative velocity, two events can appear to be simultaneous. But from any other viewpoint (or reference frame, or most combinations of both differences) those two events would not appear to be simultaneous.
If you don't have infinite speed of information transmission, you can't have simultaneity. SorryNotSorr
*taps mic* (Score:2)
Re:*taps Rujiel* (Score:2)
you may be surprised to learn (Score:4, Insightful)
"you may be surprised to learn that the only Stellar-Mass Black Holes identified to-date have been by their gravitational waves, as they merge with another BH or a neutron star."
I would be very surprised by that, since the first black hole we saw (Cygnus X1) was identified long before we had gravitational wave detectors.
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Cyg-X1's mass of ~22 Solar masses and a maximum size of 300km for any component of the radiating source is hard to reconcile with a natural object other than a BH. But around a dozen neutron stars in close orbits, with intermittent consumption of material by one or other NS is th
Privacy? Fourth Amendment? (Score:2)
What does a black hole have to do for some privacy around here?
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Black hole singularities (regions of unimpeded collapse, the fall apart of physics determinism) are separate things to event horizons. The Cosmic Censorship Hypothesis requires there to be an event horizon to isolate the singularity from the regions of space time which we inhabit, so physicists don't have an urgent need to worry about what really happens at a singularity ; but it is a hypothesis, which
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Nobody is suggesting that the BH isn't decently clothed, hiding it's singularity [wikipedia.org] behind an event horizon.
Black hole singularities (regions of unimpeded collapse, the fall apart of physics determinism) are separate things to event horizons. The Cosmic Censorship Hypothesis requires there to be an event horizon to isolate the singularity from the regions of space time which we inhabit, so physicists don't have an urgent need to worry about what really happens at a singularity ; but it is a hypothesis, which TTBOMK hasn't even had a probing thought experiment described. Au contraire, some trouble-makers have proposed theoretical scenarios whereby the CCH could be violated. (Spinning a highly-charged BH so fast that frame dragging would make the EH move at superluminal speeds, or something like that.) Nobody has (yet, TTBOMK) pointed at something on the sky and said "naked singularity!" It would be exciting if someone did, because it would allow us to probe some really extreme physics.
Avi Loeb's ears have pricked up.
Psst: Hey, buddy. We are the singularity. Keep it to yourself. People will freak the hell out if they know.
Yaawwwwn, I want a coffee, it's been a long snooze (Score:1)