Astronomers have used machine learning to sharpen the 2019 Event Horizon Telescope image of the black hole M87*, the first direct image of a black hole ever taken.
The first-ever photo of a supermassive black hole has gotten a "maximum resolution" makeover, thanks to artificial intelligence (AI).
The iconic 2019 image of M87*, a solar system-size black hole in the center of the Virgo galaxy cluster, was made by pooling radio light that had traveled to us across 53 million light-years of space.
Now, a new effort has used machine learning to clean the image, sharpening it to achieve the fullest resolution possible and exposing a larger and darker central region surrounded by glowing gas that astronomers have described as a "skinny donut." The researchers published the updated image April 13 in The Astrophysical Journal Letters
"With our new machine learning technique, PRIMO, we were able to achieve the maximum resolution of the current [telescope] array," lead author Lia Medeiros(opens in new tab), an astronomer at the Institute for Advanced Study in Princeton, New Jersey, said in a statement. "Since we cannot study black holes up-close, the detail of an image plays a critical role in our ability to understand its behavior. The width of the ring in the image is now smaller by about a factor of two, which will be a powerful constraint for our theoretical models and tests of gravity."
The Messier 87 black hole, which is as wide as our solar system and 6.5 billion times the mass of the sun, was imaged by the Event Horizon Telescope (EHT), an array of eight globally synchronized radio telescopes. Black holes have such a powerful gravitational pull that nothing (not even light) can escape their maws, but this doesn't mean they can't be seen. This is because active black holes are surrounded by accretion disks — vast rings of material stripped from gas clouds and stars orbiting the black holes' event horizons — that get heated to red-hot temperatures by friction, producing a faint-yet-detectable glow.
It is from these faint radio glimmers that astronomers were able to reconstruct the distant singularity as a doughnut hole surrounded by a halo of light. But gaps in the data, arising from missing jigsaw pieces of light where no radio telescope was there to receive it, left the image fuzzy and ill-defined.
To sharpen the picture, the researchers turned to a new AI technique called principal-component interferometric modeling (PRIMO), which analyzed more than 30,000 high-fidelity simulated images of black hole gas accretions to find common patterns. These patterns were then sorted by how commonly they occurred before being blended together and applied to the original image to produce a sharper estimate.
By checking the newly rendered image with EHT data and the theory on what the black hole should look like, the researchers confirmed that their image was a very close approximation of the real thing. This obviously required the big assumption that the black hole will look like we expect it to, but the researchers said the 2019 image already confirmed theoretical predictions of its broad details. This new image will enable even closer study of the extreme effects produced by the cosmic sinkholes, where our theories of gravity and quantum mechanics break down and merge, the team added.
"The 2019 image was just the beginning," Medeiros said. "If a picture is worth a thousand words, the data underlying that image have many more stories to tell. PRIMO will continue to be a critical tool in extracting such insights."
James Webb Space Telescope discovers oldest black hole in the universe — a cosmic monster 10 million times heavier than the sun
The James Webb Space Telescope has spotted the earliest known black hole in the universe, and astronomers think even earlier ones could have swarmed the young cosmos.
The James Webb Space Telescope (JWST), whose powerful cameras allow it to peer back in time to the earliest stages of the universe, discovered the supermassive black hole, which has a mass of 10 million times that of the sun, at the center of a baby galaxy 570 million years after the universe began.
The cosmic monster could be just one of countless black holes that gorged themselves to ever-larger sizes during the cosmic dawn — the period starting about 100 million years after the Big Bang when the young universe glowed for a billion years. Astronomers aren't sure why there were so many of these black holes or how they got so big. The researchers who found the latest black hole published their findings March 15 on the preprint server arXiv, but the research has not been peer-reviewed yet.
"This is the first one that we're finding at this redshift [point in time after the Big Bang], but there should be many of them," lead study author Rebecca Larson, an astrophysicist at the University of Texas at Austin, told Live Science. "We do expect that this black hole didn't just form [recently], so there should be more that are younger and existed earlier on in the universe. We're just starting to be able to study this time in cosmic history this way with the JWST, and I'm excited for us to find more of them."
Black holes are born from the collapse of giant stars and grow by ceaselessly gorging on gas, dust, stars and other black holes. For some of the gluttonous space-time ruptures, friction causes the material spiraling into their maws to heat up, and they emit light that can be detected by telescopes — turning them into so-called active galactic nuclei (AGN). The most extreme AGN are quasars, supermassive black holes that are billions of times heavier than the sun and shed their gaseous cocoons with light blasts trillions of times more luminous than the brightest stars.
Because light travels at a fixed speed through the vacuum of space, the deeper that scientists look into the universe, the more remote light they intercept and the further back in time they see. To spot the black hole, the astronomers scanned the sky with two infrared cameras — the JWST's Mid-Infrared Instrument (MIRI) and Near Infrared Camera — and used the cameras' built-in spectrographs to break down the light into its component frequencies.
By deconstructing these faint glimmers sent from the universe's earliest years, they found an unexpected spike among the frequencies contained within the light — a key sign that the hot material around a black hole was beaming out faint traces of radiation across the universe.
How black holes formed so suddenly across our young comos remains a mystery. Astronomers are still on the hunt for even younger, hypothesized "primordial" black holes, which came into being very soon after — or, according to some theories, even before — the Big Bang. But so far, they remain elusive.
There are two leading theories for how so many black holes grew so quickly after the Big Bang: that they are the remains of giant stars that formed far faster than the ones we know today, or that billowing clouds of incredibly dense gas collapsed suddenly to form the all-consuming singularities in space-time.
"The direct collapse method would have to start with a larger amount of matter in the galaxy directly collapsing into a black hole," Larson said. "It's less likely but it would take less time, and there hasn't been that much time at the point we observed it."
More likely, it is a so-called Population III Star — a category of hypothesized stars that were the first to ever exist in the universe and were made of just hydrogen and helium — that exploded and left behind a black hole around 200 million years after the Big Bang and "then accreted a lot of material pretty quickly and occasionally at a faster-than-stable rate," to swell up to the size that researchers observed, Larson explained.
The researchers will now begin working alongside the team that built MIRI to scan for an even stronger signature of the light from the distant galaxy. Those emissions could contain further clues about how the mysterious black hole formed at the galaxy's center.
Originally published on LiveScience.com.
No comments:
Post a Comment