Latest news with #RagadeepikaPucha
Yahoo
27-02-2025
- Science
- Yahoo
Scientists Just Found 300 of Some of the Rarest Black Holes in the Universe
Intermediate-mass black holes—somewhere between stellar-mass and supermassive—are the rarest type of black hole in the universe. 300 of these elusive black holes were recently observed by NSF NOIRLab's DESI (Dark Energy Spectroscopic Instrument). While some are the active galactic nuclei of dwarf galaxies, most are thought to have been the seeds of what are now supermassive black holes. Some black holes are supermassive beasts up to tens of billions of times the mass of our Sun. Then, there are stellar-mass black holes, which top out at a few solar masses. So... what fills the void in between? One of the rarest types of black holes in the universe are intermediate-mass black holes (IMBHs). Sometimes referred to as 'missing link' black holes, these cosmic gaping maws—which can be anywhere from about 100 to 100,000 solar masses in size—have proved difficult to find. Recently, however, NSF NOIRLab's Dark Energy Spectroscopic Instrument (DESI) has been able to detect 300 more of them. DESI also detected active black holes in many dwarf galaxies, which are exactly what they sound like—rather small black holes with only a handful of stars (if you could call thousands to several billion a handful) scattered around. Only between 100 and 150 IMBHs were known, until now. Using the new data, a research team led by Ragadeepika Pucha from the University of Utah wanted to find out what intermediate-mass black holes can tell us about black hole formation. Supermassive black holes (SMBHs), which lurk in the centers of enormous galaxies like our own, destroy and consume so much material and expel so much energy that they are fairly obvious. Both the Milky Way's supermassive black hole (Sagittarius A*) and the monster at the heart of the galaxy M83 were able to be imaged because of the extreme brightness of their accretion disks. Black holes of lower mass, however, don't devour nearly as much. As a result, they are harder to make out—though, it does help if a smaller black hole is actively feeding at the time of observation, as the energy given off as it rips stars apart makes it easier to spot. 'When a black hole at the center of a galaxy starts feeding, it unleashes a tremendous amount of energy into its surroundings, transforming into what we call an active galactic nucleus,' Pucha said in a press release. 'This dramatic activity serves as a beacon, allowing us to identify hidden black holes in these small galaxies.' While Pucha's team was expecting most of the newly discovered IMBHs to be the active galactic nuclei (AGNs) of dwarf galaxies, that turned out not to be the case. Only 70 intermediate-mass black holes were associated with dwarf galaxies, judging by where their energy emissions came from. This is a surprise, considering how closely IMBHs are associated with dwarf galaxies (Given their size, it makes sense that their AGNs would be black holes of intermediate mass). But surprises are like candy to scientists, as they offer opportunities to ask questions that the experts may never have even thought to pose. After finding out the remaining IMBHs were not in dwarf galaxies, the researchers want to continue investigating these mysterious objects. They think that at least some of these black holes could be supermassive black hole seeds that might help explain the origins of the SMBHs we see in the universe today. SMBHs form by accretion, meaning that they accumulate more and more mass over time—either through standard 'eating' or through mergers with other black holes—until they reach a size that can hold a galaxy together. But these gigantic black holes had to start somewhere, and one of the leading theories for what their seeds may have been is IMBHs. Because the IMBHs observed by DESI are so distant, the team was able to see them as they were billions and billions of years ago, since that is how long their light took to reach Earth. As a result, it is possible that some of these objects have evolved into SMBHs by now, and studying their origins could tell us a lot about their evolution. 'As we cannot directly observe their formation with our current telescopes, we focus on their imprints on the local universe,' Pucha and her team said in a study recently posted to the preprint server arXiv. 'Most of these early black holes grow via accretion and mergers into the SMBHs we see today.' DESI, which will be scanning the sky for five more years, is expected to observe around 40 million galaxies and quasars during its lifespan. If it's already found 300 examples of one of the universe's greatest mysteries, who knows what else it will find. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Yahoo
25-02-2025
- Science
- Yahoo
U of U researchers discover more than 2,500 black holes
SALT LAKE CITY (ABC4) — A team of scientists at the University of Utah have identified thousands of new dwarf galaxies hosting black holes at their center. The marks the largest sample of such galaxies ever compiled and will expand scientists' understanding of the number of black holes that exist in the universe while also setting the stage for more research on the formation of the universe's first black holes. According to Ragadeepika Pucha, who led the research, the discovery was made possible by a massive, four-meter-tall telescope at in Tuscon, Arizona. This effort to curb climate change could do more harm than good, U of U research shows 'Detecting black holes in dwarf galaxies is very hard because dwarf galaxies are very faint,' Pucha told The team's early data included an unprecedented 410,000 galaxies captured in one image series, 115,000 of which were small galaxies known as dwarf galaxies. According to Pucha, when a black hole begins feeding, it releases a large amount of energy, which scientists can detect. 'This dramatic activity serves as a beacon, allowing us to identify hidden black holes in these small galaxies,' she said. 'People are going to freak out': U of U researchers make massive black hole discovery 'In the dwarf galaxies, we found about 2,500 of these active black holes, which is the largest sample to date…and triples the amount of galaxies that have been found before,' Pucha told adding that the team's findings indicate that many black holes have gone undetected in past research. from the team's findings were collected through an instrument known as a Dark Energy Spectroscopic Instrument (DESI), which measures dark energy in the cosmos by taking optical spectra, or images, of millions of galaxies and quasars, before constructing a 3D map spanning up to 11 billion light-years away. The telescope is the most powerful of its kind in the world Pucha said. 'This is just one science that can be done…there is much more that is being done and will be done using this data. We just have to wait for the results [from] the amazing telescope that it is,' she said. Copyright 2025 Nexstar Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Yahoo
19-02-2025
- Science
- Yahoo
Hundreds of Black Hole 'Missing Links' May Have Been Discovered in New Survey
A survey to reveal the unseen majority of the Universe has just turned up a treasure trove of black holes that may help solve one of the biggest mysteries of the cosmos. Lurking at the centers of dwarf galaxies speckled throughout space, astronomers have found 2,444 active black holes, slurping up matter from material around them. And, even more amazingly, 298 of these appear to be that elusive beast, the black hole of intermediate mass – long considered a missing link between stellar-mass black holes and supermassive behemoths. This is nearly triple the number of previously known intermediate mass black hole (IMBH) candidates, representing the largest haul to date – a discovery that has huge implications for our understanding of how black holes get to masses equivalent to millions or billions of Suns. "The statistical sample of dwarf active galactic nucleus candidates," the researchers write, "will be invaluable for addressing several key questions related to galaxy evolution on the smallest scales, including accretion modes in low-mass galaxies and the co-evolution of galaxies and their central black holes." Supermassive black holes can be found at the centers of all large, well-formed galaxies. They're the nuclei around which galaxies revolve, and their masses are tremendous. The supermassive black hole at the center of the Milky Way, for example, is 4.3 million times the mass of the Sun. That's on the low end of the mass scale; these beasts can reach masses that are tens of billions of solar masses. We don't know how these black holes grow so big. Current theoretical models propose that one pathway is growth via accretion and mergers, growing with their galaxies; but our current technology doesn't allow us to see the "seeds" of these black holes in the early Universe. They are simply too small and too dim. What we can do, however, is look for equivalent small galaxies with small black holes in the local Universe. And, using the Dark Energy Spectroscopic Instrument (DESI), an instrument designed to survey the Universe, this is what a team led by astronomer Ragadeepika Pucha of the University of Utah has done. In its first year of operations, the terrestrial observatory collected observations of 114,496 dwarf galaxies – in high enough detail that the astronomers could zoom in and study their centers closely, looking for signs of black holes that are actively feeding, known as an active galactic nucleus. "When a black hole at the center of a galaxy starts feeding, it unleashes a tremendous amount of energy into its surroundings, transforming into what we call an active galactic nucleus," Pucha says. "This dramatic activity serves as a beacon, allowing us to identify hidden black holes in these small galaxies." The number of active galactic nuclei they identified in dwarf galaxies – 2,444 – represented 2.1 percent of the total dwarf galaxy sample. That's a huge number, nearly four times higher than the fraction found in previous surveys. This means that there are likely way more low-mass supermassive black holes out there than we had been able to account for based on previous data. The observations were so detailed that the team was able to use them to try to calculate the masses of the black holes they were looking at. From these calculations, the researchers identified nearly 300 IMBH candidates, sitting between around 100 and 100,000 times the mass of the Sun. Black holes in this mass regime are highly sought by astronomers, because they're shockingly rare. We know that a massive, dying star can produce a black hole, but the upper mass for these single-star objects is a few tens of solar masses. What we don't have is a good sample of objects that explain how these (relatively) tiny black holes can grow to supermassive size. We do know that black holes can merge to produce bigger black holes. A really solid sampling of IMBH in that mass gap would go a long way towards helping solve at least part of the mystery, giving us a pile of evidence that the process can, eventually, produce some absolute black hole units. The team's new haul may just give us this sampling. Previously, only around 100 to 150 IMBH candidates had been identified. The work of Pucha and her colleagues gives us 151 confident candidates, and 147 tentative candidates. At the very least, it seems to have more than doubled the previous catalogue. And already it's toppling our expectations. Only 70 of the IMBH candidates they found were in dwarf galaxies. The rest were hanging out in normal galaxies. This suggests that the coevolution of black holes and galaxies may not be as simple as we thought. And that's just from DESI's early data. There is so much more out there waiting to be discovered, and so many questions yet to answer. "For example, is there any relationship between the mechanisms of black hole formation and the types of galaxies they inhabit?" Pucha says. "Our wealth of new candidates will help us delve deeper into these mysteries, enriching our understanding of black holes and their pivotal role in galaxy evolution." The research has been published in The Astrophysical Journal. 'Missing' Planet to Join a Rare Cosmic Lineup This Week 'Dead' Galaxy Cluster Is Making Stars Again And Astronomers Don't Know Why Odds of 'City Killer' Asteroid Impact in 2032 Now Even Higher, Says NASA
