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spacetimewithstuartgary · 10 months

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Never-before-seen way to annihilate a star Most stars in the Universe die in predictable ways, depending on their mass. Relatively low-mass stars like our Sun slough off their outer layers in old age and eventually fade to become white dwarf stars. More massive stars burn brighter and die sooner in cataclysmic supernova explosions, creating ultradense objects like neutron stars and black holes. If two such stellar remnants form a binary system, they also can eventually collide. New research, however, points to a long-hypothesized, but never-before-seen, fourth option. While searching for the origins of a long-duration gamma-ray burst (GRB), astronomers using the Gemini South telescope in Chile, part of the International Gemini Observatory operated by NSF’s NOIRLab, and other telescopes [1], have uncovered evidence of a demolition-derby-like collision of stars or stellar remnants in the chaotic and densely packed region near an ancient galaxy’s supermassive black hole. “These new results show that stars can meet their demise in some of the densest regions of the Universe where they can be driven to collide,” said Andrew Levan, an astronomer with Radboud University in The Netherlands and lead author of a paper appearing in the journal Nature Astronomy. “This is exciting for understanding how stars die and for answering other questions, such as what unexpected sources might create gravitational waves that we could detect on Earth.” Ancient galaxies are long past their star-forming prime and would have few, if any, remaining giant stars, the principal source of long GRBs. Their cores, however, are teeming with stars and a menagerie of ultra-dense stellar remnants, such as white dwarf stars, neutron stars, and black holes. Astronomers have long suspected that in the turbulent beehive of activity surrounding a supermassive black hole, it would only be a matter of time until two stellar objects collide to produce a GRB. Evidence for that type of merger, however, has been elusive. The first hints that such an event had occurred were seen on 19 October 2019 when NASA’s Neil Gehrels Swift Observatory detected a bright flash of gamma rays that lasted for a little more than one minute. Any GRB lasting more than two seconds is considered “long.” Such bursts typically come from the supernova death of stars at least 10 times the mass of our Sun — but not always. The researchers then used Gemini South to make long-term observations of the GRB’s fading afterglow to learn more about its origins. The observations allowed the astronomers to pinpoint the location of the GRB to a region less than 100 light-years from the nucleus of an ancient galaxy, which placed it very near the galaxy’s supermassive black hole. The researchers also found no evidence of a corresponding supernova, which would leave its imprint on the light studied by Gemini South. “Our follow-up observation told us that rather than being a massive star collapsing, the burst was most likely caused by the merger of two compact objects,” said Levan. “By pinpointing its location to the center of a previously identified ancient galaxy, we had the first tantalizing evidence of a new pathway for stars to meet their demise.” In normal galactic environments, the production of long GRBs from colliding stellar remnants such as neutron stars and black holes is thought to be vanishingly rare. The cores of ancient galaxies, however, are anything but normal and there may be a million or more stars crammed into a region just a few light-years across. Such extreme population density may be great enough that occasional stellar collisions can occur, especially under the titanic gravitational influence of a supermassive black hole, which would perturb the motions of stars and send them careening in random directions. Eventually, these wayward stars would intersect and merge, triggering a titanic explosion that could be observed from vast cosmic distances. It is possible that such events occur routinely in similarly crowded regions across the Universe but have gone unnoticed until this point. A possible reason for their obscurity is that galactic centers are brimming with dust and gas, which could obscure both the initial flash of the GRB and the resulting afterglow. This particular GRB, identified as GRB 191019A, may be a rare exception, allowing astronomers to detect the burst and study its after effects. The researchers would like to discover more of these events. Their hope is to match a GRB detection with a corresponding gravitational-wave detection, which would reveal more about their true nature and confirm their origins, even in the murkiest of environments. The Vera C. Rubin Observatory, when it comes online in 2025, will be invaluable in this kind of research. “Studying gamma-ray bursts like these is a great example of how the field is really advanced by many facilities working together, from the detection of the GRB, to the discoveries of afterglows and distances with telescopes like Gemini, through to detailed dissection of events with observations across the electromagnetic spectrum,” said Levan. “These observations add to Gemini’s rich heritage developing our understanding of stellar evolution,” says Martin Still, NSF’s program director for the International Gemini Observatory. “The time sensitive observations are a testament to Gemini’s nimble operations and sensitivity to distant, dynamic events across the Universe.” IMAGE....Astronomers studying a powerful gamma-ray burst (GRB) with the International Gemini Observatory, operated by NSF’s NOIRLab, may have observed a never-before-seen way to destroy a star. Unlike most GRBs, which are caused by exploding massive stars or the chance mergers of neutron stars, astronomers have concluded that this GRB came instead from the collision of stars or stellar remnants in the jam-packed environment surrounding a supermassive black hole at the core of an ancient galaxy. CREDIT International Gemini Observatory/NOIRLab/NSF/AURA/M. Garlick/M. Zamani

#space #science #Astronomy #physics #news #gamma ray burst #black holes #stellar evolution

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bpod-bpod · 22 days

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Mutant Gene Model

Zebrafish with a mutation in a gene called FOXE1 show hypothyroidism and cranio-facial abnormalities, features of the human genetic disorder Bamforth-Lazarus syndrome

Read the published research article here

Image from work by Sophie T Raterman and colleagues

Department of Dentistry-Orthodontics and Craniofacial Biology, Research Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, Netherlands

Image originally published with a Creative Commons Attribution – NonCommercial – NoDerivs (CC BY-NC-ND 4.0)

Published in bioRxiv, February 2024 (not peer reviewed)

You can also follow BPoD on Instagram, Twitter and Facebook

#science #biomedicine #biology #genetics #zebrafish #bamforth-lazarus syndrome

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maaarine · 7 months

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Will studying a new language interfere with any others you speak? (Shayla Love, Psyche, Sep 11 2023)

"When Julie Sedivy’s father died, she returned home to the Czech Republic and discovered another loss: Czech, her native tongue.

In her book Memory Speaks: On Losing and Reclaiming Language and Self (2021), Sedivy, a language scientist in Canada, describes her experience with language attrition – the forgetting of a language once known, even one learned long ago.

For her, language attrition felt connected to her learning English, which crowded out the Czech.

‘Like a household that welcomes a new child, a single mind can’t admit a new language without some impact on other languages already residing there,’ Sedivy wrote.

This is a frequent observation among multilinguals, that ‘Languages can co-exist, but they tussle, as do siblings, over mental resources and attention,’ as she put it. (…)

When new learning interferes with older learning, it’s called ‘retroactive interference’.

This is common when learning more than one language, says Kristin Lemhöfer, the senior author on the recent paper, and an associate professor in psycholinguistics at Radboud University in the Netherlands.

If you first learn that ‘dog’ is chien in French, and then you learn that it’s perro in Spanish, remembering un chien could become more effortful later.

One lingering question about retroactive interference is whether new learning can interrupt much older learning that’s been consolidated into long-term memory, rather than something learned more recently.

This new study showed it’s possible; Lemhöfer was surprised that learning Spanish words impacted the recall of the English that the Dutch participants had learned many years previously.

And interestingly, the experiments also revealed that interference can arise from simply learning a new language, whether or not it is used.

After seeing this interference demonstrated in the lab, Lemhöfer says it’s something that language learners should be prepared for: multilingualism may simply be taxing on the brain.

Multilinguals have been shown to take longer to find and produce a word in any of the languages they speak, and they can experience tip-of-the-tongue-states more often, she says.

Lemhöfer is German, spent a year in London, and then went to the Netherlands for her PhD – so she has plenty of firsthand experience with this phenomenon.

‘When I started to learn Dutch, my English was suddenly blocked,’ she says.

‘When I tried to speak it, a lot of Dutch words came out, which was embarrassing at times. It only disappeared once my Dutch became more stable, and I spoke more English again.’

It may not be completely avoidable, but Lemhöfer thinks that these effects can be alleviated by continuing to use the language that’s being forgotten or interfered with.

‘Even though we did not empirically test that in that study, we strongly believe that the forgetting effects we observed can be avoided by continuing to use the other language, too,’ Lemhöfer says."

#article

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victorysp · 6 months

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On October 17, 1923, the Roman Catholic University of Nijmegen, now Radboud University in Nijmegen, was founded. King Willem-Alexander attended the academic session today on the occasion of the 100th anniversary. October 17, 2023.

📷 Royal House of the Netherlands

#dutch royal family #king willem alexander

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xpoolboy · 1 year

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Hey! I'm Julia Neugarten, I am a researcher of fandom at the Radboud University Nijmegen. I'm considering writing an article about Goncharov and I was wondering whether I could cite your post that starts: "being on tumblr for the goncharov incident has made me realize how those ancient stories and myths got made up."If yes, how should I refer to you? If you don't want to be mentioned, that's also fine! Best, Julia

oh that's so cool yeah i'm down! you can call me xpoolboy, i'd love for you to link me the article once it's finished! also, i have that post edited to another image right now, if it'd be better for the citing in your article for me to edit it back just let me know!

#RESEARCHER OF FANDOM?? goddamn that's cool. anyway thanks julia #asks #bri's saves #this is so fun i love attention!!

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tastydregs · 10 months

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Eventually All Stars and Planets Will Evaporate Via Hawking Radiation

Due to Hawking radiation, black holes will eventually evaporate, but the event horizon is not as crucial as had been believed. Gravity and the curvature of spacetime cause this radiation too. This means that all large objects in the universe, like the remnants of stars, will eventually evaporate.

Using a clever combination of quantum physics and Einstein’s theory of gravity, Stephen Hawking argued that the spontaneous creation and annihilation of pairs of particles must occur near the event horizon.

Researchers at Radboud University investigated whether or not the presence of an event horizon is indeed crucial. They combined techniques from physics, astronomy and mathematics to examine what happens if such pairs of particles are created in the surroundings of black holes. The study showed that new particles can also be created far beyond this horizon.

Physical Review Letters- Gravitational Pair Production and Black Hole Evaporation

They present a new avenue to black hole evaporation using a heat-kernel approach analogous as for the Schwinger effect. Applying this method to an uncharged massless scalar field in a Schwarzschild spacetime, they show that spacetime curvature takes a similar role as the electric field strength in the Schwinger effect. They interpret the results as local pair production in a gravitational field and derive a radial production profile. The resulting emission peaks near the unstable photon orbit. Comparing the particle number and energy flux to the Hawking case, they find both effects to be of similar order. However, the pair production mechanism itself does not explicitly make use of the presence of a black hole event horizon.

Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.

Known for identifying cutting edge technologies, he is currently a Co-Founder of a startup and fundraiser for high potential early-stage companies. He is the Head of Research for Allocations for deep technology investments and an Angel Investor at Space Angels.

A frequent speaker at corporations, he has been a TEDx speaker, a Singularity University speaker and guest at numerous interviews for radio and podcasts. He is open to public speaking and advising engagements.

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forabeatofadrum · 2 years

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On a happier River fic note, I was once again thinking about my OCs for that fic (as you do) and of course it’s the classic “side character in canon, main character in my heart” thing, so here’s some random facts about the lekker met de meiden klainen groupschat ladies.

Femke Cheng

25 years old, so slightly younger than Kurt and Blaine who are 27 in the fic

her parents moved to the south of the Netherlands (aka Limburg) in the 70s or 80s so Femke is born in the Netherlands

yes she speaks Dutch with a slight southern accent and even though her accent was never really that deep, she refuses to lose it, even though she’s lived “boven de rivieren” for almost a decade

she understands Chinese and she can speak it, but she doesn’t do it a lot. (is there a name for the Dutch version of ABC aka American-Born-Chinese? DBC? Dutch-Born-Chinese?)

I honest to god have no clue what she studied at Radboud University or what she’s currently doing in Rotterdam but she is Thriving

chaotic

Bella Kim

baby

no I mean, she’s the youngest of the bunch, she’s 18

aka baby

i am now having the shocking realisation that this means she’s born in goddam 2002 and she’s younger than my younger sister what the fuck

her parents moved from Korea just before her birth

also wants to study law because she has the aspiration to change the world

she grew up in Liverpool, lived in Lancashire for a while, but moved back to Liverpool before leaving the UK to study in Rotterdam

she probably has an older sister, idk man she just gives off “youngest sibling vibes” to me for some reason

she is also fluent in Korean

Adeola Ajayi

she’s just turned 20 before the fic

born and raised in Nigeria and she moved to Rotterdam for her studies, but I also have no clue what she’s doing

she speaks Nigerian English and Yoruba

she’s probably the most levelheaded out of the three of them

[NSYNC tune] bi bi bi

her favourite colour is purple

#look LOOK river fic is back on its bullshit cause i got some shitty news about Real Blaine from Real Mercedes yesterday #and lol yeah i am still angry/sad about that #but these trivia facts have been on my mind for a while #so when i got that news and got sad about river fic it was time to break out the girls #story extras #klaine advent 2021

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fullyfundedscholarships · 5 days

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Radboud University Scholarships 2024

#FullyFundedScholarships #RadboudUniversity #RadboudUniversityScholarships #ScholarshipPositions #StudyAbroad

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xtruss · 1 month

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Frans de Waal, Biologist Who Championed Animal Intelligence and Emotion, Dies at 75

The Primatologist Found Parallels Between Human Behavior and that of Our Evolutionary Cousins.

— By Kayleigh E. Long | March 21, 2024

De Waal eats a banana at the Barcelona Zoo, while a chimpanzee looks on. Photograph By Xavier Cervera, Panos Pictures/Redux

Frans de Waal, the prolific Dutch-American primatologist and author whose research revealed the depth and breadth of emotion and intelligence in nonhuman animals, died from stomach cancer on March 14 in Stone Mountain, Georgia, according to the New York Times. He was 75.

“It’s difficult to sum up the enormity of Frans de Waal’s impact, both globally and here at Emory,” said Lynne Nygaard, chair of Emory University’s department of psychology, in a statement on the school's website. “He was an extraordinarily deep thinker who could also think broadly, making insights that cut across disciplines. He was always ready to participate in an intellectual discussion.”

De Waal’s studies of animal behaviors that were once ascribed solely to humans—fairness, empathy, altruism, reciprocity, self-recognition, conflict resolution, grief, and consolation—played a pivotal role in bringing about the acceptance of animal emotion as a valid line of scientific inquiry.

Frans de Waal holds a young chimpanzee at Burgers’ Zoo in the Netherlands, in 1979, where he began his primate studies. Photograph By Desmond Morris

Early Life

Born in the city of ‘s-Hertogenbosch, the Netherlands, in 1948, de Waal showed an early enthusiasm for animals, keeping (with varying degrees of success) a modest menagerie that included mice and jackdaws, relatives of crows. Some of the jackdaws, de Waal recounted in stories, would even fly to and from school with him each day.

After an underwhelming introduction to biology in high school, de Waal almost went on to study mathematics or physics. It was his mother who reminded him of his long-standing interest in animals, and in 1966, he began an undergraduate degree in biology at the Catholic University of Nijmegen (now the Radboud University Nijmegen) in the Netherlands.

De Waal’s entry into primate research was the result of a happy coincidence. He found biology to be somewhat dry, with its heavy focus on anatomy. The psychology department, where he spent time during his studies to earn extra money, happened to have two chimpanzees. This early exposure to primates would prove pivotal.

At a career retrospective in 2014, he regaled the audience with a tale of how the chimps would become sexually aroused when female colleagues passed the enclosure. He and a male colleague sought to test this by dressing up as women—apparently eliciting little to no interest from the male chimpanzees. It was, he conceded, an imperfectly designed experiment.

De Waal observes some of the chimpanzees he studied at Emory University’s Yerkes National Primate Research Center in 1991. Photograph By Erik S. Lesser, AP Photo

In 1977, de Waal received his doctorate in biology from Utrecht University, where he worked under professor and mentor Jan van Hooff, an expert in primate facial expressions. His dissertation looked at aggression and alliance formation in macaques.

He went on to serve as the C.H. Candler Professor in the psychology department of Emory University, in Georgia, and as the director of the Living Links Center at Emory’s Yerkes National Primate Research Center. He was elected to the American Academy of Arts and Sciences, the National Academy of Sciences, and the Royal Dutch Academy of Sciences, and occupied the role of editor-in-chief of the journal Behaviour from 2011 until 2024.

Breakthrough Research

De Waal was frustrated with what he saw as a misplaced focus on aggression in primates; he was more interested in cooperative behavior and cognition. In what became a theme throughout his career, his studies of reconciliation and conflict resolution among primates were initially controversial and challenged the prevailing orthodoxy, but as the data were confirmed his ideas went on to gain widespread acceptance.

In the field of animal emotion, de Waal made his biggest mark. The post-Darwin consensus on animal behavior steered away from anthropomorphizing, or attributing to animals any characteristics perceived as uniquely human. De Waal saw this as a form of “anthropo-denial.” In his view, the question wasn’t whether or not animals had emotions; rather, it was how to study them.

The species perhaps most closely associated with de Waal is the bonobo, a close relative of chimpanzees that he first saw at a zoo in the Netherlands. It only took a minute, he would later relate, for him to realize they were different from chimps in both vocalization and behavior. He knew immediately that he needed to study them. Colleagues at the time couldn’t understand why he would want to spend time on what were then referred to as “pygmy chimps,” often derided as “the poor man’s chimpanzee.”

But he found a home for his research at San Diego Zoo and in 1983 received a National Geographic Society grant to study the zoo’s bonobos.

His work raised the profile of bonobos, the species he dubbed the “make love, not war” primate and called “peace-loving hippies.”

He contended that science’s focus on the chimpanzee as our closest living relative made little sense, and suggested that bonobos were also genetically similar to humans, therefore equally deserving of attention.

De Waal found the establishment somewhat prudish where the subject of sex—a cherished form of recreation for the bonobo—was concerned. At a 2014 symposium celebrating his career, he joked with the audience:

“I talked openly about the sexual behavior,” he said. “At the time, American and Japanese scientists who worked on bonobos—they knew what they did, but they didn’t talk about it. They were too shy about it!” He noted that Americans would describe bonobos as “fairly affectionate. And you know, if I were affectionate like that in the streets of New York I would get arrested immediately!”

When he started to put a book on bonobos together with wildlife photographer Frans Lanting, which features explicit sexual pictures of the apes, “we had to put it in the contract with our publishers that they would not censor our pictures.” Their photo book, Bonobo: The Forgotten Ape, published in 1997. Lanting paid tribute to his colleague in an email to National Geographic in May 2022:

“Frans de Waal’s work helps us understand who we are in the context of our next of kin on the tree of life. He has a unique ability to connect the evolutionary dots for a broader audience without sacrificing the scientific principles he was equally well-versed in. He is a great storyteller and not afraid to raise questions which fuel the public conversation about the deep connections between us as humans with our nearest relatives in the great primate family we’re all part of,” Lanting said.

Legacy

Primatologist and professor of anthropology at the University of Wisconsin-Madison, Karen Strier, told National Geographic in an email that de Waal unquestionably changed the way science views (and treats) primates.

“His most influential insights, in my view, can be divided into three areas,” says Strier. The first was that “nonhuman primates are more thoughtful than we thought, in both their cognitive abilities and in their empathy and morality,” he says, spurring more ethical treatment of primates. The second: Frans’ “fine-grained observations of individuals in social groups, powerful experimental and analytical designs, and informative comparisons among closely-related species” showed the scientific community that a tremendous amount can be observed and concluded about primates through non-invasive techniques. The third, Streir says, is that “through his work we have gained new perspectives” on the evolution of our own behavior as humans.

To de Waal, the existence of emotions and behaviors such as fairness in animals was obvious. The question was simply how to quantify and qualify these traits. His approach to experiments and observation yielded hard data, bringing scientific credibility to previously elusive concepts. In 2003, de Waal and colleague Sarah Brosnan conducted experiments in which capuchin monkeys were “paid” with either cucumber pieces or much-coveted grapes in return for completing a task. Footage of the disgruntled capuchin given the inferior cucumber went on to be a viral hit, clearly demonstrating that capuchins understand the concepts of fairness and injustice.

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In 2011, de Waal and colleagues went on to prove that chimpanzees are inherently altruistic as well. When given a choice between helping themselves, or themselves and another, they will choose the latter.

He authored 16 books, which have been translated into over 20 languages and sold millions of copies worldwide. It was Chimpanzee Politics: Power and Sex Among Apes that catapulted his work into the popular imagination, drawing parallels between the behavior of our primate relatives and that of another species: human politicians.

De Waal referred to writing books as his parallel career. Inspired by ethologist and author Desmond Morris, he understood the value of popularizing science. With a flair for presenting a compelling narrative underpinned by scientific rigor, de Waal achieved the rare feat of attaining and maintaining both popular success and the respect of his scientific peers. His 2016 book Are We Smart Enough to Know How Smart Animals Are? landed on the New York Times best sellers list, and his 2019 book Mama’s Last Hug won the PEN/E.O. Wilson Literary Science Award.

“It is rare for a scientist to have such an enormous positive impact on both the academic field in which they work and the public’s perception and understanding of that field,” Joshua Plotnik, an elephant cognition expert who earned his Ph.D. under de Waal, told National Geographic by email. “Frans [was] most certainly one of those scientists.”

#Youtube #Primates #Apes 🦧 🦍#Animal 🦔 🦓 🦒 Behavior #Biologist #Biology #Chimpanzees #Bonobos

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9jacompass · 2 years

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Twente University Offers Scholarships For International Students 2023/2024-Apply Now

Twente University Masters scholarship is for students from both EU/EEA as well as non-EU/EEA countries who demonstrate strong academic abilities and are capable of enrolling in a postgraduate study in the Netherlands. Successful candidates will have the exclusive opportunity to take part in an intake for one of three honours programmes. Are you a student seeking a master’s education at one of the…

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mindblowingscience · 6 months

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Astronomers using NASA's powerful James Webb Space Telescope (JWST) just spotted tellurium, an element rarer than platinum is on Earth, in the aftermath of two dense stellar corpses about 1 billion light-years away. The findings could help researchers better understand the conditions in which precious chemical elements are created in the universe. "Just over 150 years since Dmitri Mendeleev wrote down the periodic table of elements, we are now finally in the position to start filling in those last blanks of understanding where everything was made, thanks to Webb," study lead author Andrew Levan of Radboud University in the Netherlands and lead author of the study said in a statement.

#tellurium #JWST #james webb space telescope #science #chemistry #astronomy #space #physics #stem

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spacetimewithstuartgary · 10 months

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Stellar demolition derby births powerful gamma-ray burst While searching for the origins of a powerful gamma-ray burst (GRB), an international team of astrophysicists may have stumbled upon a new way to destroy a star. Although most GRBs originate from exploding massive stars or neutron-star mergers, the researchers concluded that GRB 191019A instead came from the collision of stars or stellar remnants in the jam-packed environment surrounding a supermassive black hole at the core of an ancient galaxy. The demolition derby-like environment points to a long-hypothesized—but never-before-seen—way to demolish a star and generate a GRB. The study was published in the journal Nature Astronomy. Led by Radboud University in the Netherlands, the research team included astronomers from Northwestern University. "For every hundred events that fit into the traditional classification scheme of gamma-ray bursts, there is at least one oddball that throws us for a loop," said Northwestern astrophysicist and study co-author Wen-fai Fong, "However, it is these oddballs that tell us the most about the spectacular diversity of explosions that the universe is capable of." "The discovery of these extraordinary phenomena within dense stellar systems, especially those encircling supermassive black holes at the cores of galaxies, is undeniably exciting," said Northwestern astrophysicist and study co-author Giacomo Fragione. "This remarkable discovery grants us a tantalizing glimpse into the intricate dynamics at work within these cosmic environments, establishing them as factories of events that would otherwise be deemed impossible." Fong is an assistant professor of physics and astronomy at Northwestern's Weinberg College of Arts and Sciences and a member of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). Fragione is a research assistant professor in CIERA. Other Northwestern co-authors include Anya Nugent and Jillian Rastinejad—both Ph.D. students in astronomy and members of Fong's research group. Most stars die, according to their mass, in one of three predictable ways. When relatively low-mass stars like our sun reach old age, they shed their outer layers, eventually fading to become white dwarf stars. More massive stars, on the other hand, burn brighter and explode faster in cataclysmic supernovae explosions, creating ultra-dense objects like neutron stars and black holes. The third scenario occurs when two such stellar remnants form a binary system and eventually collide. But the new study finds there might be a fourth option. "Our results show that stars can meet their demise in some of the densest regions of the universe, where they can be driven to collide," said lead author Andrew Levan, an astronomer with Radboud University. "This is exciting for understanding how stars die and for answering other questions, such as what unexpected sources might create gravitational waves that we could detect on Earth." Long past their star-forming prime, ancient galaxies have few, if any, remaining massive stars. Their cores, however, teem with stars and a menagerie of ultra-dense stellar remnants, such as white dwarfs, neutron stars and black holes. Astronomers have long suspected that in the turbulent beehive of activity surrounding a supermassive black hole, it only would be a matter of time before two stellar objects collided to produce a GRB. But evidence for that type of merger has remained elusive. On Oct. 19, 2019, astronomers glimpsed the first hints of such an event when NASA's Neil Gehrels Swift Observatory detected a bright flash of gamma rays that lasted a little over one minute. Any GRB lasting longer than two seconds is considered "long." Such bursts typically come from the collapse of stars at least 10 times the mass of our sun. The researchers then used the Gemini South telescope in Chile—part of the International Gemini Observatory operated by the National Science Foundation's NOIRLab—to make long-term observations of the GRB's fading afterglow. These observations enabled the astronomers to pinpoint the location of the GRB to a region less than 100 light-years from the nucleus of an ancient galaxy—very near the galaxy's supermassive black hole. Curiously, the researchers also found no evidence of a corresponding supernova, which would leave its imprint on the light captured by Gemini South. "The lack of a supernova accompanying the long GRB 191019A tells us that this burst is not a typical massive star collapse," said Rastinejad, who performed calculations to ensure a supernova was not hiding within the data. "The location of GRB 191019A, embedded in the nucleus of the host galaxy, teases a predicted but not yet evidenced theory for how gravitational-wave emitting sources might form." In typical galactic environments, the production of long GRBs from colliding stellar remnants, such as neutron stars and black holes, is incredibly rare. The cores of ancient galaxies, however, are anything but typical, and there may be a million or more stars crammed into a region just a few light-years across. Such extreme population density may be great enough that occasional stellar collisions can occur, especially under the titanic gravitational influence of a supermassive black hole, which would perturb the motions of stars and send them careening in random directions. Eventually, these wayward stars would intersect and merge, triggering a titanic explosion that could be observed from vast cosmic distances. "This event confounds almost every expectation we have for the environments of short and long GRBs," said Nugent, who performed crucial modeling of the host galaxy. "While long GRBs are never found in galaxies as old and dead as GRB 191019A's host, short GRBs, with their merger origins, have not been observed to be so connected to their hosts' nuclei. The discovery of this event in the core of its old, quiescent galaxy opens the door to promising new avenues for the formation of binary systems that have rarely been observed before." It is possible that such events occur routinely in similarly crowded regions across the universe but have gone unnoticed until this point. A possible reason for their obscurity is that galactic centers are brimming with dust and gas, which could obscure both the initial flash of the GRB and the resulting afterglow. GRB 191019A may be a rare exception, allowing astronomers to detect the burst and study its aftereffects. "While this event is the first of its kind to be discovered, it's possible there are more out there that are hidden by the large amounts of dust close to their galaxies," Fong said. "Indeed, if this long-duration event came from merging compact objects, it contributes to the growing population of GRBs that defies our traditional classifications." By working to discover more of these events, the researchers hope to match a GRB detection with a corresponding gravitational-wave detection, which would reveal more about their true nature and confirm their origins—even in the murkiest of environments. The Vera C. Rubin Observatory, when it comes online in 2025, will be invaluable in this kind of research. The study, "A long-duration gamma-ray burst of dynamical origin from the nucleus of an ancient galaxy," is published in Nature Astronomy. IMAGE....Artistic illustration of a gamma-ray burst. Credit: International Gemini Observatory/NOIRLab/NSF/AURA/M. Garlick/M. Zamani

#space #science #Astronomy #physics #news #black holes #gamma ray burst

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