An international team of astrophysicists led by Radboud University in the Netherlands has discovered a new mechanism for destroying stars and creating gamma-ray bursts (GRPs). (Art illustration of a gamma-ray burst.) Credit: International Gemini Laboratory/NOIRLab/NSF/AURA/M. Pundu/M. Jamani

Astrophysicists have discovered a new mechanism for stellar extinction and gamma-ray burst formation, which originates from stellar collisions in dense environments near supermassive black holes in ancient galaxies. This discovery was published Natural AstronomyImproves our understanding of stellar deaths and may point to previously unknown sources[{” attribute=””>gravitational waves.

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 on June 22 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.”

https://www.youtube.com/watch?v=YsbpXBisBgk
This artist’s impression illustrates how astronomers study a powerful gamma-ray burst (GRB) with the NSF-operated Gemini South telescope.[{” attribute=””>NOIRLab, may have detected 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.

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.

“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.”
— Anya Nugent, Ph.D. student in astronomy

“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.

Reference: “A long-duration gamma-ray burst of dynamical origin from the nucleus of an ancient galaxy” by Andrew J. Levan, Daniele B. Malesani, Benjamin P. Gompertz, Anya E. Nugent, Matt Nicholl, Samantha R. Oates, Daniel A. Perley, Jillian Rastinejad, Brian D. Metzger, Steve Schulze, Elizabeth R. Stanway, Anne Inkenhaag, Tayyaba Zafar, J. Feliciano Agüí Fernández, Ashley A. Chrimes, Kornpob Bhirombhakdi, Antonio de Ugarte Postigo, Wen-fai Fong, Andrew S. Fruchter, Giacomo Fragione, Johan P. U. Fynbo, Nicola Gaspari, Kasper E. Heintz, Jens Hjorth, Pall Jakobsson, Peter G. Jonker, Gavin P. Lamb, Ilya Mandel, Soheb Mandhai, Maria E. Ravasio, Jesper Sollerman and Nial R. Tanvir, 22 June 2023, Nature Astronomy.
DOI: 10.1038/s41550-023-01998-8

SpaceX will send another batch of its Starlink satellites into space today (June 23), and you can watch them all live for free.

SpaceX plans to launch 56 Starlink satellites aboard a Falcon 9 rocket at 9:56 a.m. EDT (1356 GMT). As livestream information becomes available, Space.com will post it here for you to view.

WASHINGTON (AP) — Interest in impeaching President Joe BidenHard-right House Republicans forced a vote on Thursday that sent the matter to congressional committees, clearly proving a challenge to Speaker Kevin McCarthy. The majority is the controlling face of the party.

A single legislator, Rep. The ability of Rep. Lauren Bobert, R-Colo., to push through an impeachment resolution caught Republicans off guard this week with unwritten action. Many saw this as a political distraction from other priorities.

The action accuses Biden of “numerous crimes and misdemeanors” in connection with his handling of the US border with Mexico.

Bobert, backed by his allies, a lone lawmaker in the 435-member House, showed how the chamber’s rules could be used to force a snap vote on such a grave constitutional matter. A 219-208 party-line vote sent the impeachment to committees for possible consideration like the rest of the bill.

“The council is taking historic action,” Boebert said during the debate, though the committees are under no obligation to act.

The episode underscored the stranglehold the House conservative side exerted over McCarthy for several days. It empowers a small group of Republicans to use rare tactics to exert power over its majority, albeit without rewards.

Conservatives are still gearing up for such actions: The process Boebert used to force the issue was another hard-right conservative, Rep. Rep. Anna Paulina Luna, R-Fla., was sent Wednesday to force a separate vote to censure Democratic Rep. Adam Schiff Regarding his investigations into Donald Trump’s ties to Russia.

“There will be no end to this,” Schiff told The Associated Press and others in the Capitol Wednesday amid a no-confidence vote.

“Kevin McCarthy has no control over his conference,” Schiff said. “Fierce competition now drives the House of Representatives, and it certainly does terrible damage to the institution.”

During Thursday’s debate, Republicans were repeatedly admonished to tone down their comments.

Democrats have argued that the case against Biden mocks the seriousness of the impeachment and is an attempt to distract from twice-impeached Donald Trump, the former GOP leader now accused of hoarding classified documents under the Espionage Act.

“Today they dishonor this House and dishonor themselves by bringing this ridiculous impeachment resolution to the floor,” said Rep. Jim McGovern of Massachusetts, the top Democrat on the House Rules Committee, who Trump recommended his allies push for it.

“This body has become a place where serious, exotic and nuanced issues are discussed passionately, and not as important,” McGovern said. “In short, the Republican Party is a joke.”

The vote ended McCarthy’s days of maneuvering to quell an uproar within his party over a roll call that was not taken by many.

A snap vote to impeach Biden would have been politically difficult for GOP lawmakers and an embarrassing scenario for McCarthy, splitting his party.. In a private meeting on Wednesday, McCarthy encouraged lawmakers to consider the traditional process of bringing forward such a resulting piece of legislation.

Ultimately, McCarthy negotiated with Bobert and sent the Biden impeachment resolution to the Judiciary and Homeland Security committees for reconsideration.

“I think it’s best for everybody,” McCarthy told reporters Wednesday.

But conservatives vowed more such votes.

“We’re just getting started,” said Rep. Chip Roy of Texas, an influential member of the House Freedom Caucus.

Conservatives are lining up other such votes — to fire Homeland Security Secretary Alejandro Mayorkas, for example, and to censure Democratic Rep. Benny Thompson, who chaired the committee investigating the Jan. 6, 2021, attack on the Capitol.

Part of their effort is to divert control of the House from traditional centers of power, including the Speaker’s office.

“This is what we’ve been talking about,” said Rep. Matt Gates of Florida, a leader of conservative efforts to block McCarthy from becoming speaker. They were brokers who had more say in the House process.

Boebert said he would bring his resolution back to the floor “every day for the rest of my time here in Congress” to force a House vote on Biden’s impeachment if the committees move slowly.

Rank-and-file Republicans were furious at being forced to vote on a resolution to impeach Biden. They resented a lawmaker jumping the line of priorities.

In a fiery exchange heard on the House floor, hard-right Rep. Marjorie Taylor Green slams Bobert for taking the Biden charge on herself. Green has his own articles of impeachment against the president.

Greene later confirmed the exchange and said of Bobert, “She has a great talent and skill that most people here don’t like her.”

Bobert declined to comment on the conversation, saying only that it was “not middle school.”

“I want the anger directed at Ms. Bobert to be directed at the president and his policies,” said Rep. R-Va., a member of the Independent Caucus. Bob Good said.

Getz noted that when Democrats controlled the House, impeachment efforts by renegade lawmakers failed and the former president was eventually impeached before a majority supported the effort.

“It helped the Democrats build momentum, so this could be our version,” Gates said.

Trump has been impeached twice — on corruption and obstruction charges for withholding military aid to Ukraine while seeking political dirt on Biden, and later on Jan. 6, 2021, for inciting a riot in the Capitol that tried to overturn Biden’s election. Both times Trump was acquitted by the Senate.

___

Associated Press writers Farnoosh Amiri and Stephen Groves contributed to this report.

WASHINGTON (AP) — President Joe Biden’s comments about Chinese President Xi Jinping as a “dictator” and China as a country with “real economic problems” drew swift condemnation from China on Wednesday, opening a fresh rift after the two countries agreed to temporary measures. Need to confirm the relationship.

In Beijing, Foreign Ministry spokesman Mao Ning condemned Biden’s unusually pointed comments as “very absurd and irresponsible.”

The spat of words comes after Foreign Secretary Anthony Blinken visited Beijing On Monday, it sought to break the ice in relations that have hit a historic low. While both sides saw the talks as constructive, they did not produce significant progress beyond an agreement to return to a broader agenda of cooperation and competition.

China’s swift response to Biden, who is known for unscripted remarks outside of his administration’s policies, raises questions about whether his comments will undo the limited progress made in Blingen’s carefully crafted trip or whether both sides will move forward.

Biden’s characterization of China comes as the campaign for next year’s presidential election has already begun, with Republicans accusing him of being weak on China.

Biden was also preparing to welcome Indian Prime Minister Narendra Modi A lavish state visit to Washington on Wednesday evening, where a central theme will be a shared wariness of China.

At a fundraiser in California on Tuesday night, Biden referred to what the U.S. said was a Chinese spy balloon that flew over two weeks in January and February. The balloon’s surprise appearance in American skies shook relationships and changed the American people.

Speaking to wealthy donors at an event for his 2024 re-election campaign, Biden portrayed Xi as out of touch and embarrassed, which ended with the Air Force shooting down a balloon over the East Coast.

“The reason Xi Jinping was so upset when I shot down that balloon with two boxcars full of spy equipment is because he didn’t know it was there,” Biden told the crowd.

“No, I’m serious,” he added. “It was a great embarrassment to the dictators who did not know what had happened.”

Biden also downplayed trade competition with China, which is the world’s second-largest economy after the US but is struggling to emerge from Covid-era financial problems.

“I promise not to worry about China. Worry about China, but don’t worry about China,” Biden said. “I mean really. China has real economic problems.

Biden’s comments came hours after he called on both countries to push back on the balloon incident, calling it “a chapter that needs to be closed” in an interview with MSNBC.

In Beijing on Wednesday, Mao told reporters that Biden’s comments “are completely contrary to the facts and seriously violate diplomatic ethics, and seriously violate China’s political dignity.”

“This is a blatant political provocation,” Mao said.

Mao reiterated China’s version of the balloon episode, saying the balloon was for meteorological research and was accidentally diverted.

Administration officials signaled Wednesday that Biden did not intend to retract his comments.

Biden and Blinken “will continue to manage this relationship responsibly and maintain an open line of communication with the PRC,” State Department spokesman Vedant Patel told reporters, using the acronym for the People’s Republic of China.

“But, of course, that doesn’t mean we won’t be open and honest about our differences,” Patel said, including differences in the global competition between democracies and autocracies.

US-China tensions have risen over the years as competition over trade and global influence has developed. Repeated flare-ups have helped heighten tensions, including the balloon, US tariffs, economic sanctions on China and self-ruled Taiwan.

The U.S. is pressing China to embrace direct communication between Biden, Xi and other senior U.S. and Chinese military and civilian leaders as a channel to defuse tensions and prevent incidents from escalating into open hostilities.

Despite the administration’s diplomatic efforts to smooth ties, analysts point to Republican political pressure, and Biden appears to be going off-script to continue criticizing Xi.

Bonnie Glaser, Asia director of America’s George Marshall Fund, pointed Wednesday to the state of Biden’s State of the Union address in February after the balloon flight, when Republican lawmakers in the audience shouted him down about China and other issues. Waving a finger in the air, Biden shouted, “Name me the world leader to switch places with Xi Jinping! I have a name! Name me one! “

As for Biden, “He’s getting a lot of criticism from the right. He doesn’t want to see China soft. He sees Xi Jinping as a dictator,” Glaser said.

“He’s not very good … at distinguishing between what to say in public and what to say in private,” Glazer said. “And the relationship pays a price for that. There’s no doubt about that,” he said.

Xi may have been upset by claims he was not fully informed about the balloon incident, said Steve Chang, director of the China Institute at the University of London’s School of Oriental and African Studies and a longtime observer of Chinese politics.

“My sense is that Xi does not want to overdo it and put the relationship back on ice,” Chang said in an email.

Initial Republican response to Biden’s comments was one of approval. “It’s a perfect description of their system of government,” said Sen., the top Republican on the Senate Intelligence Committee. Marco Rubio said.

While Xi presides over a country formally named the People’s Republic of China, he is head of state, head of the military and head of the ruling Communist Party, whose terms of office pose no challenge to his authority.

In California, Biden told donors that Xi “wants to re-engage.”

Blinken “went in there … did a good job and it just takes time,” he said.

___

Associated Press writer Seung Min Kim contributed to this report.

More on Titanic Sub

SHANGHAI, June 20 (Reuters) – Alibaba Group ( 9988.HK ) said on Tuesday its CEO and Chairman Daniel Zhang would step down to focus on its cloud division. into six business units.

Zhang has been working in three roles simultaneously since December, when he took over as head of the cloud unit after a shutdown described as its “prolonged large-scale failure” for more than a decade.

The CEO role will be handed over to Eddie Yongming Wu, head of Alibaba’s Taobao and Tmall Group, while executive vice president Joseph Tsai Zhang will take over as chairman.

Both appointments will be effective Sept. 10, Alibaba said.

“Hiring Daniel to focus on Running Cloud really shows the confidence and trust he has in taking a very expensive business and fitting it into the age of artificial intelligence (AI) that runs alongside it,” he said. Brian Wong is a former Alibaba employee and author of “The Tao of Alibaba.”

“The idea or expectation that one person can manage the cloud, the crown jewel of the business, and manage the entire Alibaba Group at the same time is an unreasonable expectation.”

The surprise restructuring comes after a tumultuous two years that have seen Alibaba heavily targeted by increased regulatory scrutiny and after the group announced in March that it would be reorganized into six units, each with their own boards and CEOs.

Its China-facing e-commerce division, which includes the Taobao and Tmall marketplaces, will be wholly owned by Alibaba, but the other five units will be spun off, with Alibaba aiming to complete a public listing of its cloud unit in May. Within the next 12 months.

Zhang, in a memo to employees seen by Reuters, said the cloud spin-off was approaching a critical stage and the time was right to devote his attention to the business.

“From a corporate governance perspective, as Cloud Intelligence Group moves down the path to becoming an independent public company, there needs to be a clear separation between the board and the management team,” he said.

“It would be inappropriate for me to continue to serve as chairman and CEO of both companies simultaneously during the spin-off process.”

Analysts have estimated the value of the cloud unit at between $41 billion and $60 billion, but said the reams of data it oversees could put it in the cross hairs of regulators at home and abroad.

Singles Day

Zhang, a former accountant, joined Alibaba in 2007 and is known as the architect behind the company’s annual flagship “Singles Day” shopping festival. He has served as CEO since 2015 and took the helm in 2019, succeeding Alibaba co-founder Jack Ma in both roles.

Alibaba thanked Zhang for his “extraordinary leadership in navigating the unprecedented uncertainty that has affected the company’s business over the past few years.”

Alibaba’s Hong Kong-listed shares fell 1.5% after the announcement, in line with a 1.6% drop in the benchmark index (.HSI), as analysts see the restructuring in line with the previously announced overall restructuring.

“Under the new structure, the group will play a smaller role in setting strategies for the six business groups, so promoting Alibaba founders Joe and Eddie as chairman and CEO will help ensure a smooth leadership transition and maintain culture,” the Shanghai-based Independent reported. Eric Chen, publishing analyst at SmartKarma, told Reuters.

Wu, who co-founded Alibaba with Ma and Tsai more than two decades ago, will continue to serve as chairman of Taobao and Tmall Group, Alibaba said. His previous roles include Chief Technology Officer of Alipay and Head of Alibaba Health.

Wu’s promotion to CEO “signals a natural transition and the unchanging importance of e-commerce in the company’s roadmap,” said Jacob Cook, co-founder and CEO of Beijing-based e-commerce consultancy WPIC Marketing + Technologies.

Cook said he doesn’t see the leadership changes as signaling a major strategic shift within Alibaba, adding that the individuals are Ma’s co-founders and close associates.

“If anything, it emphasizes the importance of AI in the company’s focus, while underscoring that e-commerce is a core business unit.”

Competition

Ma, China’s top entrepreneur, has been out of the public eye since late 2020 after a speech criticizing Chinese regulation that is widely seen as precipitating a subsequent crackdown.

Ma left mainland China in late 2021 – appearing in photos in Japan, Spain, Australia and Thailand – and returned in March, a day before Alibaba announced its restructuring. He did not make any public comments during that period.

Last week, Alibaba chairman J. Michael Evans said Ma remains Alibaba’s largest shareholder and has a strong interest in the company. He said Ma teaches at a university in Tokyo and spends a lot of time in China.

On Monday, Chinese tech news agency Latepost, Ma convened a meeting with leaders of Taobao and Tmall Group, where he highlighted fierce competition and discussed the need to focus on users, the Internet and Taobao — whose merchants are mostly individuals or small businesses. Be relevant.

Alibaba did not respond to a Reuters request for comment on the LatePost report, which cited company sources.

Reporting by Abhinaya Vijayaraghavan in Bangalore and Brenda Go in Shanghai; Additional reporting by Scott Murdoch in Sydney and Anne Marie Rowntree and Josh Yeh in Hong Kong; Editing by Muralikumar Anantharaman and Christopher Cushing

Our Standards: Thomson Reuters Trust Principles.