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Scientists find an exotic black hole deemed a ‘needle in a haystack’

"This one differs from all other known black holes in that it is 'X-ray quiet' "

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Scientists find an exotic black hole deemed a ‘needle in a haystack’
GNN Media: Representational Photo

Paris: Astronomers have spotted in a galaxy adjacent to our Milky Way what they are calling a cosmic “needle in a haystack” – a black hole that not only is classified as dormant but appears to have been born without the explosion of a dying star.

Researchers said on Monday this one differs from all other known black holes in that it is “X-ray quiet” – not emitting powerful X-ray radiation indicative of gobbling up nearby material with its strong gravitational pull – and that it was not born in a stellar blast called a supernova.

This one, with a mass at least nine times greater than our sun, was detected in the Tarantula Nebula region of the Large Magellanic Cloud galaxy and is located about 160,000 light years from Earth. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).

An extremely luminous and hot blue star with a mass about 25 times that of the sun orbits with this black hole in a stellar marriage. This so-called binary system is named VFTS 243. The researchers believe the companion star eventually also will become a black hole and could merge with the other one.

Dormant black holes, thought to be relatively common, are hard to detect because they interact very little with their surroundings. Numerous prior proposed candidates have been debunked with further study, including by members of the team that uncovered this one.

“The challenge is finding those objects,” said Tomer Shenar, a research fellow in astronomy at Amsterdam University, lead author of the study published in the journal Nature Astronomy. “We identified a needle in a haystack.”

“It’s the first object of its kind discovered after astronomers have been searching for decades,” said astronomer and study co-author Kareem El-Badry of the Harvard & Smithsonian Center for Astrophysics.

The researchers used six years of observations from the European Southern Observatory’s Chile-based Very Large Telescope.

There are different categories of black holes. The smallest, like the newly detected ones, are so-called stellar-mass black holes formed by the collapse of massive individual stars at the ends of their life cycles. There also are intermediate-mass black holes as well as the enormous supermassive black holes residing at the centre of most galaxies.

“Black holes are intrinsically dark objects. They do not emit any light. Therefore, in order to detect a black hole, we usually look at binary systems in which we see one luminous star moving around a second, not-detected object,” said study co-author Julia Bodensteiner, a postdoctoral research fellow at the European Southern Observatory in Munich.

It is typically assumed that the collapse of massive stars into black holes is associated with a powerful supernova explosion. In this case, a star perhaps 20 times our sun’s mass blew some of its material into space in its death throes, then collapsed in on itself without an explosion.

The shape of its orbit with its companion offers evidence for the lack of an explosion.

“The orbit of the system is almost perfectly circular,” Shenar said.

Had a supernova occurred, the blast’s force would have kicked the newly formed black hole in a random direction and yielded an elliptical rather than circular orbit, Shenar added.

Black holes can be mercilessly ravenous, guzzling any material – gas, dust and stars – wandering within their gravitational pull.

“Black holes can only be mercilessly ravenous if there is something close enough to them that they can devour. Usually, we detect them if they are receiving material from a companion star, a process we call accretion,” Bodensteiner said.

Shenar added, “In so-called dormant black hole systems, the companion is far enough away that the material does not accumulate around the black hole to heat up and emit X-rays. Instead, it is immediately swallowed by the black hole.”

“It’s the first object of its kind discovered after astronomers have been searching for decades,” said astronomer and study co-author Kareem El-Badry of the Harvard & Smithsonian Center for Astrophysics.

The researchers used six years of observations from the European Southern Observatory’s Chile-based Very Large Telescope.

There are different categories of black holes. The smallest, like the newly detected ones, are so-called stellar-mass black holes formed by the collapse of massive individual stars at the ends of their life cycles. There also are intermediate-mass black holes as well as the enormous supermassive black holes residing at the centre of most galaxies.

“Black holes are intrinsically dark objects. They do not emit any light. Therefore, in order to detect a black hole, we usually look at binary systems in which we see one luminous star moving around a second, not-detected object,” said study co-author Julia Bodensteiner, a postdoctoral research fellow at the European Southern Observatory in Munich.

It is typically assumed that the collapse of massive stars into black holes is associated with a powerful supernova explosion. In this case, a star perhaps 20 times our sun’s mass blew some of its material into space in its death throes, then collapsed in on itself without an explosion.

The shape of its orbit with its companion offers evidence for the lack of an explosion.

“The orbit of the system is almost perfectly circular,” Shenar said.

Had a supernova occurred, the blast’s force would have kicked the newly formed black hole in a random direction and yielded an elliptical rather than circular orbit, Shenar added.

Black holes can be mercilessly ravenous, guzzling any material – gas, dust and stars – wandering within their gravitational pull.

“Black holes can only be mercilessly ravenous if there is something close enough to them that they can devour. Usually, we detect them if they are receiving material from a companion star, a process we call accretion,” Bodensteiner said.

Shenar added, “In so-called dormant black hole systems, the companion is far enough away that the material does not accumulate around the black hole to heat up and emit X-rays. Instead, it is immediately swallowed by the black hole.”

SOURCE: Reuters

World

Taiwan's fighter jets roar into sky in face of Chinese war games

Defence ministry spokesperson Sun Li-fang said this was a good chance for Taiwan's forces to hone their skills

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Taiwan's fighter jets roar into sky in face of Chinese war games

Taiwanese F-16 fighters roared into the night sky on Wednesday in a show of force in front of the media, demonstrating the military's determination to defend the democratically governed island in the face of days of Chinese war games.

China, which claims Taiwan as its territory, has been carrying out military exercises around the island after a visit earlier this month by U.S. House of Representatives Speaker Nancy Pelosi, who was followed by five U.S. lawmakers on Sunday and Monday. read more

Pelosi's visit infuriated China, which responded with test launches of ballistic missiles over Taipei for the first time, and sending warships and fighter jets close to Taiwan, though the scale of the activities has now greatly reduced.

On a government-organised trip to the key Hualien air base on Taiwan's mountainous east coast, the first to a military facility since the Chinese exercises began, reporters watched ground crew demonstrate how they rapidly upload weapons onto F-16s, including Boeing Co's (BA.N) Harpoon anti-ship missiles.

Defence ministry spokesperson Sun Li-fang told reporters at the base that while they condemned China's actions, this was a good chance for Taiwan's forces to hone their skills.

"We will seize this opportunity to test all the training we normally do, and through this improve our current methods and raise our combat effectiveness," he said.

"The Republic of China's forces are confident, capable, and determined to defend the safety of the Republic of China," Sun added, using Taiwan's formal name.

While Taiwanese fighters, including Hualien's F-16s, have been repeatedly scrambling since early this month, the ministry has stressed Taiwan's "calm" response and there have been no clashes.

"I won't say there's a lot of change but our frequency to scramble is higher and the tension is higher," said F-16 pilot Django Lin.

Taiwan President Tsai Ing-wen has said they are not seeking to provoke or escalate tensions.

The Hualien base, which has hangers cut out of the side of a mountain, has two pilots on duty at any one time sitting in their flight suits and able to be in the air within six minutes.

The fighters on display were the Lockheed Martin Corp (LMT.N) F-16V, Taiwan's most up-to-date combat jet.

Taiwan has been converting 141 F-16A/B jets into the F-16V type, and has additionally ordered 66 new F-16Vs, which have new avionics, weapons and radar systems to better face down the Chinese air force, including its J-20 stealth fighters.

The F-16Vs can also carry Raytheon Technologies Corp's (RTX.N) advanced AIM-9X Sidewinder air-to-air missiles.

Taiwan's government says that as the People's Republic of China has never ruled the island, it has no right to claim it or decide its future, which can only be set by Taiwan's people.

SOURCE: REUTERS

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Relief operations for flood affectees in full swing by PAF in South Punjab Region

Basic food items and commodities were distributed amongst the needy families

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Relief operations for flood affectees in full swing by PAF in South Punjab Region

Rawalpindi: Relief operations for the flood affectees are in full swing by Pakistan Air Force (PAF) in South Punjab Region.

According to a press release, food and medical facilities are being provided round the clock to the affected families by the relief teams of PAF.

12155 pounds of basic food items and commodities were distributed amongst the needy families. Moreover, 939 patients were also attended by the paramedical team of Pakistan Air Force.

The recent floods have caused devastation in the low-lying areas of South Punjab Region, badly damaging the villages and infrastructure.

Despite inclement weather conditions throughout the country, especially in flood stricken areas, PAF personnel are working hard to provide humanitarian assistance to flood affectees.

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World

10 including prominent cleric killed in bombing at Kabul mosque

There were fears the casualty numbers could rise further.

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10 including prominent cleric killed in bombing at Kabul mosque

A bombing at a mosque in the Afghan capital of Kabul during evening prayers on Wednesday killed at least 10 people, including a prominent cleric, and wounded at least 27, an eyewitness and police said.

There was no immediate claim of responsibility for the attack, the latest to strike the country in the year since the Taliban seized power. Several children were reported to be among the wounded.

The Islamic State group’s local affiliate has stepped up attacks targeting the Taliban and civilians since the former insurgents’ takeover last August as U.S. and NATO troops were in the final stages of their withdrawal from the country. Last week, the IS claimed responsibility for killing a prominent Taliban cleric at his religious center in Kabul.

According to the eyewitness, a resident of the city’s Kher Khanna neighborhood where the Siddiquiya Mosque was targeted, the explosion was carried out by a suicide bomber. The slain cleric was Mullah Amir Mohammad Kabuli, the eyewitness said, speaking on condition of anonymity because he was not authorized to talk to the media. 
 
He added that more than 30 other people were wounded. The Italian Emergency hospital in Kabul said that at least 27 wounded civilians, including five children, were brought there from the site of the bomb blast.

There were fears the casualty numbers could rise further.

Khalid Zadran, the Taliban-appointed spokesman for the Kabul police chief, confirmed an explosion inside a mosque in northern Kabul but would not provide a casualty toll or a breakdown of the dead and wounded.

Taliban spokesman Zabihullah Mujahid also condemned the explosion and vowed that the “perpetrators of such crimes will soon be brought to justice and will be punished.”

A U.S.-led invasion toppled the previous Taliban government, which had hosted al-Qaida leader Osama bin Laden in Afghanistan, following the Sept. 11, 2001 terrorist attacks in the United States.

Since regaining power, the former insurgents have faced a crippling economic crisis as the international community, which does not recognize the Taliban government, froze funding to the country.

Separately, the Taliban confirmed on Wednesday that they had captured and killed Mehdi Mujahid in western Herat province as he was trying to cross the border into Iran.

Mujahid was a former Taliban commander in the district of Balkhab in northern Sar-e-Pul province, and the only member of the minority Shiite Hazara community among the Taliban ranks.

Mujahid had turned against the Taliban over the past year, after opposing decisions made by Taliban leaders in Kabul.

SOURCE: AP NEWS

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