Astronomers discover 83 supermassive black holes 13 billion light-years away

Agencies
March 15, 2019

Washington, Mar 15: Astronomers have discovered 83 quasars powered by supermassive black holes 13 billion light-years away from the Earth, from a time when the universe was less than 10 per cent of its present age.

“It is remarkable that such massive dense objects were able to form so soon after the Big Bang,” said Michael Strauss, a professor at Princeton University in the US.

“Understanding how black holes can form in the early universe, and just how common they are, is a challenge for our cosmological models,” Strauss said in a statement.

This finding, published in The Astrophysical Journal, increases the number of black holes known at that epoch  considerably, and reveals, for the first time, how common they are early in the universe’s history.

In addition, it provides new insight into the effect of black holes on the physical state of gas in the early universe in its first billion years.

Supermassive black holes, found at the centers of galaxies, can be millions or even billions of times more massive than the Sun.

While they are prevalent today, it is unclear when they first formed, and how many existed in the distant early universe.

A supermassive black hole becomes visible when gas accretes onto it, causing it to shine as a “quasar.” Previous studies have been sensitive only to the very rare, most luminous quasars, and thus the most massive black holes.

The new discoveries probe the population of fainter quasars, powered by black holes with masses comparable to most black holes seen in the present-day universe.

The team used data taken with “Hyper Suprime-Cam” (HSC) instrument, mounted on the Subaru Telescope of the National Astronomical Observatory of Japan, which is located on the summit of Maunakea in Hawaii.

The researchers selected distant quasar candidates from the sensitive HSC survey data.

They then carried out an intensive observational campaign to obtain spectra of those candidates, using three telescopes: the Subaru Telescope; the Gran Telescopio Canarias on the island of La Palma in the Canaries, Spain; and the Gemini South Telescope in Chile.

The survey revealed 83 previously unknown very distant quasars.

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ABDUL AZIZ SHE…
 - 
Saturday, 16 Mar 2019

SUBHAANALLAH

 

 
ALLAH ALMIGHTY CREATED EVERTHING  INCLUDING WHOLE UNIVERSE AND WHAT IS IN IT,

HUMAN BEING CANNOT REACH TO UNDERSTAND IT,  HUMAN LIFE NOT SUFFEICENT TO REACH AND KNOW EVERYTHING.

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Agencies
June 10,2020

US dictionary Merriam-Webster will update the meaning of the word "racism" after being contacted by a Missouri black woman, who claimed the current definition fell short of including the systematic oppression of people of colour, according to media reports.

"A revision to the entry for racism is now being drafted to be added to the dictionary soon, and we are also planning to revise the entries of other words that are related to racism or have racial connotations," according to a statement of the 189-year-old dictionary shared by Kennedy Mitchum, a recent graduate of Drake University in Iowa, on her Facebook.

Mitchum, 22, emailed the dictionary last month, following the death of African American George Floyd in the custody of four Minneapolis police officers, Xinhua news agency reported.

"I kept having to tell them that definition is not representative of what is actually happening in the world," Mitchum told CNN. "The way that racism occurs in real life is not just prejudice, it's the systemic racism that is happening for a lot of black Americans."

Merriam-Webster's first definition of racism is "a belief that race is the primary determinant of human traits and capacities and that racial differences produce an inherent superiority of a particular race."

"It's not just disliking someone because of their race," Mitchum wrote in a Facebook post on Friday. "This current fight we are in is evidence of that, lives are at stake because of the systems of oppression that go hand-in-hand with racism."

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News Network
February 18,2020

Beijing, Feb 18: Police in China have arrested a prominent activist who had been a fugitive for weeks and criticised President Xi Jinping's handling of the coronavirus epidemic while in hiding, a rights group said Tuesday.

Anti-corruption activist Xu Zhiyong was arrested on Saturday after being on the run since December, according to Amnesty International.

China's ruling Communist Party has severely curtailed civil liberties since Xi took power in 2012, rounding up rights lawyers, labour activists and even Marxist students.

The death this month of a whistleblowing doctor who was reprimanded by police for raising the alarm about the deadly new virus before dying of it himself triggered rare calls for political reform and freedom of speech.

The "Chinese government's battle against the coronavirus has in no way diverted it from its ongoing general campaign to crush all dissenting voices," said Patrick Poon, China researcher at Amnesty International, in an emailed statement.

Another source, who spoke to news agency on the condition of anonymity, said Xu had been arrested in the southern city of Guangzhou.

Guangzhou police did not respond to requests for comment.

Xu went into hiding after authorities broke up a December gathering of intellectuals discussing political reform in the eastern coastal city of Xiamen in Fujian province, prior to the coronavirus crisis.

Over a dozen lawyers and activists were detained or disappeared after the Xiamen gathering, according to rights groups -- and Xu's detention appears linked to his presence at the meeting, explained Poon.

But while on the run, Xu continued to post information on Twitter about rights issues.

On February 4 Xu released an article calling on Xi to step down and criticised his leadership across a range of issues including the US-China trade war, Hong Kong's pro-democracy protests and the coronavirus epidemic, which has now killed nearly 1,900 people.

"Medical supplies are tight, hospitals are filled with patients, and a large number of infected people have no way to be diagnosed," he wrote. "It's a mess."

"The coronavirus outbreak shows just how important values like freedom of expression and transparency are -- the exact values that Xu has long advocated," Yaqiu Wang, China researcher at Human Rights Watch, told news agency.

But the disappearance of Xu illustrates how the Chinese state "persists in its old ways" by "silencing its critics", she said.

Xu -- who founded a movement calling for greater transparency among high-ranking officials -- previously served a four-year prison sentence from 2013 to 2017 for organising an "illegal gathering".

"That he was a fugitive for so many days while continuing to speak out, that in itself was... a kind of challenge to (Chinese authorities)," said Hua Ze, a long-time friend of Xu who told AFP she lost contact with the Chinese activist on Saturday morning.

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News Network
June 17,2020

New Delhi, Jun 17: With an increase of 10,974 new cases and 2,003 deaths in the last 24 hours, India's COVID-19 count reached 3,54,065 on Wednesday while the toll due to the virus stands at 11,903.

This includes 1,55,227 active cases and 1,86,935 cured, discharged and migrated patients, according to the Union Health Ministry.

While the spike in the number of cases has stayed below the 11-thousand mark, the death toll has increased manifold today as compared to the 380 death reported on Tuesday.

Maharashtra with 1,13,445 cases continues to be the worst-affected state in the country with 50,057 active cases while 57,851 patients have been cured and discharged in the state so far. The toll due to COVID-19 has crossed the five thousand mark and reached 5,537 in the state.

It is followed by Tamil Nadu with 48,019 and the national capital with 44,688 confirmed cases.

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