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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News Network
June 12,2020

Jun 12: The global number of COVID-19 cases has increased to over 7.5 million, while the death toll was nearing 421,000, according to the Johns Hopkins University.

As of Friday morning, the overall number of cases stood at 7,500,777, while the deaths increased to 420,993, the University's Center for Systems Science and Engineering (CSSE) revealed in its latest update.

The US continues with the world's highest number of confirmed cases and deaths at 2,022,488 and 113,803, respectively, according to the CSSE.

In terms of cases, Brazil comes in the second place with 802,828 infections.

This was followed by Russia (501,800), the UK (292,860), India (286,605), Spain (242,707), Italy (236,142), Peru (214,788), France (192,493), Germany (186,691), Iran (180,156), Turkey (174,023), Chile (154,092), Mexico (133,974), Pakistan (125,933) and Saudi Arabia (116,021), the CSSE figures showed.

Regarding fatalities, the UK continues in the second position after the US with 41,364 COVID-19 deaths, which also accounts for the highest number of fatalities in Europe.

The other countries with over 10,000 deaths are Brazil (40,919), Italy (34,167), France (29,349), Spain (27,136) and Mexico (15,944).

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Agencies
January 16,2020

New Delhi, Jan 16: United Forum of Bank Unions has decided to observe a two-day strike on January 31 and February 1, demanding early wage revision settlement which has been due since November 1, 2017, said the All India Bank Employees Association.

Union Finance Minister Nirmala Sitharaman will present her second Union Budget on February 1.

Banks will also hold a strike on March 11, 12 and 13. Also, an indefinite strike will be held from April 1.

General Secretary, All India Bank Officers' Confederation West Bengal Sanjay Das has stated that the nationwide strike has been called over several demands.

"The demands include--wage revision settlement at 20 per cent hike on payslip components with adequate loading thereof and scrapping off New Pension Scheme (NPS)," said Das.

There are several demands to hold the strike including the merger of special allowance with basic pay, updation of pension, improvement in the family pension system, five-day banking, allocation of staff welfare fund based on operating profits and exemption from income tax on retiral benefits without a ceiling.

"Other demands include-- a uniform definition of business hours, lunch hour etc in the branches, introduction of leave bank, defined working hours for the officers and equal wage for equal work for the contract employee," said Das.

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Agencies
July 2,2020

Leiden, Jul 2: Astronomers have discovered a luminous galaxy caught in the act of reionizing its surrounding gas only 800 million years after the Big Bang.

The research, led by Romain Meyer, PhD student at UCL in London, UK, has been presented at the virtual annual meeting of the European Astronomical Society (EAS).

Studying the first galaxies that formed 13 billion years ago is essential to understanding our cosmic origins. One of the current hot topics in extragalactic astronomy is 'cosmic reionization,' the process in which the intergalactic gas was ionized (atoms stripped of their electrons).

Cosmic reionization is similar to an unsolved murder: We have clear evidence for it, but who did it, how and when? We now have strong evidence that hydrogen reionization was completed about 13 billion years ago, in the first billion years of the universe, with bubbles of ionized gas slowly growing and overlapping.

The objects capable of creating such ionized hydrogen bubbles have however remained mysterious until now: the discovery of a luminous galaxy in which 60-100 percent of ionizing photons escape, is likely responsible for ionizing its local bubble. This suggests the case is closer to being solved.

The two main suspects for cosmic reionization are usually 1) a population of numerous faint galaxies leaking ~10 percent of their energetic photons, and 2) an 'oligarchy' of luminous galaxies with a much larger percentage (>50 percent) of photons escaping each galaxy.

In either case, these first galaxies were very different from those today: galaxies in the local universe are very inefficient leakers, with only <2-3 percent of ionizing photons escaping their host. To understand which galaxies governed cosmic reionization, astronomers must measure the so-called escape fractions of galaxies in the reionization era.

The detection of light from excited hydrogen atoms (the so-called Lyman-alpha line) can be used to infer the fraction of escaping photons. On the one hand, such detections are rare because reionization-era galaxies are surrounded by neutral gas which absorbs that signature hydrogen emission.

On the other hand, if this hydrogen signal is detected it represents a 'smoking gun' for a large ionized bubble, meaning we have caught a galaxy reionizing its surroundings. The size of the bubble and the galaxy's luminosity determines whether it is solely responsible for creating this ionized bubble or if unseen accomplices are necessary.

The discovery of a luminous galaxy 800 million years after the Big Bang supports the scenario where an 'oligarchy' of bright leakers emits most of the ionizing photons.

"It is the first time we can point to an object responsible for creating an ionized bubble, without the need for a contribution from unseen galaxies.

Additional observations with the upcoming James Webb Space Telescope will enable us to study further what is likely one of the best suspects for the unsolved case of cosmic reionization," said Meyer.

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