Astronomers detect oldest black hole ever observed
New Delhi, Jan 18: Researchers have discovered the oldest black hole ever observed, dating from the dawn of the universe, and found that it is 'eating' its host galaxy to death.
The research, published in the journal Nature, used the the James Webb Space Telescope (JWST) to detect the black hole, which dates from 400 million years after the Big Bang, more than 13 billion years ago.
That this surprisingly massive black hole—a few million times the mass of our sun—even exists so early in the universe challenges the assumptions about how black holes form and grow, the researchers said.
Astronomers believe that the supermassive black holes found at the centre of galaxies like the Milky Way grew to their current size over billions of years.
However, the size of this newly-discovered black hole suggests that they might form in other ways.
According to standard models, supermassive black holes form from the remnants of dead stars, which collapse and may form a black hole about a hundred times the mass of the Sun.
If it grew in an expected way, this newly detected black hole would take about a billion years to grow to its observed size. However, the universe was not yet a billion years old when this black hole was detected.
"It's very early in the universe to see a black hole this massive, so we've got to consider other ways they might form," said lead author Roberto Maiolino, Professor at Cambridge University, UK.
"Very early galaxies were extremely gas-rich, so they would have been like a buffet for black holes," Maiolino said.
Like all black holes, this young one is devouring material from its host galaxy to fuel its growth. Yet, this ancient black hole is found to gobble matter much more vigorously than its siblings at later epochs, the researchers said.
The young host galaxy, called GN-z11, glows from such an energetic black hole at its center. Black holes cannot be directly observed, but instead they are detected by the tell-tale glow of a swirling accretion disk, which forms near the edges of a black hole, they said.
The gas in the accretion disk becomes extremely hot and starts to glow and radiate energy in the ultraviolet range. This strong glow is how astronomers are able to detect black holes.
GN-z11 is a compact galaxy, about one hundred times smaller than the Milky Way, but the black hole is likely harming its development, according to the researchers.
When black holes consume too much gas, it pushes the gas away like an ultra-fast wind. This 'wind' could stop the process of star formation, slowly killing the galaxy, but it will also kill the black hole itself, as it would also cut off the black hole's source of 'food', they said.
"It's a new era: the giant leap in sensitivity, especially in the infrared, is like upgrading from Galileo's telescope to a modern telescope overnight," Maiolino said.
The sensitivity of JWST means that even older black holes may be found in the coming months and years, he added.
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England sticking with Key, McCullum and Stokes despite Ashes humbling
London (AP): England is not sacking anybody following the 4-1 Ashes loss in Australia.
A review of the tour by the England and Wales Cricket Board, announced within hours of the final match in January, was concluded on Monday. Firing people would “be the easy thing to do,” ECB chief executive Richard Gould said but he insisted, "This is not the time to throw everything out."
Managing director Rob Key, coach Brendon McCullum and captain Ben Stokes kept their jobs after the best England side to go to Australia in 14 years lost the Ashes in 11 days with two games to spare.
“Moving people on can sometimes be the easy thing to do. That's not the route that we're going to take,” Gould said. “I've seen the driving ambition and determination that we're lucky enough to have within our leadership group to take the lessons from the Ashes and move forward.”
Gould previously was the chief executive of Bristol City soccer club and said the ECB would not follow the same route as soccer's hire-and-fire culture.
“Cricket is a very unique sport in that it takes a team of leadership ... it's not like football where there's a single point of failure or success with a manager," he said. He added the ECB would not “select or deselect management based on a popularity campaign.”
The main criticisms of England's tour were poor preparation, player misbehavior, and selection mistakes.
At a press conference at Lord's, Gould and Key said McCullum and Stokes have not had a “bust up,” they did not want McCullum to “completely change” but “to evolve,” the behavior of some players was “unprofessional,” there will be more consequences for underperforming, and a commitment to “better long-term planning” ahead of major test series.
Some changes were already implemented for the Twenty20 World Cup, where England reached the semifinals. Gould implied that performance saved McCullum.
Key acknowledged that England supporters would be disappointed to see the management team go unpunished.
“I know people want punishment and that people then should be sacked for that,” Key said. “That doesn't mean we don't feel like we've gone through some serious pain: Brendon, myself, Ben. It's been as tough a time as I think I've had.”
