The bright red object in the early universe turned out to be the most distant galaxy ever discovered.
As astronomers have discovered, this galaxy already existed 330 million years after the Big Bang.
Its dim light, which is stretched by the expansion of the universe, took 13.5 billion light years to reach Earth.
The discoverers called the galaxy HD1 and it is a mystery. Scientists do not yet fully know what this galaxy looks like: a star-forming galaxy in which new stars are actively born, or a quasar, or active, huge supermassive black hole at its center.
If it is a quasar, an increase to the supermassive size of a black hole so shortly after the Big Bang would call into question current patterns of black hole formation and evolution.
“Answering questions about the nature of a source so far away is a big challenge. It is almost as if, far from the shore, with a flag hoisted on a ship shrouded in heavy fog, he guessed the country of his registration. One can see certain colors and shapes of the flag, but not the whole flag. “Ultimately, it’s a long way to go to analyze and rule out unbelievable scenarios,” said Fabio Pacucci, an astrophysicist at the Harvard-Smithsonian Institution.
Finding objects in the early universe is difficult. The brightest objects in the entire cosmos, even quasars, are obscured in the far reaches of space-time, beyond the point where our most powerful telescopes can capture light.
HD1 was discovered as part of a program designed to search for galaxies in the early universe. The program used the four most powerful optical and infrared telescopes: the Subaru Telescope, the VISTA Telescope, the United Kingdom Infrared Telescope, and the Spitzer Space Telescope. They made observations at 1200 hours long, observing the cosmic light to find signs of light in the early universe.
“It turned out to be a very difficult job to find HD1 among more than 700,000 objects. Its red color matched remarkably well with the expected characteristics of a galaxy 13.5 billion light-years away. “I was even shocked when I found him,” said Uchi Harikane, an astronomer at the University of Tokyo.
The color red is known as redshift and arises when a light source moves away from us. This in turn causes the light waves from the source to increase towards the red ends of the electromagnetic spectrum; This is why it is called the redshift.
As the universe expands, other galaxies appear reddened; The farther the distance in space-time, the greater the redshift. Through this effect, astronomers calculate how many yards of light reach us.
However, the light of HD1 is confusing. It is extremely bright at ultraviolet wavelengths, indicating that strong energy processes were taking place in this galaxy. For the first time, researchers thought it was a normal star-forming activity – rather than calculating how many stars it would take to emit that amount of light.
The number turned out to be extremely high, with more than a hundred stars a year. This is 10 times more than we would expect in an early universe galaxy. This issue can be resolved if the stars born then were not the same as we see today.
“The very first population of stars formed in the universe was much more massive, brighter and hotter than today’s stars,” Pakuchi said.
According to him, if we consider that the stars formed in HD1 are the first stars, or population III, then its characteristics can be more easily explained. Moreover, the stars of Population III can emit more ultraviolet light than usual, which explains the extreme ultraviolet brightness of HD1.
The second option is that this galaxy was a quasar. The term is fully pronounced as “quasi-stellar radio source” – the incredibly dazzling result of an active galactic nucleus, when the supermassive black hole there so greedily absorbs matter that the light produced at that time shines all over the universe.
Researchers estimate that in order to produce observable light, a supermassive black hole must be about 100 times more massive than our Sun.
A huge birthplace of early galaxies has been discovered – # 1tv Science
Similar: Discovered in the early universe of galaxies …
Such a mass even seriously questions current models of black hole growth. For the early world it’s too big, too early.
“Just a few hundred years after the Big Bang, the HD1’s black hole had to grow from a massive seed to an unprecedented rate. “Once again, nature seems to have a much richer imagination than we do,” said Avi Loeb, an astrophysicist at the Harvard-Smithsonian Astrophysics Center.
A team of researchers hopes that future observations made by the James Webb Space Telescope will shed light on the nature of this distant, mysterious light from the dawn of time. The main purpose of the James Webb is to explore the early world.
The studies will be published in The Astrophysical Journal and Monthly Notices of the Royal Astronomical Society, and will be available on the arXiv server