The discovery of the galaxy HD1, located some 13.5 billion light-years away, is a significant milestone in our understanding of the early universe. The galaxy is believed to have existed only about 330 million years after the Big Bang, making it one of the earliest and most distant galaxies ever observed.
In addition to its distance, HD1 may also be harboring another surprise. It is possible that the galaxy contains Population III stars, the first stars born in the cosmos, or the earliest supermassive black hole ever found. These discoveries could provide valuable insights into the formation and evolution of the universe in its earliest days.
Further research and observations will be needed to confirm these possibilities and uncover more about the nature of HD1 and its place in the history of the universe.
Astronomers may have discovered the most distant galaxy, HD1. The findings have been presented in two papers, which were released on April 7 in The Astrophysical Journal and the Monthly Notices of the Royal Astronomical Society Letters (MNRAS). These papers provide important insights into the early universe and the formation and evolution of galaxies. Further research and observations will be needed to confirm these findings and uncover more about the nature of HD1 and its place in the history of the cosmos.
HD1 is believed to be one of the most distant galaxies ever discovered, existing only about 330 million years after the Big Bang. Its age compared to the farthest galaxy confirmed to date is not clear, as the universe’s most distant objects are constantly being discovered and studied.
HD1 is extremely bright in ultraviolet light, which is usually evidence that a galaxy is producing stars at a high rate. However, researchers quickly realized that even if HD1 was a starburst galaxy, it would be creating over 100 stars a year, which is at least ten times higher than what is expected for these types of galaxies.
As a result, the team turned to other possibilities that might explain HD1’s surplus of ultraviolet light. Further research and observations will be needed to confirm these possibilities and uncover more about the nature of HD1 and its place in the history of the universe.
Population III stars float in priмordial gas in this artist’s concept of the early uniʋerse. NASA/WMAP Science Teaм
The first stars
One possible explanation for HD1’s ultraviolet radiance is that the stars the galaxy is producing are different from the mundane stars produced in modern galaxies. In the early universe, after the Big Bang, the first stars were born from priмordial gas consisting entirely of hydrogen, helium, and a sampling of lithium and beryllium. These stars are known as Population III stars, and they were more massive, more luminous, and hotter than today’s stars. They burned out within only a few million years, and direct evidence of them has never been spotted.
The recent discovery of the earliest star, Earendel, may prove fruitful for Population III hunters if follow-up studies find the star’s composition to be entirely hydrogen and helium. While Population III stars would easily explain HD1’s brightness in the ultraviolet wavelength, they are not the only possibility. Further research and observations will be needed to confirm the nature of the stars in HD1 and the source of its ultraviolet radiance.
An artist’s concept of a galaxy in the early universe. The bright center is a quasar — highly luminous oƄjects powered Ƅy supermassiʋe black holes. ESO/M. Kornmesser
Earliest cosмic мonster
Alternatiʋely, a supermassive black hole could also explain HD1’s ultraviolet brightness. If this is the case, it would become the earliest known supermassive black hole, breaking the previous record by some 500 million years.
Supermassive black holes are believed to exist in the hearts of most galaxies, but how these monsters grew so quickly in the early universe remains a mystery. Black holes need time to accumulate enough material to grow to supermassive proportions, which is why scientists didn’t expect to see them so early in the cosmic timeline.
However, in 2017, astronomers began finding supermassive black holes within the earliest galaxies. Disks of material surrounded the black holes, and the infalling matter shone so brightly that the galaxies, despite their extreme distances, can still be seen today. It is the high-energy photons from that infalling material, violently swirled around the black hole, that may be causing HD1’s ultraviolet brightness.
A black hole in HD1 must have grown out of a massive seed at an unprecedented rate, forming a few hundred million years after the Big Bang, as explained by MNRAS co-author Avi Loeb. While such an early black hole may not answer the question of how these objects grew so big so quickly, it would narrow down how soon they appeared in the early universe.
JWST up to bat
The team spent more than 1,200 hours observing with various telescopes, including the Subaru Telescope, VISTA Telescope, UK Infrared Telescope, and Spitzer Space Telescope, to make this distant discovery. To verify HD1’s distance and further understand the nature of the object, the team plans to observe the galaxy again, this time with NASA’s James Webb Space Telescope.
Capable of peering back to the first luminous glows that emerged after the Big Bang, the James Webb Space Telescope will also be able to settle which theory explains HD1’s ultraviolet brightness. In addition, it may help find even more distant galaxies in the earliest moments of the cosmos. The observations from the James Webb Space Telescope are eagerly awaited, as they will provide significant insights into this intriguing object and the early universe.
Source: amazingastronomy.thespaceacademy.org
