Researchers believe they have discovered the farthest astronomical object ever detected. Existing only around 330 million years after the Big Bang and at a distance of 13.5 billion light-years, a galaxy known as HD1 has been dubbed not only as the most distant galaxy but also the universe's new farthest object.
The findings were published in The Astrophysical Journal (ApJ) and Monthly Notices of the Royal Astronomical Society Letters (MNRAS) on Thursday, April 7.
Most Distant Galaxy Spotted by Telescopes
The farthest distant galaxy observed to date has been detected as a bright red object in the early Universe. Named HD1 by the discoverers, the suspected galaxy is estimated to be 13.5 billion light-years away, which is 100 million light-years farther away than the existing farthest galaxy, GN-z11.
Astronomers spotted HD1 during 1,200 hours of observation with the Subaru Telescope, VISTA Telescope, United Kingdom Infrared Telescope (UKIRT), and Spitzer Space Telescope. The Atacama Large Millimeter/submillimeter Array (ALMA) was used to corroborate the distance. The team will soon observe HD1 with NASA's powerful James Webb Space Telescope to verify their initial calculations.
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As reported by Sciencealert, the red color is referred to as redshift, and it occurs when a light source moves away from an observer. It is called redshifting because this causes the wavelength of the light coming from that source to increase towards the redder end of the electromagnetic spectrum. The higher the redshift, the greater the distance in space-time.
However, the light from HD1 looks confusing as it is extremely bright in ultraviolet wavelengths.
Why Does HD1 Shine in Ultraviolet Light?
HD1 shines brightly in ultraviolet light, indicating that the most distant galaxy is teeming with activity, and is normally evidence that a galaxy is producing stars at a high rate.
Researchers propose two new explanations for the extraordinary energy emitted by the galaxy. First, it could possess a supermassive black hole 100 million times the mass of the sun at its core, making it the oldest black hole ever discovered. Second, HD1 could be home to some of the universe's very first stars, which astronomers have yet to detect, Space.com reported.
The very first population of stars that formed in the universe were bigger, brighter, and hotter than modern stars, according to Fabio Pacucci, co-author of the research announcing the discovery and an astronomer at the Harvard-Smithsonian Center for Astrophysics.
Experts believed that these stars, known as Population III stars, emit far more ultraviolet radiation than ordinary stars, which could explain HD1's luminosity. Hence, if HD1 indeed has Population III stars, it will be the first time these objects have been seen.
Pacucci said, "Answering questions about the nature of a source so far away can be challenging."
Sciencealert noted that it is incredibly difficult to detect things from the early Universe. It was said that even the most powerful telescopes struggle to pick up the light of quasars, the brightest objects in the whole cosmos.
According to CNET, HD2 is another incredibly distant galaxy described in the paper, but because it is not quite as far away, it does not garner as much attention.
