Known as Y1, the galaxy is so distant its light has traveled for over 13 billion years to reach Earth. The team detected the presence of intensely heated cosmic dust and measured the dust temperature at 90 Kelvin, much warmer than that seen in any other comparable galaxy by this point in cosmic history.
"We're looking back to a time when the universe was making stars much faster than today. Previous observations revealed the presence of dust in this galaxy, making it the furthest away we've ever directly detected light from glowing dust. That made us suspect that this galaxy might be running a different, superheated kind of star factory. To be sure, we set out to measure its temperature," said Tom Bakx.
Powerful observations with ALMA, operated in Chile, allowed the team to capture the galaxy's emission at a wavelength of 0.44 millimetres. The measured brightness showed the dust shining far hotter than typical, indicating extreme and rapid star formation.
"At wavelengths like this, the galaxy is lit up by billowing clouds of glowing dust grains. When we saw how bright this galaxy shines compared to other wavelengths, we immediately knew we were looking at something truly special," said Bakx.
Yoichi Tamura, astronomer at Nagoya University, Japan, explained that Y1's star production rate exceeds 180 solar masses per year, compared to about one per year in the Milky Way. This extreme activity cannot be sustained for long periods, and such intense bursts of star formation may have been more common in the early universe.
"We don't know how common such phases might be in the early universe, so in the future we want to look for more examples of star factories like this. We also plan to use the high-resolution capabilities of ALMA to take a closer look at how this galaxy works," Bakx said.
The findings may help address why some early galaxies appear to contain more dust than stellar processes should permit. Laura Sommovigo from the Flatiron Institute and Columbia University in the USA noted, "Galaxies in the early universe seem be too young for the amount of dust they contain. That's strange, because they don't have enough old stars, around which most dust grains are created. But a small amount of warm dust can be just as bright as large amounts of cool dust, and that's exactly what we're seeing in Y1. Even though these galaxies are still young and don't yet contain much heavy elements or dust, what they do have is both hot and bright."
Research Report:A warm ultraluminous infrared galaxy just 600 million years after the Big Bang
Related Links
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