SPACE — Astronomers have accidentally discovered a dark galaxy composed of pristine primordial gas. This galaxy appears to have no visible stars.
Primordial gas is a gas composed mainly of hydrogen and helium that formed shortly after the Big Bang. This gas had not become enriched when the star exploded and sprinkled it with heavy elements or “metals”.
Discoveries of primordial gases usually occur during the early formation of the universe or perhaps billions of light-years from Earth.
The researchers say the galaxy, called J0613+52, may be “the faintest galaxy discovered to date.” Interestingly, scientists discovered this dark galaxy by chance using the Green Bank Telescope (GBT).
“GBT was accidentally pointed at the wrong coordinates and discovered this object. This is a galaxy made only of gas with no visible stars,” said Karen O’Neil, senior scientist at the Green Bank Observatory, in a statement, reported by Space.
“The stars could be there. We just can’t see them.”
This galaxy is full of primordial gas, but its location is very close to Earth. The dark galaxy J0613+52 is only about 270 million light-years from Earth.
Low luminosity galaxies
J0613+52 was discovered by astronomers while observing hydrogen gas in several low surface brightness (LSB) galaxies. Scientists use several large radio telescopes around the world, including the GBT located in Green Bank, West Virginia, and the Nançay radio telescope at the Paris Observatory.
LSBs tend to have small stellar populations scattered throughout the galaxy. These galaxies generally emit much less light per unit area than galaxies such as the Milky Way or Andromeda. LSBs are usually very difficult to find.
For example, the first LSB discovered was Malin 1, discovered in the 1980s, which is still one of the largest spiral galaxies ever seen, with a width five times that of the Milky Way. Despite being so large, Malin 1 is only 1% as bright as our galaxy.
The LSB also appears to grow much more slowly than other galaxies. Many LSBs are still experiencing the early stages of star formation. Astronomers believe this is due to the low density of their gas, meaning clumps of gas that are too dense cannot come together to form stars.
Unique dark galaxy
J0613+52 is an LSB like the other 350 galaxies discovered in the survey. However, this galaxy is unique.
This galaxy is very rich in gas. “This doesn’t show star formation as we expected, perhaps because the gas is too spread out,” O’Neil said.
“At the same time, this galaxy is too far from other galaxies to help trigger star formation through any encounters.”
2024-01-13 07:10:00
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