Space
NASA Hubble Telescope Identifies Youngest Galaxy in the Universe Yet
Catherine Griffin
First Posted: Nov 02, 2013 01:55 PM EDT
Astronomers have officially identified the earliest galaxy ever detected. In a major new survey of the early universe conducted by NASA's Hubble Space Telescope, scientists have discovered the most distant galaxy yet.
The survey itself was actually not designed to find such bright early galaxies. The surprise finding suggests that the infant universe may harbor a much larger number of intense, star-forming galaxies than astronomers believed possible. This means that theories and predictive models of the distribution of galaxies' star formation activity may need revision.
"We expected to find a lot more small objects with this survey," said Mauro Giavalisco, one of the researchers, in a news release. In fact, theory predicts there should be "many small-mass galaxies but just a few large ones. And our survey was not really designed to find these early galaxies with such high rate of star formation. However, on the first try we see this very active object. So we're not sure if we're really, really lucky or if our predictive models are slightly off."
In order to detect this galaxy, the researchers employed a technique called the Lyman-break selection. This method exploits the apparent colors of galaxies as a crude distance indicator. Then, the astronomers gathered a more accurate prediction of the galaxy's distance, they employed sensitive spectroscope telescopes. This allowed them to detect a specific spectral feature emitted by hydrogen known as the Lyman-alpha emission line.
Lyman alpha light is a powerful probe of the early universe. It cannot penetrate the natural hydrogen gas that envelops young galaxies, but it can propagate freely through ionized gas bubbles around older, more evolved galaxies. Therefore, detecting Lyman-alpha from a very early galaxy suggests that its neutral hydrogen volume is small.
In the end, the astronomers examined a time when the universe was only 700 million years old, compared to the 13.8 billion years of today. It was 8.5 times smaller than today and also 600 times more dense and expanding 8.5 times faster.
The findings are important for understanding galaxy formation in the early universe. More specifically, the new galaxy reveals that it's possible that current theories concerning galaxy creation may need to be revised.
The findings are published in the journal Nature.
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First Posted: Nov 02, 2013 01:55 PM EDT
Astronomers have officially identified the earliest galaxy ever detected. In a major new survey of the early universe conducted by NASA's Hubble Space Telescope, scientists have discovered the most distant galaxy yet.
The survey itself was actually not designed to find such bright early galaxies. The surprise finding suggests that the infant universe may harbor a much larger number of intense, star-forming galaxies than astronomers believed possible. This means that theories and predictive models of the distribution of galaxies' star formation activity may need revision.
"We expected to find a lot more small objects with this survey," said Mauro Giavalisco, one of the researchers, in a news release. In fact, theory predicts there should be "many small-mass galaxies but just a few large ones. And our survey was not really designed to find these early galaxies with such high rate of star formation. However, on the first try we see this very active object. So we're not sure if we're really, really lucky or if our predictive models are slightly off."
In order to detect this galaxy, the researchers employed a technique called the Lyman-break selection. This method exploits the apparent colors of galaxies as a crude distance indicator. Then, the astronomers gathered a more accurate prediction of the galaxy's distance, they employed sensitive spectroscope telescopes. This allowed them to detect a specific spectral feature emitted by hydrogen known as the Lyman-alpha emission line.
Lyman alpha light is a powerful probe of the early universe. It cannot penetrate the natural hydrogen gas that envelops young galaxies, but it can propagate freely through ionized gas bubbles around older, more evolved galaxies. Therefore, detecting Lyman-alpha from a very early galaxy suggests that its neutral hydrogen volume is small.
In the end, the astronomers examined a time when the universe was only 700 million years old, compared to the 13.8 billion years of today. It was 8.5 times smaller than today and also 600 times more dense and expanding 8.5 times faster.
The findings are important for understanding galaxy formation in the early universe. More specifically, the new galaxy reveals that it's possible that current theories concerning galaxy creation may need to be revised.
The findings are published in the journal Nature.
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone