Astronomers have looked out into the vast expanse and seen what they believe is the most distant (and oldest) galaxy ever observed.
The galaxy GN-z11 may not have a flashy name, but it appears to be the most distant and oldest galaxy ever discovered, scientists have discovered. Astronomers led by Nobunari Kashikawa, a professor in the department of astronomy at the University of Tokyo, embarked on a mission to find the most distant observable galaxy in the universe, to learn more about how it formed and when.
“Previous studies show that the galaxy GN-z11 is the furthest detectable galaxy from us, at 13.4 billion light years or 134 non-million kilometers (that’s 134 followed by 30 zeros),” Kashikawa said in a statement. “But measuring and verifying such a distance is not an easy task.”
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To determine how far GN-z11 is from us here on planet Earth, Kashikawa’s team studied the galaxy’s redshift – how much its light has extended or shifted to the red end of the spectrum. In general, the further away a cosmic object is from us on Earth, the more redshifted the light will be.
In addition, the team looked at the emission lines of GN-z11 – observable chemical signatures in the light from cosmic objects.
By closely studying these signatures, the team was able to figure out how far the light coming from GN-z11 must have traveled to get to us, giving them the means to estimate the total distance from Earth. .
“We looked specifically at ultraviolet light, because that’s the area of the electromagnetic spectrum that we expected to find the redshifted chemical signatures,” said Kashikawa. “The Hubble Space Telescope has detected the signature multiple times in the spectrum of GN-z11.”
“However,” he added, “even Hubble cannot resolve the ultraviolet emission lines to the extent we need. Mounted on the Keck I telescope in Hawaii.”
Using MOSFIRE, the team was able to observe and study in detail the emission lines emerging from the galaxy. If other observations confirm the new findings, GN-z11 would officially reign as the most distant galaxy ever seen.
The new study was published on December 14 in the journal Nature Astronomy.
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