Astronomers have looked into the distance and discovered 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 found. Astronomers, led by Nobunari Kashikawa, professor at the Institute of Astronomy at Tokyo University, embarked on a mission to find the most distant observable galaxy in the universe and learn more about how and when it was formed.
“Previous studies show that the galaxy GN-z11, at 13.4 billion light years or 134 million kilometers (that’s 134 followed by 30 zeros), is the furthest detectable galaxy from us,” said Kashikawa said in a statement. “However, measuring and verifying such a distance is not an easy task.”
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To determine how far away GN-z11 is from us here on planet Earth, Kashikawa’s team studied the galaxy’s redshift – how much its light has expanded or shifted to the red end of the spectrum. In general, its light is redshifted the further away a cosmic object is from us on earth.
In addition, the team examined the emission lines of GN-z11 – observable chemical signatures in the light of cosmic objects.
By carefully studying these signatures, the team was able to figure out how far the light coming from GN-z11 must have come to get to us and give them the tools to estimate the total distance from Earth.
“We looked specifically at ultraviolet light because this is the part of the electromagnetic spectrum that we expected to find the red-shifted chemical signatures,” said Kashikawa. “The Hubble Space Telescope recognized the signature in the spectrum of GN-z11 several times.”
“However,” he added, “even the Hubble cannot resolve ultraviolet emission lines to the extent we need, so we turned to a more recent ground-based spectrograph, an emission line measurement instrument called MOSFIRE mounted on the Keck I telescope in Hawaii . “
With MOSFIRE, the team was able to observe and examine the galaxy’s emission lines in detail. If other observations confirm the new findings, GN-z11 would officially be considered the most distant galaxy ever seen.
The new study was released on December 14th in the journal Nature Astronomy.
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