Astronomers have looked across the vast expanse and seen what they believe is the most distant (and oldest) galaxy ever observed.
The GN-z11 galaxy may not have a flashy name, but it appears to be the most distant and oldest galaxy ever detected, scientists have discovered. Astronomers led by Nobunari Kashikawa, a professor in the astronomy department at the University of Tokyo, have embarked on a mission to find the farthest observable galaxy in the universe to learn more about how it formed and when.
“From previous studies, the GN-z11 galaxy appears to be the most distant galaxy detectable in our country, 13.4 billion light-years, or 134 billion kilometers (or 134 followed by 30 zeros),” Kashikawa he 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 red change of the galaxy – how far its light stretched or moved to the red end of the spectrum. In general, the farther away a cosmic object is from us on Earth, the lower its light will be.
In addition, the team analyzed the emission lines of GN-z11 – chemical signatures observable in light from cosmic objects.
By studying these signatures closely, the team was able to figure out how far light must come from the GN-z11 to reach us, giving them the tools to estimate their total distance from Earth.
“We looked at ultraviolet light specifically because this is the area of the electromagnetic spectrum that we expected to find chemical signatures redshifted,” Kashikawa said. “The Hubble Space Telescope has detected the signature several times in the GN-z11 spectrum.”
“However,” he added, “even Hubble can’t solve the ultraviolet emission lines to the degree we needed. So we turned to a more up-to-date ground spectrograph, an instrument for measuring emission lines.” called MOSFIRE, which is mounted on the Keck I telescope in Hawaii. “
Using MOSFIRE, the team was able to observe and study in detail the emission lines 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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