Astronomers have looked into the vast expanses and seen what they think is the longest (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 discovered, scientists have found. Astronomers led by Nobunari Kashikawa, a professor in the Department of Astronomy at the University of Tokyo, embarked on a mission to find the universe’s most distant observable galaxy to learn more about how it formed and when.
“From previous studies, it appears that the galaxy GN-z11 is the most distant detectable galaxy from us at 13.4 billion light-years or 134 non-million kilometers (that is 134 followed by 30 zeros),” Kashikawa said in a statement. “But measuring and controlling 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 examined the redshift of galaxies – how much its light has extended or shifted toward the red end of the spectrum. In general, the farther away a cosmic object is from us on earth, the more redshift its light will be.
In addition, the team looked at the GN-z11’s emission lines – observable, chemical signatures in the light coming from cosmic objects.
By studying these signatures closely, the team was able to determine how far the light from GN-z11 must have traveled to reach us, giving them the tools to estimate the total distance from Earth.
“We looked specifically at ultraviolet light, as that is the area of the electromagnetic spectrum we expected to find the red-shifted chemical signatures,” Kashikawa said. “The Hubble Telescope detected the signature several times in the range of the GN-z11.”
“However,” he added, “even Hubble cannot solve ultraviolet emission lines to the extent we needed. So we turned to a more up-to-date terrestrial spectrograph, an instrument for measuring emissions, called MOSFIRE, which is mounted on Keck. The Hawaiian Telescope. “
Using MOSFIRE, the team was able to observe and study the emission lines coming from the galaxy in detail. If other observations confirm the new findings, GN-z11 would officially rule as the most distant galaxy ever seen.
The new study was published on December 14th in the journal Nature Astronomy.
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