Astronomers Measure The Distance To The Farthest Galaxy In The Universe
The team of astronomers used the Keck I telescope to measure the distance to an ancient galaxy described as the farthest galaxy in the universe. The galaxy in question is called GN-z11, and it's both the oldest and most distant galaxy from us. The astronomers say that the galaxy is so far away that it defines the observable universe's boundary.
Astronomers used chemical signatures to measure the distance to GN-z11. They hope that the study can shed light on a period of cosmological history from the universe that was only a few hundred million years old. The key question that scientists want to answer is how and when did galaxies form. Professor Nobunari Kashikawa from the Department of Astronomy at the University of Tokyo says that he wanted to find out how and when the most distant galaxy we can observe came to be.
He said that previous studies have found that GN-z11 appears to be the most distant detectable galaxy from the Earth at 3.4 billion light-years away. Measuring and verifying such a massive distance wasn't easy. The team used redshift to measure the distance, which refers to the way light stretches out and becomes redder.
The team also measured chemical signatures known as emission lines that imprint patterns in the light from distant objects. By measuring how to stretched the signals are, astronomers were able to deduce how far the light must've traveled, revealing the distance from the target galaxy.
The team specifically looked at the electromagnetic spectrum to find the redshifted chemical signatures.
Those signals had been detected multiple times in the spectrum of the distant galaxy by the Public Space Telescope. As powerful as Hubble is, it was unable to resolve the ultraviolet emission lines to the degree the researchers needed. To get the project's resolution, they turned to the MOSFIRE instrument mounted on the Keck I telescope in Hawaii. The readings helped the team to improve the accuracy of the galaxy's z value by a factor of 100. Currently, the astronomers are waiting for subsequent observations to confirm their findings.