An international team of scientists has pushed the limits of radio astronomy to detect a faint signal emitted by hydrogen gas in a galaxy more than five billion light years away - almost double the previous record.
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Using the Very Large Array of the National Radio Astronomy Observatory in the U.S., the team observed radio emission from hydrogen in a distant galaxy and found that it would have contained billions of young, massive stars surrounded by clouds of hydrogen gas.
As the most abundant element in the Universe and the raw fuel for creating stars, hydrogen is used by radio astronomers to detect and understand the makeup of other galaxies.
However, until now, radio telescopes have only been able to detect the emission signature of hydrogen from relatively nearby galaxies.
"Due to the upgrade of the Very Large Array, this is the first time we've been able to directly measure atomic hydrogen in a galaxy this far from Earth," lead author, Ximena Fernández from Rutgers, the State University of New Jersey, said.
"These signals would have begun their journey before our planet even existed, and after five billion years of travelling through space without hitting anything, they've fallen into the telescope and allowed us to see this distant galaxy for the very first time."
As an archaeologist digs down they find older and older objects. The same is true for astronomers - as they build bigger telescopes and develop new techniques to see farther into the Universe, they look further and further back in time.
"This is precisely the goal of the project, to study how gas in galaxies has changed through history," Fernández said.
"A question we hope to answer is whether galaxies in the past had more gas being turned into stars than galaxies today. Our record breaking find is a galaxy with an unusually large amount of hydrogen."
This success for the team comes after the first 178 hours of observing time with the Karl G. Jansky Very Large Array (VLA) radio telescope for a new survey of the sky called the 'COSMOS HI Large Extragalactic Survey', or CHILES for short.
Once it's completed the CHILES survey will have collected data from more than 1,000 hours of observing time. ■