Scientists have 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.
Using the Very Large Array of the National Radio Astronomy Observatory in the US, 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.
The previous record was set in 2014 when researchers from Swinburne University in Australia used the Arecibo radio telescope in Puerto Rico to detect atomic hydrogen in a galaxy three billion light years from Earth.
“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,” said lead author Ximena Fernandez from Rutgers University in the US.
“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,” said Fernandez.
“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,” said Fernandez.
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.
Once it is completed the CHILES survey will have collected data from more than 1,000 hours of observing time.
The study was published in the Astrophysical Journal Letters.