Radio Signal from 9 Billion Light-years Away from Earth Captured

Researchers say they have detected a radio signal from the most distant galaxy located about 9 billion light years away.

The signal, which has a characteristic wavelength called the 21 cm line, is helping to answer questions about the early universe, according to a McGill University.

The radio signal captured by the Giant Metrowave Radio Telescope in India was detected in a galaxy known as SDSSJ0826+5630.

Researchers from McGill University and the Indian Institute of Science, studied the signal and found that it was emitted when the universe was 4.9 billion years old. 

"This is the equivalent of looking back 8.8 billion years in time" said McGill post-doctoral researcher Arnab Chakraborty.

The researchers said the telescope was able to capture the distant signal because it was bent by another galaxy located between the signal and the telescope. 

"As a result, the signal is effectively amplified up to 30 times, enabling the telescope to capture it" said Nirupam Roy, co-author of the study and associate professor at IIS India.

This signal bending is called gravitational lensing, and it can help researchers observe the cosmic evolution of distant galaxies and stars.

"A galaxy emits a variety of radio signals. Until now, it has only been possible to pick up on this particular signal from a nearby galaxy, limiting our knowledge to galaxies close to Earth," Chakraborty said. 

"But with the help of a naturally occurring phenomenon called gravitational lensing, we can capture a weak signal from a record-breaking distance. This will help us understand the structure of galaxies at much greater distances from Earth."

The researchers were able to determine that the atomic mass of the hydrogen gas in SDSSJ0826+5630 is about twice the mass of the stars we see. 

The hydrogen gas "provides the basic fuel for star formation in the Milky Way," the researchers wrote in the study. 

"Understanding the evolution of galaxies over cosmic time requires knowledge of the cosmological evolution of this neutral gas."

The research suggests that scientists may be able to probe the cosmic evolution of neutral gas with low-frequency radio telescopes in the near future.