Astronomers in Montréal, Québec, and India captured a radio signal emitted by a galaxy nearly 9 billion years ago. Radio signals from nearby galaxies are easy to pickup, but this is the most distant signal detected so far.
Researchers said the accomplishment opens up new opportunities for exploring the evolution of stars and galaxies with low-frequency radio telescopes.
“It’s the equivalent to a look-back in time of 8.8 billion years,” said Arnab Chakraborty, a post-doctoral cosmology researcher at McGill’s Department of Physics, in a statement.
The signal comes from a distant galaxy called SDSSJ0826+5630. When the signal was emitted, the galaxy was still forming stars and the Universe was only 4.9 billion years old. It was detected with the help of the Giant Metrewave Radio Telescope in India and at a specific wavelength known as the 21 cm line.
A phenomenon called gravitational lensing magnified the signal through the presence of another massive body between the target and the observer. In this case, it was another galaxy.
“This effectively results in the magnification of the signal by a factor of 30, allowing the telescope to pick it up,” said Nirupam Roy, an associate professor in the Department of Physics at the Indian Institute of Science, in a statement.
The researchers were able to use the signal to observe the atomic mass of the galaxy’s gas content. They concluded it is almost twice the mass of the stars visible to us. Chakraborty said other astronomers will now be able to use gravitational lensing to study the composition of galaxies at much greater distances from Earth.
