Recently, a group of astronomers discovered a distant galaxy. She is the faintest radio-emitting object ever discovered.
The discovery of the faintest radio galaxy is part of an exploration of the VLA Frontier Fields legacy by NRAO astronomer Eric Murphy. It was made possible by radio telescopes and gravitational lenses.
Distant galaxy clusters have been used by astronomers as natural lenses to carefully study the most distant objects. The clusters acted as gravitational lenses to bend and magnify light and radio waves. In this way, they helped the world’s most sensitive radio receivers – radio telescopes. They are capable of detecting very weak beams of radiation from objects in the most distant corners of the universe.
In the composite photograph above, the VLA radio image is superimposed on the visible light image taken by the Hubble Space Telescope. The prominent red-orange objects are radio relics (large structures, possibly caused by shock waves) – within the foreground galaxy cluster. The galaxy cluster MACSJ0717.5 + 3745 is located more than 5 billion light years from Earth.
Detailed VLA observations have shown that many of the galaxies in this image emit radio waves in addition to visible light. One of them is located more than 8 billion light years away. Its light and radio waves are distorted by the gravitational lensing effect of the intermediate cluster.
According to astronomers, the radio image of this distant galaxy, dubbed VLAHFF-J071736.66 + 374506.4, has been magnified by a gravitational lens by more than 6 times. This is what allowed the VLA to find him.
“This is probably the faintest radio-emitting object ever discovered,” said Ian Haywood of Oxford University in the UK. “This is why we want to use these galaxy clusters as powerful cosmic lenses to learn more about the objects behind them.”