New image smashes 19-year record for most distant radio galaxy photographed

9 Aug 2018

A colliding galaxy system called Arp 220 captured by the Hubble Space Telescope. Image: ALMA (ESO/NAOJ/NRAO)/NASA/ESA and the Hubble Heritage Team (STScI/AURA)

A new image has helped reveal a sight from when the universe was just 1bn years old, smashing a near 20-year record.

The technology we use to look further and further out into the cosmos has developed substantially in the past few years, and now it has revealed a photo of the most distant radio galaxy ever discovered.

In a paper published to the Monthly Notices of the Royal Astronomical Society, an international team of astronomers revealed the location of a galaxy 12bn light years away from Earth.

This means we are observing a time when the universe was just 7pc of its current age, or approximately 1bn years old.

To determine this, the researchers measured the galaxy’s redshift, a phenomenon whereby a galaxy located in distant space travelling at great speeds from Earth will appear redder than slower ones.

To even find a radio galaxy at all is something of a major achievement as they are quite rare objects in the universe, even though they are gigantic in size with a supermassive black hole in the centre.

Radio galaxy image

This picture shows the near-infrared image taken using the Large Binocular Telescope in Arizona, with radio emission overlaid in white. Image: Leiden Observatory

A very rare sight

As one of these black holes actively accumulates gas and dust from its surroundings, it initiates the launch of high-energy jet streams, capable of accelerating charged particles around the supermassive black hole to almost the speed of light.

These jets help astronomers on Earth spot them more easily as they are clearly observed at radio wavelengths.

However, the fact that we are able to see such galaxies at a time when the universe was just an infant has somewhat puzzled astronomers.

“It is very surprising how these galaxies have built up their mass in such a short period of time,” said co-author of the study Huub Röttgering of Leiden Observatory in the Netherlands.

“Bright radio galaxies harbour supermassive black holes. It is amazing to find such objects as early in the history of the universe; the time for these supermassive black holes to form and grow must have been very short.”

The last time a galaxy with a similar redshift was spotted was all the way back in 1999. With the next generation of radio telescopes coming down the line, astronomers will be able to detect radio galaxies at even greater redshifts in future.

Colm Gorey was a senior journalist with Silicon Republic