As with many things in life, the universe is filled with things you can only see if you look just the right way. Today we’re learning that when it comes to finding massive galaxies with massive jets, the MeerKAT radio observatory in South Africa has the sensitivity to see things like never before.

We have known for many decades that there are galaxies with glorious jets of particles streaming away from their cores that produce radio light. So far very few have been found, especially those with extremely long jets, but MeerKAT was able to find two giant radio galaxies with jets more than twenty times the size of the Milky Way.  Surprisingly, these systems were both found in a remarkably small patch of the sky during a new survey.

According to study lead author Jacinta Delhaize: We found these giant radio galaxies in a region of sky which is only about 4 times the area of the full Moon. Based on our current knowledge of the density of giant radio galaxies in the sky, the probability of finding two of them in this region is less than 0.0003 percent. This means that giant radio galaxies are probably far more common than we thought!

A release related to this paper, which appears in the Monthly Notices of the Royal Astronomical Society, goes on to explain: It is thought that the giants are the oldest radio galaxies, which have existed for long enough (several hundred million years) for their radio jets to grow outwards to these enormous sizes. If this is true, then many more giant radio galaxies should exist than are currently known.

These two systems were discovered thanks to the remarkable sensitivity of MeerKAT, and this new telescope is only a precursor of things to come. Not only will MeerKAT be observing more of the sky, but the construction of an even larger and more sensitive system, called the Square Kilometre Array, will begin later this year.

More Information

Royal Astronomical Society press release

“MIGHTEE: are giant radio galaxies more common than we thought?“, J. Delhaise et al., 2020 December 14, Monthly Notices of the Royal Astronomical Society