Space and Science

Newly discovered giant galaxies dwarf the Milky Way

CNN  — 

Our universe may be filled with unseen giants. Astronomers have discovered two giant radio galaxies, which are some of the largest-known objects in the universe. This revelation suggests that the enormous galaxies may be more common than previously believed.

The study published Monday in the Monthly Notices of the Royal Astronomical Society.

Astronomers found the two galaxies in new radio maps that were created using the MeerKAT radio telescope in South Africa.

Radio galaxies, which can be quite common, are brightest in radio wavelengths of light. Centaurus A is a well-known radio galaxy to astronomers. It’s the fifth brightest galaxy in the sky and is about 12 million light-years from Earth.

Centaurus A features a supermassive black hole at its center, which releases powerful jets that flow perpendicularly to the galaxy’s disk – a common structure for radio galaxies.

This composite image shows the Centaurus A galaxy in visible, microwave (orange) and X-ray (blue) light. Long jets expand out from the galaxy's central black hole on either side.

Giant radio galaxies, however, are more rare and have jets that exceed 22 times the size of our Milky Way galaxy. The Milky Way is a barred spiral galaxy, which is also fairly common, and looks like it sounds: a spiral-shaped galaxy with a central bar-shaped structure made of stars.

Now, astronomers have found two giant radio galaxies in a rather small patch of sky.

“We found these giant radio galaxies in a region of sky which is only about 4 times the area of the full Moon,” said Jacinta Delhaize, lead study author and research fellow at the University of Cape Town, in a statement.