What happens when two galaxies collide?

One of the brightest galaxies in the night sky, Centaurus A, is well known for its distinct “S” shape. This shape is believed to be the result of a clash between a spiral and an elliptical galaxy about 100 million years ago.

Now, for the first time, scientists have mapped out the invisible magnetic fields pulsing through Centaurus A using infrared light. The results show how the merging of the two original galaxies created a new, reshaped, and contorted galaxy that not only combined the two galaxies’ magnetic fields but amplified their forces.

The new observations, made with NASA’s airborne Stratospheric Observatory for Infrared Astronomy, SOFIA, provide new insights into how the early universe may have been shaped by galactic mergers under the influence of their supercharged magnetic fields. The results were recently published in Nature Astronomy.

“Magnetic fields were key to shaping the early universe, but they did not start out as the forces we know today; somehow they grew stronger over time,” said Dr. Enrique Lopez-Rodriguez a research scientist at Stanford Kavli Institute for Particle Astrophysics and Cosmology in Stanford, California. “Galactic mergers appear to be one of the strengthening mechanisms.”

Since it is relatively close by intergalactic standards, at 13 million light-years away, Centaurus A makes a good candidate to study galactic mergers. The new view of the large-scale magnetic fields, which span  1,600 light-years, found they run parallel to the dust lanes that are remnants of the original spiral galaxy.

Credit: NASA