As galaxies plunge into galaxy clusters, they force their way through gas and dust and often gravitationally interact with other systems. All these interactions leave galaxies looking a bit ratty, and one class of irregular systems have been dubbed jellyfish galaxies because their leading edge is compressed, and they end up trailing star-forming regions behind them in what look like arms.  

In new research appearing in Nature Astronomy and led by Ancla Muller, astronomers take a deep look at the jellyfish galaxy JO 206 to determine if magnetic fields play a role in knitting together these structures. The answer is yes! They were able to determine that the galaxy’s strong magnetic field is aligned with the arms. According to co-author Christoph Pfrommer: While the jellyfish galaxy flies through the galaxy cluster, its magnetic field wraps around the galaxy like a mantle and is further amplified and smoothed by the high galaxy speed and cooling effects.

According to the press release: JO206 falls at high speed into the center of the galaxy cluster, so that the magnetic fields interact and hot winds from the medium between the galaxies lead to accumulations of plasma. A percentage of the plasma condenses on the outer layers of the gas tail, where it mixes with the remaining matter. This would provide enough material for star formation. It should be fascinating to see whether this picture can be confirmed by further measurements on other objects.

I can’t wait to see their future jellyfish in space measurements. This is the kind of science and amusement needed in 2020.

More Information

Ruhr-Universität Bochum press release 

“Highly Ordered Magnetic Fields in the Tail of the Jellyfish Galaxy JO206,” Ancla Müller et al., 2020 Oct. 26, Nature Astronomy (preprint on arxiv.org)