WLM is a gas-rich dwarf galaxy in our Local Group, so isolated and distant that it has never interacted with other galaxies. However, this image from the MeerKAT radio telescope reveals that WLM is interacting with a very low-density ionised medium located between galaxies, known as the intergalactic medium (IGM). As WLM moves through the IGM, the surrounding medium exerts pressure on its gas, which is then pushed out in the direction opposite to its motion, as seen in the image. This interaction also disturbs the overall dynamics of WLM’s outer regions.
Studying this phenomenon will help constrain the dark matter content of WLM and determine the density of the IGM, a component of the Universe that is notoriously difficult to observe directly.
Credits : Kolhe, Hammer, Yang et al., 2026, Astronomy & Astrophysics in press
