© Henrik Edler

Galaxy clusters consist of hundreds to thousands of galaxies, embedded in the hot intracluster medium (ICM). Compared to isolated systems, cluster galaxies form fewer stars. This is due to environmental processes such as ram pressure stripping, which can remove cold gas from galaxies. Clusters grow through mergers with other structures, and mergers between clusters represent the most energetic events in the present-day Universe, launching large-scale shock waves into the ICM.

In our new study (https://arxiv.org/abs/2512.15660 , we investigated how such shock waves affect cluster galaxies, using the nearby merging cluster Abell 1367 as a case study. We observed the system with LOFAR (LBA and HBA) and MeerKAT, focusing on three galaxies currently undergoing strong ram-pressure stripping. Our sensitive radio observations reveal stripped tails extending up to 300 kpc - the longest such structures known at any wavelength.

Neither the extreme length nor the radio spectra of the tails are in agreement with a simple "aging" of the stripped radio plasma due to radiative energy losses. Instead, we show that their properties are consistent with a model that includes magnetic field compression and particle acceleration caused by the merger shock. This interaction with the shock can naturally explain the orientation, spectral properties, and exceptional length of the tails, as well as the unusually strong ram-pressure stripping. In Abell 1367, we can witness how the large-scale cluster dynamics affect the evolution of individual member galaxies.