Cosmic Rays are now considered an important ingredient for modelling galaxy evolution. Low-frequency radio continuum observations are an excellent way to observe them via synchrotron emission of Cosmic-Ray electrons. We present a study of 45 nearby galaxies using radio continuum observations with the LOw Frequency ARray observed as part of the LOFAR Two-metre Sky Survey (LoTSS). We measure the relation between radio continuum luminosity and star-formation rate and explain our findings with escaping Cosmic Rays in galactic winds. We calculate magnetic field maps with the equipartition assumption and compare them with maps of surface gas densities for both molecular and atomic gas in order to study the magnetic field–gas relation. Combining observations with LOFAR and those at higher frequencies from the Very Large Array, we observe radio haloes in order to study the transport of Cosmic Rays in galactic winds and the role that they play in them. Finally, we present a first tentative signal from magnetic fields in the circumgalactic medium using Faraday rotation of polarised background sources with high precision measurements of the Faraday rotation measure. Our results suggest that the circumgalactic medium around nearby galaxies is magnetised by galactic winds and outflows.
