Today's Colloquium: Magnetic fields in the multi-phase interstellar medium

© Left: Fletcher & Beck/Hubble Heritage Team/Sterne & Weltraum, Right: Evirgen et al. 2017, MNRAS, 464, L105

Left: yellow lines show the observed radio polarisation angles of the galaxy M51, tracing out spiral magnetic-field lines that are ordered on the scale of the galaxy. Right: black lines show the mean magnetic field lines in a simulation of the interstellar medium, with the gas entropy shown in colour; the hot gas is yellow, the warm gas is red and the magnetic field prefers the latter. Today's colloquium will discuss and connect the observations and simulations.