Recipe for regularity

摘要

Galaxies, particularly those that, like our own Milky Way, actively form stars, are complex systems in which a vast array of physical processes operate simultaneously (Fig. 1). Patterns of regularity in galaxy behaviour are often interpreted, therefore, as evidence for global self-organization, and thus for the workings of the system at a fundamental level. One such pattern is a remarkably tight correlation between the rate of star formation and that of synchrotron radiation from cosmic-ray electrons gyrating in the galactic magnetic field. This correlation has now been reinterpreted by Schleicher and Beck, through the lens of modern ideas about magnetic-field amplification in galaxies, in a paper published in Astronomy & Astrophysics. The authors provide predictions about the evolution of the correlation, and the physical quantities underlying it, over cosmic time.