The Role of Magnetic Fields in the Interstellar Medium

It has been known for many years that magnetic fields exist in the interstellar medium (ISM), although their role in shaping and driving the evolution of the ISM remains debated. Some theories cast magnetic fields as the key agents of evolution, whilst other theories dismiss them altogether as only a minor perturbation on an otherwise turbulent picture. Since our sister Research Topic, ‘The role of magnetic fields in star formation’ (Ward-Thompson et al., 2020), was published by Frontiers six years ago, the field has moved on somewhat. Interferometers such as ALMA, NOEMA and SMA have received new instruments with improved polarimetric capability, enhancing our sensitivity to objects in our Galaxy as well as in other nearby galaxies. In addition, single-dish telescopes such as JCMT, Nobeyama and IRAM have now carried out large-scale surveys, placing the role of magnetic fields onto a more statistical footing. It is therefore timely to revisit the question of the role of magnetic fields in the ISM.This Research Topic aims to synthesize our current understanding of the role of magnetic fields in the interstellar medium and in star formation. It will trace the magnetic field from the diffuse interstellar medium, through the formation of molecular clouds and filaments, to dense cores and proto-stellar collapse — including the Central Molecular Zone of the Milky Way — and offer a comparative perspective on the magnetic fields of other nearby disk galaxies. Contributions will cover the principal observational techniques — dust polarimetry, Zeeman measurements, and Faraday rotation — together with the physics of grain alignment, and will confront these measurements with theory and numerical simulations of magnetized turbulence and cloud evolution. Our goals are to assess critically how magnetic fields regulate the formation of molecular clouds and stars, to identify the key open questions, and to provide a roadmap for the coming decade of observations with new facilities.In defining the scope of this Research Topic, the editors considered whether to extend the collection to the circulation of matter and energy in the Galaxy — gas accretion through high-velocity clouds and, ultimately, its exchange with the circum-galactic medium. We decided to leave these topics outside the present collection, and we look forward to the rapid progress expected in this field in the near future. Topic editors: Derek Ward-Thompson, Christopher F. McKee, Ray S. Furuya, Ralph E. Pudritz Source: https://www.frontiersin.org/research-topics/81821/the-role-of-magnetic-fields-in-the-interstellar-medium