Letters of Intent received in 2016

LoI 2018-1944
New Insights in Galactic and Extragalactic Magnetic Fields

Topics

• Origins of cosmic magnetism
• Capabilities of next generation telescopes for cosmic magnetism
• Magnetism across the electromagnetic spectrum
• Magnetism of the early Universe
• Observations of magnetic fields in molecular clouds and star formation
• Observations of magnetic fields in the Milky Way and nearby galaxies
• Observations and simulations of magnetic fields in radio galaxies and the intergalatic medium
• Observations and simulations of magnetic fields in galaxy clusters and the cosmic web
• Looking ahead: Magnetism in the SKA era

Rationale

Magnetic fields dominate the universal energy balance on a wide variety of spatial scales: regulating star formation in giant molecular clouds, affecting the enrichment of the intergalactic medium by galactic winds and governing the growth of individual galaxies, galaxy clusters, and large-scale structures. Despite their importance and ubiquity, magnetic fields remain poorly understood components of the Universe due to the challenges involved in their measurement. Numerous open questions remain unanswered:
• how did magnetic fields form?
• how did they evolve and how are they maintained?
• how do they control the acceleration and dynamics of relativistic particles in astrophysical plasmas?
• what are the magnetic field strength and structure?
• what is the influence of magnetic fields on other physical parameters ?

Understanding the magnetized Universe is a major challenge in modern astrophysics. Much of what is known about Cosmic Magnetism comes from sensitive radio observations in both total intensity and polarization. This is because the radio emission of astrophysical sources is of synchrotron origin, thus it is a direct probe of relativistic electrons gyrating around magnetic field lines. Moreover, the observed polarization angle is modified from its intrinsic value by the effect of Faraday rotation, when a magneto-ionic medium is present between the source of polarized emission and the telescope. The analysis of the Faraday rotation is a powerful tool to prove the strength and structure of magnetic fields in the Galaxy, in clusters and in the intergalactic medium.

Recent advances in instrumentation, both in the more traditional radio frequency portion of the spectrum, and in the sub-mm, are dramatically advancing our knowledge of the incidence, strength and topology of magnetic fields in astrophysics. In 2018, many data from LOFAR, MWA, ASKAP and MeerKAT should be available to help significantly advance our understanding of galactic and extragalactic magnetic fields. At shorter wavelength, ALMA will provide polarization measurements of magnetic fields in molecular clouds and galaxies. Magnetism is also explored at a broad range of other wavebands using instruments such as Planck, Fermi, LBT, and eROSITA. There will be a wealth of new data which we will have to discuss and understand. At the same time, advances in theory, particularly via high resolution numerical simulations are providing a greatly improved context for interpretation of the observations and to address the origin and amplification of magnetic fields.

It is therefore particularly important to discuss the most recent insights emerging from studies addressing magnetism on a wide range of physical scales via a variety of analysis techniques to allow a comprehensive discussion of the challenges and opportunities which lie ahead with the next generation of data-intensive instruments. 2018 is an excellent time for a summary and planning for the next steps, especially in view of the SKA. Given the huge shift in processing regimes required by new instruments, it is imperative to bring the observational, theoretical and computational communities together in order to discuss the results in hand and develop analysis techniques and observing experiments that must work efficiently. In this way, we accelerate our ability both to explore the massive volumes of data we will accumulate and achieve our ultimate quest to obtain a deeper understanding of the magnetized Universe.

Note: The SOC will be defined considering that the bulk of the meeting is focused on the radio domain, but with involvement of a broader community