Magnetic structure of our Galaxy: A review of observations

Abstract

The magnetic structure in the Galactic disk, the Galactic center and the Galactic halo can be delineated more clearly than ever before. In the Galactic disk, the magnetic structure has been revealed by starlight polarization within 2 or 3 kpc of the Solar vicinity, by the distribution of the Zeeman splitting of OH masers in two or three nearby spiral arms, and by pulsar dispersion measures and rotation measures in nearly half of the disk. The polarized thermal dust emission of clouds at infrared, mm and submm wavelengths and the diffuse synchrotron emission are also related to the large-scale magnetic field in the disk. The rotation measures of extragalactic radio sources at low Galactic latitudes can be modeled by electron distributions and large-scale magnetic fields. The statistical properties of the magnetized interstellar medium at various scales have been studied using rotation measure data and polarization data. In the Galactic center, the non-thermal filaments indicate poloidal fields. There is no consensus on the field strength, maybe mG, maybe tens of uG. The polarized dust emission and much enhanced rotation measures of background radio sources are probably related to toroidal fields. In the Galactic halo, the antisymmetric RM sky reveals large-scale toroidal fields with reversed directions above and below the Galactic plane. Magnetic fields from all parts of our Galaxy are connected to form a global field structure. More observations are needed to explore the untouched regions and delineate how fields in different parts are connected.

10+1 pages. Invited Review for IAU Symp.259: Cosmic Magnetic Fields: From Planets, to Stars and Galaxies (Tenerife, Spain. Nov.3-7, 2009). K.G. Strassmeier, A.G. Kosovichev & J.E. Beckman (eds.)

References in corpus (10)

• Three Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis
• Radio observational constraints on Galactic 3D-emission models
• Rotation Measures of Extragalactic Sources Behind the Southern Galactic Plane: New Insights into the Large-Scale Magnetic Field of the Inner Milky Way
• New pulsar rotation measures and the Galactic magnetic field
• The spatial energy spectrum of magnetic fields in our Galaxy
• Observational constraints on models for the interstellar magnetic field in the Galactic disk
• Results of SPARO 2003: Mapping Magnetic Fields in Giant Molecular Clouds
• The Galactic distribution of magnetic fields in molecular clouds and HII regions
• Magnetic field near the central region of the Galaxy: Rotation measure of extragalactic sources
• Extragalactic sources towards the central region of the Galaxy

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• Magnetic fields and cosmic ray anisotropies at TeV energies
• Cosmic ray knee and new physics at the TeV scale
• Connecting the interstellar magnetic field at the heliosphere to the Loop I superbubble
• On the Non-Minimal Coupling of Magnetic Fields with Gravity in Schwarzschild Spacetime