Related papers: Radio Observations of the Magnetic Fields in Galax…
Radio continuum observations allow to reveal the magnetic field structure in the disk and halo of nearby spiral galaxies, their magnetic field strength and vertical scale heights. The spiral galaxies studied so far show a similar magnetic…
Total magnetic fields in spiral galaxies, as observed through their total synchrotron emission, are strongest (up to \simeq 30\mu G) in the spiral arms. The degree of radio polarization is low; the field in the arms must be mostly turbulent…
Observational evidence for dynamo action in spiral galaxies is reviewed, and the capabilities of various theories in explaining the basic features of galactic magnetic fields are discussed. Mean-field dynamo models appear to be unique in…
Radio synchrotron emission is a powerful tool to study the strength and structure of magnetic fields in galaxies. Unpolarized synchrotron emission traces isotropic turbulent fields which are strongest in spiral arms and bars (20-30 \mu G)…
Magnetic fields in our Galaxy and nearby galaxies have been revealed by starlight polarization, polarized emission from dust grains and clouds at millimeter and submillimeter wavelength, the Zeeman effect of spectral lines or maser lines…
The strength of the total magnetic field in our Milky Way from radio Zeeman and synchrotron measurements is about 6 muG near the Sun and several mG in dense clouds, pulsar wind nebulae, and filaments near the Galactic Center. Diffuse…
Observations of synchrotron radiation and the Faraday rotation of its polarized component allow us to investigate the magnetic properties of the diffuse interstellar medium in nearby galaxies, on scales down to roughly one hundred parsecs.…
Spiral galaxies host dynamically important magnetic fields which can affect gas flows in the disks and halos. Total magnetic fields in spiral galaxies are strongest (up to 30 \muG) in the spiral arms where they are mostly turbulent or…
Both observations and modelling of magnetic fields in the diffuse interstellar gas of spiral galaxies are well developed but the theory has been confronted with observations for only a handful of individual galaxies. There is now sufficient…
In this review, I will first introduce possible methods to probe the large-scale magnetic fields in our Galaxy and discuss their limitations. The magnetic fields in the Galactic halo, mainly revealed by the sky distribution of rotation…
Most of the visible matter in the Universe is ionized, so that cosmic magnetic fields are quite easy to generate and due to the lack of magnetic monopoles hard to destroy. Magnetic fields have been measured in or around practically all…
Many galaxies contain magnetic fields supported by galactic dynamo action. However, nothing definitive is known about magnetic fields in ring galaxies. Here we investigate large-scale magnetic fields in a previously unexplored context,…
Context. Observations of polarized radio emission show that large-scale (regular) magnetic fields in spiral galaxies are not axisymmetric, but generally stronger in interarm regions. In some nearby galaxies such as NGC 6946 they are…
The existence of magnetic fields associated with the intracluster medium in clusters of galaxies is now well established through different methods of analysis. The most detailed evidence for the presence of cluster magnetic fields comes…
Magnetic fields have been observed on all scales in our Galaxy, from AU to kpc. With pulsar dispersion measures and rotation measures, we can directly measure the magnetic fields in a very large region of the Galactic disk. The results show…
The average strength of the total magnetic field in the Milky Way, derived from radio synchrotron data under the energy equipartition assumption, is 6\muG locally and \simeq 10\muG at 3 kpc Galactic radius. Optical and synchrotron…
Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale structures. A large-scale field reversal may exist in the Milky Way but no such reversals have been observed so far in external galaxies. The…
Constraining dynamo theories of magnetic field origin by observation is indispensable but challenging, in part because the basic quantities measured by observers and predicted by modelers are different. We clarify these differences and…
Radio continuum and polarization observations of several nearby galaxies allowed to determine their vertical scaleheights, magnetic field strengths and large-scale magnetic field patterns. They all show a similar large-scale magnetic field…
The main observational results from radio continuum and polarization observations about the magnetic field strength and large-scale pattern for face-on and edge-on spiral galaxies are summarized and compared within our sample of galaxies of…