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Context. Magnetic fields in nearby, star-forming galaxies reveal large-scale patterns, as predicted by dynamo models, but also a variety of small-scale structures. In particular, a large-scale field reversal may exist in the Milky Way while no such reversals have been observed so far in external galaxies. Aims. The effects of star-forming regions in(More)
We present λ3.5 cm and λ6.2 cm radio continuum maps in total and polarized intensity of the barred galaxies NGC 1097 (at 2 ′′ –15 ′′ resolution) and NGC 1365 (at 9 ′′ –25 ′′ resolution). A previously unknown radio galaxy southwest of NGC 1097 is reported. Apart from a smooth faint envelope and a bright central region, both galaxies exhibit radio ridges(More)
We present three-frequency VLA observations of the flocculent spiral galaxy NGC 4414 made in order to study the magnetic field structure in absence of strong density wave flows. NGC 4414 shows a regular spiral pattern of observed polarization B-vectors with a radial component comparable in strength to the azimuthal one. The average pitch angle of the(More)
We present an extensive study of magnetic fields in a system of merging galaxies. We obtained for NGC 4038/39 (the Antennae) radio total intensity and polarization maps at 8.44 GHz, 4.86 GHz and 1.49 GHz using the VLA in the C and D configurations. The galaxy pair possesses bright, extended radio emission filling the body of the whole system, with no(More)
Context. The LOFAR (LOw Frequency ARray) radio telescope is a giant digital phased array interferometer with multiple antennas distributed in Europe. It provides discrete sets of Fourier components of the sky brightness. Recovering the original brightness distribution with aperture synthesis forms an inverse problem that can be solved by various(More)
Low frequency radio waves, while challenging to observe, are a rich source of information about pulsars. The LOw Frequency ARray (LOFAR) is a new radio interferometer operating in the lowest 4 octaves of the ionospheric " radio window " : 10–240 MHz, that will greatly facilitate observing pulsars at low radio frequencies. Through the huge collecting area,(More)
We observed 21 polarized background radio sources in the field of M31 at 1.365 GHz and 1.652 GHz, and determined their rotation measures (RMs). The RM data show that the regular magnetic field of the disk probably extends from about 5 kpc to 25 kpc from the center with similar structure. The RMs obtained from the polarized emission from M31 at λ6 cm and λ11(More)
The role of magnetic fields in the dynamical evolution of galaxies and of the interstellar medium (ISM) is not well understood, mainly because such fields are difficult to directly observe. Radio astronomy provides the best tools to measure magnetic fields: synchrotron radiation traces fields illuminated by cosmic-ray electrons, while Faraday rotation and(More)