Related papers: Dynamo-generated magnetic fields in fast rotating …
We present the results of a search for unusually rapidly rotating giant stars in a large sample of K giants (~1300 stars) that had been spectroscopically monitored as potential targets for the Space Interferometry Mission's Astrometric…
The observed galactic magnetic fields may have a primordial origin. I briefly review the observations, their interpretation in terms of the dynamo theory, and the current limits on cosmological magnetic fields. Several possible mechanisms…
Internal stellar magnetic fields are inaccessible to direct observations and little is known about their amplitude, geometry and evolution. We demonstrate that strong magnetic fields in the cores of red giant stars can be identified with…
About 10% of hot stars host a fossil magnetic field on the pre-main sequence and main sequence. However, the first magnetic evolved hot stars have been discovered only recently. An observing program has been set up to find more such…
Recent numerical simulations by Freytag et al. of the outer convection envelope of the cool super-giant Betelgeuse, have shown that the fluctuations in the star's apparent luminosity may be caused by giant cell convection. These simulations…
We explore the amplification of magnetic fields in the high-redshift Universe. For this purpose, we perform high-resolution cosmological simulations following the formation of primordial halos with \sim10^7 M_solar, revealing the presence…
The origin of large-scale magnetic fields, detected in some low-mass (dwarf and irregular) galaxies via polarised synchrotron emission and Faraday rotation, remained unexplained for a long time. We suggest that mean-field dynamo can be…
Direct measurements of magnetic fields in low-mass stars of spectral class M have become available during the last years. This contribution summarizes the data available on direct magnetic measurements in M dwarfs from Zeeman analysis in…
The origin of magnetic fields in isolated and binary white dwarfs has been investigated in a series of recent papers. One proposal is that magnetic fields are generated through an alpha-omega dynamo during common envelope evolution. Here we…
Observations of red (G-K)-giant stars with the CoRoT satellite provide unprecedented information on the stochastically excited oscillations in these stars. The long time series of nearly uninterrupted high-cadence and high-precision…
The magnetic fields of spiral galaxies are so strong that they cannot be primordial. Their typical values are over one billion times higher than any value predicted for the early Universe. Explaining this immense growth and incorporating it…
During the last decade and a half, the new generation spectropolarimeter Narval at Pic du Midi, France allowed the study of weak magnetic fields in cool giant stars that are fairly evolved after main sequence. We present a short summary on…
Magnetic fields pervade astrophysical systems and strongly influence their dynamics. Because magnetic diffusion is usually much faster than system evolution, ancient fields cannot explain the present magnetization of planets, stars, and…
Several lines of evidence suggest that protogalactic and galactic environments manage to grow magnetic field very rapidly. This makes the theoretical problem of achieving rapid growth of magnetic fields in such environments difficult.…
(abridged) We investigate the possibility to recognize the magnetic field structures in nearby galaxies and to test the cosmological evolution of their large- and small-scale magnetic fields with the SKA and its precursors. We estimate the…
Magnetic fields generated by a dynamo mechanism due to differential rotation during stellar mergers are often proposed as an explanation for the presence of strong fields in certain classes of magnetic stars, including high field magnetic…
Dynamo action in fully convective stars is a debated issue that also questions our understanding of magnetic field generation in partly convective Sun-like stars. During the past few years, spectropolari- metric observations have…
The origin and the magnitude of the inter-galactic magnetic field is of primordial importance in the global picture of magnetic field evolution, as it is considered to be the missing link between galactic magnetic fields and cluster…
Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to amplification of a small seed field by a turbulent galactic dynamo. We critically review the current status of the galactic…
Our theoretical and numerical analysis have suggested that for low-mass main sequences stars (of the spectral classes from M5 to G0) rotating much faster than the Sun, the generated large-scale magnetic field is caused by the mean-field…