There is phenomenological evidence that magnetic reconnection operates in the interstellar medium, and magnetic reconnection is also necessary for the operation of a galactic dynamo. The extremely long ohmic di†usion times of magnetic Ðelds in typical interstellar structures suggest that reconnection occurs in two stages, with thin current layers that have relatively short resistive decay times...

Interstellar polarization from aligned dust grains can be measured both in transmission at visible and near-infrared wavelengths and in emission at far-infrared and sub-mm wavelengths. These observations can help predict the behavior of foreground contamination of CMB polarimetry by dust in the Milky Way. Fractional polarization in emission from aligned dust grains will be at the higher range o...

Almost all interstellar objects contain inherent inhomogeneity. The inhomogeneity can manifest in many different ways, such as the uneven matter distribution in a molecular cloud, or the tangled magnetic field distribution in a Bok globule. The dynamics of interstellar objects is thus often governed by the interaction between astrophysical flows or shocks such as supernova blast waves with inho...

Received ; accepted – 2 – ABSTRACT Linearly polarized, non-masing, rotational lines have been detected for the first time in the interstellar medium. This effect occurs in molecular clouds with a magnetic field, and traces the field direction, offering an alternative technique to dust emission polarimetry. The line polarization mechanism is similar to that in masers, but with lower degrees of p...

Supernovae are the dominant energy source for driving turbulence within the interstellar plasma. Until recently, their effects on magnetic field amplification in disk galaxies remained a matter of speculation. By means of self-consistent simulations of supernova-driven turbulence, we find an exponential amplification of the mean magnetic field on timescales of a few hundred million years. The r...

Pulsars provide unique probes for the large-scale interstellar magnetic field in the Galactic disk. The Parkes multibeam pulsar survey has discovered many distant pulsars which enables us for the first time to explore the magnetic field in most of the nearby half of the Galactic disk. The fields are found to be coherent in direction over a linear scale of ∼ 10 kpc between the Carina-Sagittarius...

Thermal fluctuations in the magnetization of interstellar grains will produce magnetic dipole emission at ν ∼< 100 GHz. We show how to calculate absorption and emission from small particles composed of material with magnetic as well as dielectric properties. The Kramers-Kronig relations for a dusty medium are generalized to include the possibility of magnetic grains. The magnetic permeability a...

We review the use of velocity centroids statistics to recover information of interstellar turbulence from observations. Velocity centroids have been used for a long time now to retrieve information about the scaling properties of the turbulent velocity field in the interstellar medium. We show that, while they are useful to study subsonic turbulence, they do not trace the statistics of velocity...

We present a statistical analysis of the interstellar medium (ISM) polarization from the largest compilation available of starlight data, which comprises ∼ 5500 stars. The measured correlation between the mean polarization degree and extinction indicates that ISM dust grains are not fully aligned with the uniform component of the large-scale Galactic magnetic field. Moreover, we estimate the ra...

We show that atomic alignment presents a reliable way to study topology of astrophysical magnetic fields. The effect of atomic alignment arises from modulation of the relative population of the sublevels of atomic ground state pumped by anisotropic radiation flux. As such aligned atoms precess in the external magnetic field and this affects the properties of the polarized radiation arising from...