We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and HeI lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. HeII absorptions and metal lines (including many selective emission lines but excluding HeII λ4686 Å emission) are essentially

Understanding the complicated non-linear thermal and magnetodynamic processes observed to continuously reshape the solar atmosphere requires the use of three-dimensional computer simulations and numerical experimentation. In this paper, a number of results from the recent generation of 3D numerical models of magnetic flux emergence from the topmost

We present results from SEPPCoN (Survey of Ensemble Physical Properties of Cometary Nuclei), a survey of 100 Jupiter-family comets (JFCs) using the Spitzer Space Telescope for mid-infrared measurements of thermal emission and several ground-based telescopes for visible-wavelength measurements of reflected sunlight. Our sample represents about 30%

The analysis of the X-ray data for a sample of 51 LINER nuclei with available X-ray Chandra imaging is reported. Our aim was to investigate the physical mechanisms which power LINER nuclear activity. The use of multiwavelenght information at radio, UV, optical HST and X-ray lead us to conclude that at least 60% of the LINERs are hosting a low

We present the possible use of spectro-polarimetric measurements on a set of data recorded with La Palma Stokes Polarimeter attached to the Swedish Vacuum Solar Telescope. The stratification over the solar atmosphere of different physical parameters is retrieved from these data using the Stokes Inversion based on Response functions (SIR). We derive

Genuine spectral energy distributions (SED) of the central few parsec region of the nearest and brightest active galaxies in the southern hemisphere are presented. These are compiled from very high-spatial resolution data taken from radio (VLBA), IR adaptive optics and interferometry, and optical (HST) observations. The new SEDs are characterized