Dark Matter supposedly dominates the extragalactic Universe, yet no totally dark structure of galactic proportions has ever been convincingly identified. Minchin et al. (2005) suggested that VIRGOHI 21, a 21-cm source found in the Virgo Cluster by Davies et al. (2004), was probably such a dark galaxy because of its broad line-width ( ˜ 200 km s-1)

We analyze the Hα emission line profiles of the HII region populations in three disc spiral galaxies and find evidence of wing features at 40-90 km/s from the central peak in a significant fraction of regions. We explain the wing features as due to a shell expanding inside the HII region, quantify the energy involved and present two possible

We present a discussion of efforts to obtain external validation of the estimated atmospheric parameters (Teff, log g, [Fe/H]) obtained from medium-resolution (R = 2000) SDSS spectroscopy and ugriz photometry, which are being employed for both the completed SDSS-I and the ongoing SEGUE survey. The SDSS/SEGUE spectroscopic pipeline makes use of a

This communication reviews some of the most challenging topics in high-resolution ground-based Solar Physics. The most powerful European facilities are described, together with their capabilities and skills gained in Europe using them. The reasons for a large-aperture solar telescope are outlined, based on present scientific needs, which have led

We present first comparisons between high resolution observations of the quiet photosphere, obtained with the Interferometric BIdimensional Spectrometer (IBIS) in the non-magnetic Fe I 7090.4 Å spectral line, and the synthetic spectrum calculated for a 3D snapshot of a radiation-hydrodynamical simulation of the solar atmosphere. Together with

We investigate signatures of siphon flows in a region around a solar magnetic pore, observed in the photosphere at μ = 0.6, during its decay phase. We analyze high-resolution Stokes spectra acquired by Hinode/Solar Optical Telescope along the Fe I pair at 630.2 nm. We determine the vector magnetic field and the line-of-sight velocity by an