Optical spectroscopy of the highly collimated bipolar nebulae He 2-25, Th 2-B and 19W32 is presented. He 2-25 and Th 2-B are found to have very dense (N_e~10^7 cm^-3) cores characterized by emission lines of low- to intermediate-ionization species, including rich [FeII] emission. The Hα profiles present broad non-Gaussian wings. These spectral

Context: Observations at 0.1 arcsec have revealed the existence of dark cores in the bright filaments of sunspot penumbrae. Expectations are high that such dark-cored filaments are the basic building blocks of the penumbra, but their nature remains unknown. Aims: We investigate the origin of dark cores in penumbral filaments and the surplus

The selection from available commercial market of a set of slides to be used in an habitable pressurised module in space, to draw a 660 mm box out of a rack, up to a completely extracted position in a safely supported configuration, seems in principle not to be a complicated task. That was the first approach taken in the design process of the

Context. In the solar atmosphere, the acoustic cutoff frequency is a local quantity that depends on atmospheric height. It separates low-frequency evanescent waves from high-frequency propagating waves. Aims: We measure the cutoff frequency of slow magnetoacoustic waves at various heights of a sunspot umbra and compare the results with the

The splitting of the frequencies of the global resonant acoustic modes of the Sun by large-scale flows and rotation permits study of the variation of angular velocity Omega with both radius and latitude within the turbulent convection zone and the deeper radiative interior. The nearly uninterrupted Doppler imaging observations, provided by the

Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ~ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg2 of the Cosmic Evolution Survey. The 3077 DOGs have