A Fourier analysis of the intensity distribution in the planes of nine spiral galaxies is performed. In terms of the arm classification scheme of cite[Elmegreen & Elmegreen (1987)]{ee87} seven of the galaxies have well-defined arms (classes 12 and 9) and two have intermediate-type arms (class 5). The galaxies studied are NGC 157, 753, 895, 4321

Time series of high-resolution white-light images of six solar pores, observed in 1993 and 1995 at the Swedish Vacuum Solar Telescope (La Palma), are analyzed. The pores constitute an almost ideal laboratory in which to study the interaction of a vertical magnetic field with surrounding convective motions, without the perturbation of the inclined

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We have performed a study of the influence of the environment on the rate of star formation (SFR) in a sample of galaxies in nearby compact groups. The sample has been chosen from the Catalog of Hickson Compact Groups of Galaxies. High‐quality Hα images of the sample of galaxies in 16 compact groups were obtained and combined with additional deep

An 800 day series of GOLF velocity data, with uniquely high continuity and stability, offers the best ever signal to noise ratio obtained in global Sun observations. Following meticulous efforts to provide reliable calibration, these data have been used for measurements of frequencies, line-widths and power in the p-modes, which are used for

In an attempt to assess the physical realism of the plage flux tube model derived by Bellot Rubio, Ruiz Cobo & Collados (cite{brc}, cite{bellot}) we extend its predictions to the Stokes V zero-crossing shifts of a number of Fe ii lines. For this analysis, accurate Fe ii central wavelengths are required. We have devised a procedure for bringing the