We determine the extinction curve in the zl=0.83 lens galaxy of the gravitational lens SBS 0909+532 from the wavelength dependence of the flux ratio between the lensed quasar images (zs=1.38) from 3400 to 9200 Å. It is the first measurement of an extinction curve at a cosmological distance of comparable quality to those obtained within the Galaxy

Doppler velocities in the penumbra of a δ-configuration sunspot observed near the limb indicate flows that converge upon the line separating locally positive and negative polarity magnetic field (the polarity inversion line). These flows persist for many hours. Observations of this region with the Advanced Stokes Polarimeter (ASP) reveal a convex

We have studied the Balmer line shapes of NGC 3516 in order to find the structure of central Emission Line Region (ELR) and the physical parameters of the emitting plasma. The shapes of these broad emission lines show evidences of a multicomponent origin and also features which could be identified as the peaks of a rotating disc. We have proposed a

In the present work, we study correlations between stellar fundamental parameters and the oscillation amplitude for delta Scuti stars. We present this study for a sample of 17 selected delta Scutis belonging to 5 young open clusters. Taking advantage of properties of delta Scutis in clusters, we correct the photometric parameters of our objects for

With over 5 years of GOLF data having some 90% continuity, a new attempt has been made to search for possible solar g modes. Statistical methods are used, based on the minimum of assumptions regarding the solar physics; namely that mode line-widths are small compared with the inverse of the observing time, and that modes are sought in the frequency

El estudio de propiedades de la granulación y las fáculas del centro al borde del disco es un tema clásico en Física Solar. Aunque se ha dedicado mucho trabajo observacional, semi-empírico y teórico a este asunto, todavía no existe acuerdo generalizado sobre el escenario físico adecuado para reproducir los numerosos observables medidos en diversas