Context: The topology of penumbral magnetic fields is poorly known. The satellite Hinode has recently revealed penumbral structures of a magnetic polarity that is opposite to the main sunspot polarity. They may be direct confirmation that magnetic field lines and mass flows return to the solar interior throughout the penumbra, a configuration

In this contribution we examine the problem of inferring ages and initial cluster masses from synthesis models at the limit of low-mass clusters ( M≤ a few ×104 M⊙). We show that it is not possible to apply directly synthesis models using standard methods to such clusters, since the basic hypothesis implicit in the models (a fixed proportionality

We show how inferences of the solar internal rotation rate depend on different aspects of the mode fitting procedure. We study the stability of the rotation rate and its variation with time through inversions of frequency splittings data sets computed from fitting 364, 728 and 2088-day long Michelson Doppler Imager (MDI) time series, 72-day long

We test the theoretical prediction that the straightest dust lanes in bars are found in strongly barred galaxies, or more specifically, that the degree of curvature of the dust lanes is inversely proportional to the strength of the bar. The test uses archival images of barred galaxies for which a reliable nonaxisymmetric torque parameter (Q b) and

We present comparison of numerical simulation results of MHD wave propagation in two different magnitostatic models of sunspots refferred to as "deep" and "shallow" models. The "deep" model has convex shape of magnetic field lines near the photosphere and non-zero horizorntal perturbations of the sound speed up to the bottom of the model (7.5 Mm)

We present an integral field spectroscopic study of the central 2 × 2 kpc2 of the blue compact dwarf galaxy Mrk 409, observed with the Potsdam MultiAperture Spectrophotometer (PMAS). This study focuses on the morphology, two-dimensional chemical abundance pattern, excitation properties, and kinematics of the ionized interstellar medium in the