We have compiled a catalogue of light curve solutions of contact binary stars. It contains the results of 159 light curve solutions. The properties of contact binary stars were studied using the catalogue data. As is well known since Lucy's (\cite{Lucy68a},b) and Mochnacki's (\cite{Mochnacki81}) studies, primary components transfer their own energy

We have obtained both virial and dynamical masses of a sample oflocal star forming galaxies from the UCM survey. The rotational curvesmeasured using the kinematics of the ionized gas where used as tracersof the mass of the system. The goal is to obtain a relationship with fotometric stellar masses,calculated from population synthesis models, in

This thesis is made of three main parts. In the first one a sample of 55 galaxies with an active nucleus (Seyfert 1, Seyfert2 and LINERs) is analysed; these were observed with the 4.2m WHT and 1m JKT in CCD narrow band H-alpha +[NII] and [OIII] to map the distribution of HII regions and the morphology of the circumnuclear extended emission

Microvariations probe the physics and internal structure of quasars. Unpredictability and small flux variations make this phenomenon elusive and difficult to detect. Variance-based probes such as the C and F tests, or a combination of both, are popular methods to compare the light curves of the quasar and a comparison star. Recently, detection

Recently, several efforts have been made to identify the seismic signatures of flares and magnetic activity in the Sun and Sun-like stars. In this work, we have analysed the disc-integrated velocity and intensity observations of the Sun obtained from the Global Oscillations at Low Frequencies (GOLF) and Variability of solar IRradiance and Gravity

We investigate the structure in depth of a sunspot penumbra by means of the inversion code of the radiative transfer equation proposed by Ruiz Cobo & del Toro Iniesta (1992), applied to a set of filtergrams of a sunspot, scanning the Fe I line at 5576.1 A, with a sampling interval of 30 mA, from -120 to 120 mA from line center (data previously