Novel spectropolarimetric observations of the He I multiplet are used to explore the dynamics of the chromospheric oscillation above sunspot umbrae. The results presented here provide strong evidence in support of the two-component model proposed by Socas-Navarro and coauthors. According to this model, the waves propagate only inside channels of

The analysis of the Hanle effect in solar molecular lines allows us to obtain empirical information on hidden, mixed-polarity magnetic fields at subresolution scales in the (granular) upflowing regions of the ``quiet'' solar photosphere. Here we report that collisions seem to be very efficient in depolarizing the rotational levels of MgH lines

Esta tesis presenta un análisis conjunto de los espectros ultravioleta, óptico e infrarrojo cercano de las estrellas Vega y Porción. Para los análisis se hace uso de modelos de atmósfera planoparalelos, en equilibrio termodinámico local, con el llamado efecto de line-blanketing y la aproximación de la longitud de mezcla para la convección, y

La tesis doctoral que se presenta está dedicada al estudio de un grupo de estrellas masivas calientes con espectros del telescopio Far Ultravioleta Espectroscopia Exlorer (FUSE, 905-1187A), complementados con datos de archivo del telescopio international Ultraviolet Explor (IUE) y del Hubble Space Telescope (HST) para el rango 1150-1800A. Los datos

Emission line galaxies are the most easily detected and studied objects in the high redshift Universe. They are being used to trace the evolution of critical observables of the Universe such as Star Formation Rate densities, starburst properties and abundances. Most of the research is being done using [OII]3727 and UV lines, but H α is still one

We present the final global design and performances of EMIR, the NIR multiobject spectrograph of the GTC, as well as the plan for its early scientific exploitation. EMIR, currently in the middle of its final phase, will be one of the first common user instruments for the GTC, the 10 meter telescope under construction by GRANTECAN at the Roque de