We discuss the possibility that the extended structures, lacking young stars, routinely found in dwarf irregular galaxies (dIrr) are a consequence of a progressive shrinking of the star forming region. This would be an alternative scenario to the possible halo-disk structure of dIrr. Although the final answer must wait until kinematical data of

The interstellar medium of early type galaxies has attracted a great deal of interest ever since Faber & Gallagher (1976) showed that a considerable amount of mass ejected by evolved stars could pile up over the lifetime of the galaxy (10^8 - 10^9 M[ scriptstyle sun ]). Surprisingly though, high resolution and sensitive HI observations demonstrated

La tesis doctoral presentada por Antonio Marín, trata sobre la técnica de las fluctuaciones de brillo superficial. Se fundamenta en el estudio detallado de una fuente de varianza concreta. A partir del análisis de la varicuza se puede obtener propiedades de la población de los objetos bajo estudio. Los campos astrofísicos a los cuales se ha

We investigate the constraints on basic cosmological parameters set by the first compact-configuration observations of the Very Small Array (VSA), and other cosmological data sets, in the standard inflationary ΛCDM model. Using the weak priors 40 H0 90 km s-1 Mpc-1 and 0 τ 0.5, we find that the VSA and COBE-DMR data alone produce the

We present the power spectrum of the fluctuations in the cosmic microwave background detected by the Very Small Array (VSA) in its first season of observations in its compact configuration. We find clear detections of first and second acoustic peaks at l~ 200 and ~550, plus detection of power on scales up to l= 800. The VSA power spectrum is in

We have observed the cosmic microwave background (CMB) temperature fluctuations in eight fields covering three separated areas of sky with the Very Small Array at 34 GHz. A total area of 101 square degrees has been imaged, with sensitivity on angular scales of (equivalent to angular multipoles l= 150-900). We describe the field selection and