We develop a method for computing the probability densities of spherical voids in distribution of galaxies on a large scale. This method is applied to Poissonian cluster models. We consider CDM biased and non-biased models; the appropriate approximation has been used in each case. We find that, in the latter case, the probability finding a void

We have made a series of hydrodynamic calculations of core collapsing models to examine the effects of temperature dependence of nuclear compressibility. With this aim we have focused on the influence of the equation of state derived by Viñas et al. for two extreme types of nuclear interactions. A Multigroup Trapping Scheme for neutrino transport

A representative set of profiles is presented for the Ca II H resonace line in Stokes V and I, for the quiet sun, plages, sunspot umbrae, and a flare, as well as one example of the Ca II K line in a sunspot penumbra. The degree of polarization is highest in the spots and zero in the quiet sun, within error limits. The V profile asymmetries are

A study is presented of the internal velocity structure of NGC 3656, a galaxy with several morphological signatures of being in an advanced merger stage. Rotation curves obtained for two slit-position angles show that the inner 1 kpc rotates around an axis roughly perpendicular to the rotation axis in the main body of the galaxy. There are

This paper presents near-infrared monitoring, taken with the 1.5 m Carlos Sanchez Telescope in Tenerife and CCD photometry taken with the Jacobus Kapteyn Telescope in La Palma, of the 1988 outburst of 3C 279. This is combined with archival data to examine the behavior of the light curve from B to K.

A brief description of the HEXAFLEX system is presented, which has been contrived to carry out two-dimensional spectroscopy (spectral imaging) in combination with the FLEX spectrograph at the 4.2 m William Herschel Telescope. Some astronomical illustrative examples are shown.