A 16-min time series of two-dimensional "Multichanel Subtractive Double Pass" spectrograms, recorded in the NaD_2_ 5690 line, has been used to study the vertical structure of the photosphere and, in particular, the penetration of granules. A statistical and a morphological investigations have been made. The 5-min oscillations have been carefully

This paper summarizes the common properties of the currently known galactic black hole candidates. Particular emphasis is given to optical studies of the best candidates (those soft X-ray transients with dynamical evidence) and the problem of the mass determination. The technique used to achieve this goal (which has been applied to A0620-00, GS2023

IAUC 6131 available at Central Bureau for Astronomical Telegrams.

In this paper we propose a method for interpolating multidimensional unbinned data, which could also be sparse, using artificial neural network techniques. An artificial example is first presented in order to show the reliability and potential of the neural network interpolator. A robust behavior is found. We apply the technique to the mapping of a

Long-slit spectroscopy at four position angles is performed on the spiral NGC 5055. The nuclear region is very bright and massive and the rotation velocity in that region has shown to be linear. The density of that region is found to be 150 times that of the average over the whole galaxy. The rotation curve outside the linear region is almost flat

We report the spectroscopic detection of the secondary star in the x-ray transient QZ Vul (=GS 2000+25). Cross-correlation of individual spectra against K-type templates yields clear velocity modulations with the 8.3 hr orbital period. From the amplitude of the radial velocity curve (520 +/- 16 km/s) we derive a mass function f(M)= 5.02 +/- 0.46