This paper describes results obtained on a simulation of two high-velocity encounters of NGC 4782/4783 and NGC 2672/2673 binary elliptical galaxies which differ substantially in mass ratio (about 1 for the first pair, and about 10 for the second). CCD images and velocities obtained from digital spectra were used to constrain simulations of the

Observations of a broad area at the core of M82, obtained with spatial resolution 30 arcsec and velocity resolution 15.6 km/sec in the J = 2-1 line of CO using the 12-m NRAO antenna at KPNO, are reported. The data are presented in graphs and contour maps and characterized in detail. It is found that the J = 2-1 map is similar to the J = 1-0 map of

A method to explore the column density of the Local Interstellar Medium (LISM) using absorptions in the resonance H and K lines of Mg II. The intrinsic strengths of these lines in the temperature and density conditions prevailing in warm clouds in the LISM allows them to be used to explore many lines of sight where lines such a NaD and Ca II H and

The general solution for the birth function B(m,t) of stars, derived by Casuso et al. (1989) was used to obtain a first-order analytical approximation to this function as a function of metallicity Z. This approximation was used to obtain a fit to the observational curve compiled by Tinsley (1980) for the cumulative function of stars with

An observational test of the binary hypothesis for the origin of the blue straggler (BS) stars has been performed searching for radial velocity variables among 27 BS in five galactic clusters. The significance of the BS phenomenon for the interpretation of evolutionary synthesis models and the spectra of elliptical galaxies is briefly discussed.

Given observed equivalent widths of Mg II and Mg I absorptions due to an interstellar cloud in which a late-B star is embedded, it is shown that the basic physical parameters (kinetic temperature, mean density, electron density, and radius) can be constrained. Hydrogen ionization by means of cosmic rays and the effect of the stellar radiation field