The observations of the low-mass x ray binary, Cyg X-2, taken with the International Ultraviolet Explorer (IUE) in a campaign conducted in June and October of 1988 are reported. A direct relationship between the strength of the UV continuum and line emission and the placement of the x ray spectrum in one of three branches of the so-called Z-shaped

A sensitive observing system for observing the cosmic microwave background on an angular scale of 8 deg is described. This angular scale is appropriate for studies of intrinsic fluctuations in the CMB generated by gravitational potential fluctuations (the Sachs-Wolfe effect). The beam-switching system employs low-noise and broadband cryogenically

An automatic and fast procedure was implemented to determine Te and log g from the comparison of the UV S 2/68 spectra with the Kurucz models. The method has been applied to all A and F stars with (B-V)0 greater than or equal to 0 and luminosity classes III, IV, IV-V, and V, included in the Ultraviolet Bright-Star Spectrophotometric Catalogue. From

Open clusters have long been used to study the chemodynamical evolution of the Galactic disc. This requires a homogeneously analysed sample covering a wide range of ages and distances. In this paper, we present the Open Clusters Chemical Abundances from Spanish Observatories (OCCASO) second data release. This comprises a sample of high-resolution

We investigate the influence of scattering processes in the continuum on the formation of lines in static, one dimensional atmosphere. It is shown that the Schuster mechanism of emission line formation can work under certain physical conditions. We derive formulae for the calculation of the line profiles in atmospheres with an ad hoc temperature

Ultra-compact nuclear rings (UCNRs) can be defined as those galactic circumnuclear rings with a radius inferior to 200 parsecs [1]. Because very high spatial resolution is needed, this population has not been studied systematically until now. One important issue that has to be solved is whether UCNRs have an origin similar to larger circumnuclear