We consistently analyse for the first time the impact of survey depth and spatial resolution on the most used morphological parameters for classifying galaxies through non-parametric methods: Abraham and Conselice-Bershady concentration indices, Gini, M20 moment of light, asymmetry, and smoothness. Three different non-local data sets are used

The solar abundances of Fe and of the CNO elements play an important role in addressing a number of important issues such as the formation, structure, and evolution of the Sun and the solar system, the origin of the chemical elements, and the evolution of stars and galaxies. Despite the large number of papers published on this issue, debates about

We present deep Gemini Multi-Object Spectrograph-South optical broad-band images for a complete sample of 20 Sloan Digital Sky Survey selected type II quasars taken from Zakamska et al., with redshifts in the range 0.3 z 0.41 and [O III]λ5007 emission-line luminosities L[O iii ]>108.5 L . The images were taken with the aim of investigating the

It is shown how present uncertainties in the ability to compute collisional cross sections for rotational transitions can lead to order of magnitude errors in the interpretation of the observed antenna temperatures for rotational emission lines from interstellar clouds. The framework within which improved cross sections can be derived is described

We investigate recent claims that the Hubble sequence of spiral galaxies is scale-free. Fundamental to this investigation is the fact that within the photometric data of 86 spiral galaxies from de Jong & van der Kruit-from which these claims were made-a trend exists between morphological type and bulge profile shape. While late-type spiral bulges

We study the influence of gravitational microlensing on the spectral line profiles originating from a relativistic accretion disc. Using the Chen & Halpern model for the disc, we show the noticeable changes that microlensing can induce in the line shape when the Einstein radius associated with the microlens is of a size comparable to that of the