We present bidimensional spectroscopy of the circumnuclear region of the Seyfert galaxy NGC 3227. The physical and kinematical characteristics of the two gaseous components reported recently by Mediavilla & Arribas are discussed. One of the components seems to be directly related to activity. We propose that it represents gas streaming from the

Context. In the era of massive spectroscopy surveys, automated stellar parameter pipelines and their validation are extremely important for an efficient scientific exploitation of the spectra. Aims: We undertake a critical and comprehensive comparison of the radial velocities and the main stellar atmosphere parameters for stars in common between

We present a study of the properties of radial conformal Killing fields (RCKF) in conformally flat space-times, pointing out its interest in kinematical cosmology. i) Robertson-Walker space-times are characterized as those conformally flat metrics admitting a geodesic RCKF. ii) The conformal factor of space-times that admit a RCKF with homogeneous

A new empirical model that accurately describes the inner and outer light-profiles of early-type galaxies is presented. This model effectively unites the Sérsic and Nuker models, and in so doing allows one to perform meaningful comparisons between the inner and outer properties of early-type galaxies. New and fundamental connections between a

Clusters of galaxies are the largest known gravitationally bound structures in the Universe, with masses around 1015 M⊙, most of it in the form of dark matter. The ground-based Imaging Atmospheric Cherenkov Telescope MAGIC made a deep survey of the Perseus cluster of galaxies using almost 400 h of data recorded between 2009 and 2017. This is the

Context. The chemical composition of stars that have orbiting planets provides important clues about the frequency, architecture, and composition of exoplanet systems. Aims: We explore the possibility that stars from different galactic populations that have different intrinsic abundance ratios may produce planets with a different overall