The Milky Way and the Local Group (MWLG)
  • Publication
    On the Metamorphosis of the Bailey Diagram for RR Lyrae Stars
    We collected over 6000 high-resolution spectra of four dozen field RR Lyrae (RRL) variables pulsating either in the fundamental (39 RRab) or in the first...
  • Publication
    On the missing second generation AGB stars in NGC 6752
    In recent years the view of Galactic globular clusters as simple stellar populations has changed dramatically, it is now thought that basically all globular...
  • Publication
    On the most luminous planetary nebulae of M 31
    Context. The planetary nebula luminosity function (PNLF) is a standard candle that comprises a key rung on the extragalactic distance ladder. The method is...
  • Publication
    On the nature of candidate luminous blue variables in M 33
    Context. Luminous blue variables (LBVs) are a class of highly unstable stars that have been proposed to play a critical role in massive stellar evolution as...
  • Publication
    On the non-evolution of the dependence of black hole masses on bolometric luminosities for QSOs
    There are extremely luminous quasi stellar objects (QSOs) at high redshift which are absent at low redshift. The lower luminosities at low redshifts can be...
  • Publication
    On the post-common-envelope central star of the planetary nebula NGC 2346
    The common-envelope phase is one of the most poorly understood phases of (binary) stellar evolution, in spite of its importance in the formation of a wide range...
  • Publication
    On the Presence of Metallofullerenes in Fullerene-rich Circumstellar Envelopes
    The presence of neutral C 60 fullerenes in circumstellar environments has been firmly established by astronomical observations as well as laboratory experiments...
  • Publication
    On the radial abundance gradients of nitrogen and oxygen in the inner Galactic disc
    We present optical spectra of nine Galactic H II regions observed with the 10.4 m Gran Telescopio Canarias telescope and located at Galactocentric distances (R...
  • Publication
    On the Radial Distribution of Horizontal Branch Stars in NGC 2808
    We present accurate new ultraviolet and optical BVI photometry for the Galactic globular cluster NGC 2808 based on both ground-based and archival Hubble Space...