Léo Girardi

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The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All the data from SDSS-III are now made public. In particular,(More)
We provide tables of theoretical isochrones in several photometric systems. To this aim, the following steps are followed: (1) First, we re-write the formalism for converting synthetic stellar spectra into tables of bolometric corrections. The resulting formulas can be applied to any photometric system, provided that the zeropoints are specified by means of(More)
The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the Tenth Public Data Release (DR10) from its current incarnation, SDSS-III. This data release includes the first spectroscopic data from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with spectroscopic data from the Baryon Oscillation(More)
We present a large set of theoretical isochrones, whose distinctive features mostly reside on the greatly improved treatment of the thermally pulsing asymptotic giant branch (TP-AGB) phase. Essentially, we have coupled the TP-AGB tracks described in Paper I, at their stages of pre-flash quiescent H-shell burning, with the evolutionary tracks for the(More)
We present the detailed spectroscopic analysis of 72 evolved stars, which were previously studied for accurate radial velocity variations. Using one Hyades giant and another well studied star as the reference abundance, we determine the [Fe/H] for the whole sample. These metallicities, together with the T eff values and the absolute V-band magnitude derived(More)
Abstract. We study classical disk clusters at nearly solar metallicity with ages in the range 200 Myr – 6 Gyr using 2MASS photometry and theoretical isochrones. As a first step we employ J, H and K Johnson’s Padova isochrones which, on a large scale, result in a good fit of the observed data. However, we find some significant deviations, especially in the(More)
We present a large grid of stellar evolutionary tracks, which are suitable to modelling star clusters and galaxies by means of population synthesis. The tracks are presented for the initial chemical compositions [Z = 0.0004, Y = 0.23], [Z = 0.001, Y = 0.23], [Z = 0.004, Y = 0.24], [Z = 0.008, Y = 0.25], [Z = 0.019, Y = 0.273] (solar composition), and [Z =(More)
Context. In many astrophysical contexts, the helium content of stars may differ significantly from those usually assumed in evolutionary calculations. Aims. In order to improve upon this situation, we have computed tracks and isochrones in the range of initial masses 0.15 − 20M ⊙ for a grid of 39 chemical compositions with the metal content Z between 0.0001(More)
We briefly review the main features in the broad-band colour evolution of star clusters, over the complete age interval from 10 to 10 yr. The emphasis is in the problem of age-dating distant young clusters (∼< 2 Gyr) from their integrated colours. It is shown that U−B and B−V are less sensitive to metallicity than colours involving red passbands, like V −I,(More)
The aim of this paper is to cast light on the formation and evolution of elliptical galaxies by means of N-body/hydro-dynamical simulations that include star formation, feed-back and chemical evolution. Particular attention is paid to the case of dwarf spheroidals of the Local Group which, thanks to their proximity and modern ground-based and space(More)