Related papers: Helium variations in Galactic and extragalactic Gl…
We build on the evidence provided by our Legacy Survey of Galactic globular clusters (GC) to submit to a crucial test four scenarios currently entertained for the formation of multiple stellar generations in GCs. The observational…
The study of star clusters plays an important role in our understanding of the Universe since these systems are natural laboratories for testing theories of stellar dynamics and evolution. Particularly, globular clusters (GCs) are one of…
We present new UV observations for NGC288, taken with the WFC3 detector on board the Hubble Space Telescope, and combine them with existing optical data from the archive to explore the multiple-population phenomenon in this globular cluster…
Black holes (BHs) play a major role in the structural and dynamical evolutions of Globular Clusters (GCs). Several recent works searched for BHs in Galactic GCs using scaling relations derived from numerical simulations. However, the…
(abridged) Recent spectroscopic and photometric observations show the existence of various generations of stars in GCs, differing in the abundances of products of H-burning at high temperatures (the main final product being He). It is…
Stars in globular clusters (GCs) lose a non negligible amount of mass during their post-main sequence evolution. This material is then expected to build up a substantial intra-cluster medium (ICM) within the GC. However, the observed gas…
Nearly all of the well studied ancient globular clusters (GCs), in the Milky Way and in nearby galaxies, show star-to-star variations in specific elements (e.g., He, C, N, O, Na, Al), known as "multiple populations" (MPs). However, MPs are…
While chemical composition spreads are now believed to be a universal characteristic of globular clusters (GCs), not all of them present multiple populations in their color-magnitude diagrams (CMDs). Here we present a new scenario for the…
We present an overview of observational progress in the study of extragalactic globular cluster systems. Globular clusters turn out to be excellent tracers not only for the star-formation histories in galaxies, but also for kinematics at…
We summarize some observational comparison concerning the features of globular clusters (GCs) population in connection to the evolution of King models. We also make a comparison with some extragalactic GCs systems, in order to underline the…
The Halo Galactic Globular Clusters (GCs) lying inside the solar circle (\inn, \r $< 8 Kpc$, \feh$<-0.8$) are shown to keep no record of the strong correlation between GC absolute integrated magnitudes and core parameters (concentration and…
An increasing number of both photometric and spectroscopic observations over the last years have shown the existence of distinct sub-populations in many Galactic globular clusters and shattered the paradigm of globulars hosting single,…
Lithium is created during the Big Bang nucleosynthesis and it is destroyed in stellar interiors at relatively low temperatures. However, it should be preserved in the stellar envelopes of unevolved stars and progressively diluted during…
Recent observations have revealed that at least 8 globular clusters (GCs) in the Galaxy show internal abundance spreads in [Fe/H]. We investigate the origin of these `anomalous' GCs using numerical simulations of GCs in the dwarfs orbiting…
Most inhomogeneities in the chemical composition of GC stars are due to primordial enrichment. The model today most credited is that the winds lost by high mass Asymptotic Giant Branch (AGB) stars, evolving during the first $\simlt$200Myr…
Variations in the number of globular clusters per unit galaxy luminosity, which is the specific frequency, and the mass of globular clusters per unit total available mass, are reviewed. Correlations with galaxy luminosity and morphology,…
Recent stellar evolution models for globular clusters (GCs) in multiple population paradigm suggest that horizontal-branch (HB) morphology and mean period of type ab RR Lyrae variables are mostly determined by He & CNO abundances and…
Galactic globular cluster stars exhibit abundance patterns which are not shared by their field counterparts. It is clear from recent spectroscopic observations of GC turnoff stars that these abundance anomalies were already present in the…
Recent observations have reported that the Galactic globular clusters (GCs) with unusually extended horizontal-branch (EHB) morphologies show a significantly lower velocity dispersion compared with that of the entire Galactic GC system. We…
Star-to-star variations in abundances of the light elements carbon, nitrogen, oxygen, and sodium have been observed in stars of all evolutionary phases in all Galactic globular clusters that have been thoroughly studied. The data available…