Related papers: The `Second Parameter': A Memory from the Globular…
We investigate the structural, kinematical, and chemical properties of globular cluster systems (GCSs) in galaxies of different Hubble types in a self-consistent manner based on high-resolution cosmological N-body simulations combined with…
We have applied a new method to analyze the horizontal branch (HB) morphology in relation to the distribution of stars near the red giant branch (RGB) tip for the globular clusters M22, M5, M68, M107, M72, M92, M3 and 47 Tuc. This new…
We suggest that the majority of the "young", so--called "second parameter" globular clusters (SPGCs) have originated in the outer Galactic halo due to a process other than a tidal disruption of the dwarf spheroidal (dSph) galaxies. Basic…
We examine the photometric data for Fornax clusters, focussing our attention on their horizontal branch color distribution and, when available, on the RR Lyr variables fraction and period distribution. Based on our understanding of the HB…
We have developed an homogeneous evolutionary scenario for H- and He-burning low-mass stars by computing updated stellar models for a wide metallicity and age range (0.0002$\le Z \le$0.004 and 9$\le t(Gyr) \le$15, respectively) suitable to…
A catalog of Galactic globular clusters has been compiled and used to analyze relations between the chemical and kinematic parameters of the clusters. The catalog contains positions, distances, luminosities, metallicites, and…
We report on the discovery of gamma-ray emission from several globular clusters (GCs), including Terzan 5, the second known gamma-ray GCs. By now, more than a dozen GCs are known to emit gamma-rays of energies above 100 MeV, thus enabling…
We present new empirical estimates of the Delta V_HB_bump parameter for 15 Galactic globular clusters (GGCs) using accurate and homogeneous ground-based optical data. Together with similar evaluations available in the literature, we ended…
The observed characteristics of globular cluster (GC) systems, such as metallicity distributions, are commonly used to place constraints on galaxy formation models. However, obtaining reliable metallicity values is particularly difficult…
Observed metallicities of globular clusters reflect physical conditions in the interstellar medium of their high-redshift host galaxies. Globular cluster systems in most large galaxies display bimodal color and metallicity distributions,…
Color-magnitude diagrams from deep, wide-field CCD photometry of the Sculptor dwarf spheroidal galaxy reveal that the red horizonal branch (RHB) stars are strongly concentrated towards the center of the galaxy relative to the dominant old…
Tidally enhanced stellar wind may affect horizontal branch (HB) morphology in globular clusters (GCs) by enhancing the mass loss of primary star during binary evolution. Lei et al. (2013a, 2013b) studied the effect of this kind of wind on…
Globular cluster systems exhibit a bewildering variety of characteristics. No single scenario appears to be able to account for the wide range of specific globular cluster frequencies that are observed in galaxies of various types. The…
We discuss the present state of knowledge and thought concerning the spread in age found among Galactic globular clusters, with some discussion of the implications for what happened during the earliest stages of the formation of the Milky…
The observed properties of long gamma-ray burst (GRB) host galaxies show them to often be of a rather low metallicity and/or of high specific star formation rate (SFR). It is not clear which of these properties is a dominant factor in…
The majority of the inhomogeneities in the chemical composition of Globular Cluster (GC) stars appear due to primordial enrichment. The most studied model today claims that the ejecta of Asymptotic Giant Branch (AGB) stars of high mass…
We establish a framework for determing absolute ages of Galactic globular clusters and then use these ages to investigate the age-metallicity and age-Galactocentric distance relations for the 36 clusters with the most reliable age data. The…
We use deep, high quality colour magnitude diagrams obtained with the Hubble Space Telescope to compute a simplified version of the Mironov index [SMI; B/(B+R)] to parametrize the horizontal branch (HB) morphology for 23 globular clusters…
Metallicity is the first parameter to influence the horizontal branch (HB) morphology of globular clusters (GCs). It has been found, however, that some other parameters may also play an important role in affecting the morphology. While the…
The fraction of binary stars is an important ingredient to interpret globular cluster dynamical evolution and their stellar population. We investigate the properties of main-sequence binaries measured in a uniform photometric sample of 59…