Related papers: The properties of Galactic globular cluster sub-sy…

We analyze post-refurbishment Hubble Space Telescope images of four globular clusters in M31. The ability to resolve stars to below the horizontal branch permits us to use star counts to extend the surface brightness profiles determined…

M54 is the central cluster of the Sagittarius dwarf galaxy. This stellar system is now in process of being disrupted by the tidal interaction with the Milky Way and represents one of the building blocks of the Galactic Halo. Recent…

The relics of building blocks that made stellar halo and bulge are yet to be discovered unless they were completely disrupted throughout the history of the Galaxy. Here we suggest that about 25% of the Milky Way globular clusters have…

We investigate the connection between globular clusters and ultra-compact dwarf galaxies (UCDs) by examining the properties of several compact objects associated with M87, all of which were previously classified as globular clusters.…

Halo globular clusters pose four succinct issues that must be solved in any scenario of their formation: single-age, single metallicity stellar populations; a lower limit ([Fe/H] ~ -2.3) to their average metallicity; comprising only 1% of…

According to the current cosmological cold dark matter paradigm, the Galactic halo could have been the result of the assemblage of smaller structures. Here we explore the hypothesis that the classical and ultra-faint dwarf spheroidal…

We present a study of the globular cluster (GC) systems of nearby elliptical and S0 galaxies at a variety of wavelengths from the X-ray to the infrared. Our analysis shows that roughly half of the low mass X-ray binaries (LMXBs), that are…

In hierarchical galaxy formation the stellar halos of galaxies are formed by the accretion of minor satellites and therefore contain valuable information about the (early) assembly process of galaxies. Our GHOSTS survey measures the stellar…

We propose that the observed stellar halo around the globular cluster (GC) NGC 1851 is evidence for its formation in the central region of its defunct host dwarf galaxy. We numerically investigate the long-term dynamical evolution of a…

We investigated the globular cluster system of the S0 galaxy NGC 1380 in the Fornax cluster with deep BVR photometry. We identified two, presumably old, populations of globular clusters. The blue globular clusters seem to be counterparts to…

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…

The globular clusters (GC) of our Galaxy have been found to lie close to a plane in the log(R_e), log(sigma), SB_e space, on the continuation of the Fundamental Plane (FP) known to characterize the properties of early-type galaxies. We…

M31 hosts a rich population of outer halo ($R_{\rm{proj}} > 25$ kpc) globular clusters (GCs), many of which show strong evidence for spatial and/or kinematical associations with large-scale tidal debris features. We present deep Hubble…

New age determinations of the galactic disk globular clusters 47 Tuc, M71 and NGC6352 have been performed with our up-to-date alpha-enhanced stellar models. We find that all three clusters are about 9.2 Gyr old and therefore coeval with the…

Theoretical integrated broad-band colors ranging from far-UV to near-IR have been computed for old stellar systems from our evolutionary population synthesis code. These models take into account, for the first time, the detailed systematic…

Most Globular Clusters (GC) show chemical inhomogeneities in the composition of their stars, apparently due to a second stellar generation (SG) in which the forming gas is enriched by hot-CNO cycled material processed in stars belonging to…

Old, metal-poor globular clusters trace the formation and evolution of early-type galaxies. Their are the best probes, at low redshift, of the building-up of galaxy halos at high redshift. Their properties constrain the characteristics of…

The connection between a galaxy's total globular cluster system (GCS) mass and its halo mass has been studied for decades and it has been found that galaxies at nearly all observed masses adhere to a linear scaling relation between these…

We use 666 blue horizontal branch (BHB) stars from the 2Qz redshift survey to map the Galactic halo in four dimensions (position, distance and velocity). We find that the halo extends to at least 100 kpc in Galactocentric distance, and…

The globular cluster HP1 is projected on the bulge, very close to the Galactic center. The Multi-Conjugate Adaptive Optics (MCAO) Demonstrator (MAD) at the Very Large Telescope (VLT) allowed to acquire high resolution deep images that,…