Related papers: Horizontal branch morphology in galactic globular …

The morphology-density relationship states that dense cosmic environments such as galaxy clusters have an overabundance of quiescent elliptical galaxies, but it is unclear at which redshift this relationship is first established. We study…

[Abridged] The environment where galaxies are found heavily influences their evolution. Close groupings, like the cores of galaxy clusters or compact groups, evolve in ways far more dramatic than their isolated counterparts. We have…

Horizontal Branch stars belong to an advanced stage in the evolution of the oldest stellar galactic population, occurring either as field halo stars or grouped in globular clusters. The discovery of multiple populations in these clusters,…

Sizeable number of stellar-mass black holes (BHs) in globular clusters (GCs) can strongly influence the dynamical evolution and observational properties of their host cluster. Using results from a large set of numerical simulations, we…

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…

Atmospheric parameters (Teff, log g and log(He/H)) are derived for 42 hot horizontal branch (HB) stars in the globular cluster NGC 6752. For 19 stars MgII and FeII lines are detected indicating an iron enrichment by a factor 50 on average…

Atmospheric parameters (effective temperature Teff, surface gravity log g), masses and helium abundances are derived for 42 hot horizontal branch (HB) stars in the globular cluster NGC 6752. For 19 stars we derive magnesium and iron…

Globular Cluster (GC) Color-Magnitude Diagrams (CMDs) are reasonably well understood in terms of standard stellar-evolution. However, there are still some open issues, such as fully accounting for the Horizontal Branch (HB) morphology in…

The UV properties of old stellar populations have been subject of intense scrutiny from the late sixties, when the UV-upturn in early type galaxies was first discovered. Because of their proximity and relative simplicity, Galactic globular…

We present the results of a first global analysis of the Horizontal Branch morphology of Globular Clusters in the nearby spiral M31, based on their Color Magnitude Diagrams.

We investigate the dependences of galaxy star-formation history and galaxy morphology on environment, using color and H-alpha equivalent width as star-formation history indicators, using concentration and central surface brightness as…

The uncertainties in the modelling of some important inputs of stellar evolution must be taken into account for a correct interpretation, both of the HR diagrams of individual stars, and of the integrated colors, of stellar clusters. After…

A recent study shows, from an empirical deduction, that the number and the presence of the blue straggler stars (BSS) in an open cluster follow a function whose components are the ratio between age and the relaxation time, $\it f$, and a…

The globular cluster M79 was observed with the Hopkins Ultraviolet Telescope (HUT) during the Astro-1 space shuttle mission in 1990 December. The cluster's far-UV integrated spectrum shows strong absorption in the Lyman lines of atomic…

In a previous paper we reported on a discontinuity in the extreme horizontal branch (EHB) of the Galactic globular cluster NGC6752, which we called the second U-jump. This feature was attributed to a combination of post zero-age horizontal…

We present the results of spectroscopic analyses of hot horizontal branch (HB) stars in M 13 and M 3, which form a famous ``second parameter'' pair. From the spectra and Stroemgren photometry we derived -- for the first time in M 13 --…

We exploit multi-band Hubble Space Telescope photometry to investigate multiple populations (MPs) along the red horizontal branches (HBs) and red clumps of fourteen metal-rich Globular Clusters (GCs), including twelve Milky Way GCs and the…

The observed properties of galaxies are strongly dependent on both their total stellar mass and their morphology. Furthermore, the environment is known to play a strong role in shaping them. The galaxy population in the local universe that…

We examine the outer structure of 12 Galactic globular clusters using star-count analyses. Deep, two-color, photographic photometry is used to select and count stars with colors and magnitudes consistent with cluster-specific,…

We used FLAMES+GIRAFFE (Medusa mode) at the VLT to obtain moderately high resolution spectra for 30 red horizontal branch (RHB) stars, 4 RR Lyrae variables, and 17 blue horizontal branch (BHB) stars in the low-concentration, moderately…