Related papers: Globular Clusters and Horizontal Branch

We present homogeneous scales of ages and metallicities for star clusters from very young objects, through intermediate-age ones up to the oldest known clusters. All the selected clusters have integrated spectra in the visible range, as…

We present deep (V ~ 28.0) BV photometry obtained with the wide field channel of the Advanced Camera for Surveys on board HST for four M31 globular clusters that were identified as candidate intermediate-age (age ~ 1-9 Gyr) by various…

Morphological aspects of the $V, \bv$ diagram of metal-rich globular clusters are analyzed, on the basis of stellar evolution models for horizontal-branch (HB) and red giant branch stars. These have been incorporated into detailed synthetic…

We have completely mapped the globular cluster NGC 1851 with VI CCD photometry, obtaining a CMD for ca. 20500 stars. From the apparent luminosity of the HB we derive a distance modulus (m-M)o=15.44+/-0.20. The presence of 7 "supra-HB" stars…

We present spectroscopic abundances and radial velocities for giant stars in the Galactic globular cluster omega Centauri based on the CaII infrared triplet. Two samples of stars were observed: 234 stars at M_V = 1.25 on the lower giant…

We investigate the globular cluster system around the low-luminosity S0 galaxy NGC 7457 with deep B, V, I photometry. From the V photometry the total number of globular clusters around the galaxy is estimated to be 178 +- 75. The specific…

We present a study of variable stars in globular cluster NGC 6401. The cluster is only $5.3\degr$ away from the Galactic centre and suffers from strong differential reddening. The photometric precision afforded us by difference image…

The optical colors of globular clusters (GCs) in most large early-type galaxies are bimodal. Blue and red GCs show a sharp difference in the radial profile of their surface number density in the sense that red GCs are more centrally…

Photometric metallicity formulae of fundamental-mode RR Lyr (RRab) stars are presented using globular-cluster data exclusively. The aim is to check whether this selection may help increasing the overall accuracy of the fits and eliminating…

A comparison is made between the age-metallicity relation obtained from four different types of studies: F and G stars in the Solar Neighbourhood, analysis of open clusters, galactic structure studies with the stellar population synthesis…

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,…

In the present work we analyzed seven globular clusters selected from their location in the Galactic bulge and with metallicity values in the range $-1.30\lesssim\rm{[Fe/H]}\lesssim-0.50$. The aim of this work is first to derive cluster…

Properties of 53 globular cluster systems are investigated. Strong correlations are found between parent galaxy luminosity and both the slope of the radial density profile for clusters and the width of the cluster color (metallicity)…

Star clusters are fundamental building blocks of galaxies. Their formation is related to the density and pressure in progenitor molecular clouds and their environmental conditions. To understand better the dynamical processes driving star…

X-ray observations of clusters at different redshifts are presented and compared. For the nearest cluster -- the Virgo cluster -- we show a comparison of the galaxy distribution and the distribution of the intra-cluster gas. Although the…

Our goal is to determine the stellar and wind properties of seven O stars in the cluster NGC2244 and three O stars in the OB association MonOB2. These properties give us insight into the mass loss rates of O stars, allow us to check the…

We make use of the Next Generation model atmospheres by Allard et al. (1997) and Hauschildt, Allard & Baron (1999) to compute theoretical models for low and very low-mass stars for selected metallicities in the range Z= 0.0002 to 0.002. On…

We report the distance and [Fe/H] value for the globular cluster NGC 5904 (M5) derived from the Fourier decomposition of the light curves of selected RRab and RRc stars. The aim in doing this was to bring these parameters into the…

When using Fe as a surrogate for ``metallicity'', the metallicity is best represented by the dominant species of Fe. Accordingly, we have derived a new globular cluster metallicity scale based on the equivalent widths of FeII lines measured…

A sample of 86 contact binary systems in 14 globular clusters with available color index data in (B-V) or in (V-I) has been analyzed. At least one third of all systems are numerous foreground Galactic Disk projections over long lines of…