Related papers: Structural parameters and blue stragglers in Sagit…

We computed proper motions of a selected sample of globular clusters projected on the central bulge, employing CCD images gathered along the last 25 years at the ESO-NTT, ESO-Danish and HST telescopes. We presented a method to derive their…

We present the latest results of our ongoing homogeneous cool C star survey of Local Group dwarf galaxies. We apply our two color photometric technique to the study of two small galaxies: the Sagittarius dwarf (SagDIG) and Leo I. We…

We present a deep color-magnitude diagram in the VI passbands of the globular cluster M54, a member of the Sagittarius dwarf galaxy. The data extend below the cluster's main sequence turn-off, allowing us to estimate the cluster's age. We…

We present a chemical and dynamical analysis of the leading arm (LA) and trailing arm (TA) of the Sagittarius (Sgr) stream, as well as for the Sgr dwarf galaxy core (SC), using red giant branch, main sequence, and RR Lyrae stars from large…

The formation of globular clusters remains an open debate. Dwarf starburst galaxies are efficient at forming young massive clusters with similar masses as globular clusters and may hold the key to understanding their formation. We study…

We present the stellar main sequence luminosity function (LF) of the disrupted, low-mass, low-concentration globular cluster Palomar 5 and its well-defined tidal tails, which emanate from the cluster as a result of its tidal interaction…

We present the metallicities and carbon abundances of four newly discovered metal-poor stars with $ -2.2 <$ [Fe/H] $< -1.6$ in the Sagittarius dwarf spheroidal galaxy. These stars were selected as metal-poor member candidates using a…

We present spectroscopic observations of a massive globular cluster in the dwarf irregular galaxy Sextans B, discovered by us on Hubble Space Telescope Wide Field and Planetary Camera 2 (HST WFPC2) images. Long-slit spectra were obtained…

This chapter explores how we might use the observed {\em statistics} of blue stragglers in globular clusters to shed light on their formation. This means we will touch on topics also discussed elsewhere in this book, such as the discovery…

We present time-series VI photometry of the metal-rich globular cluster NGC 6316. Our color-magnitude diagrams show a predominantly red-clump horizontal branch morphology with no evidence of the blue extensions seen in NGC 6388 and NGC…

We used a proper combination of high-resolution HST observations and wide-field ground based data to derive the radial star density profile of 26 Galactic globular clusters from resolved star counts (which can be all freely downloaded…

We report the first results of an ongoing spectroscopic survey of blue horizontal branch stars in the metal-rich ([Fe/H] ~ -0.5) globular clusters NGC 6388 and NGC 6441. Based on data obtained with the ESO-New Technology Telescope (NTT), we…

Blue straggler star (BSS) candidates have been observed in all old dwarf spheroidal galaxies (dSphs), however whether or not they are authentic BSSs or young stars has been a point of debate. To both address this issue and obtain a better…

We use two stellar populations in the globular cluster 47 Tucanae to trace its dynamical history: blue stragglers and low mass main sequence stars. We assumed that the blue stragglers were formed through stellar collisions in all regions of…

We have selelcted 556 Red Horizontal Branch (RHB) stars along the streams of the Sagittarius dwarf galaxy (Sgr) from SDSS DR7 spectroscopic data using a theoretical model. The metallicity and \alpha-elements distributions are investigated…

We present velocity dispersion measurements of 14 globular clusters in NGC 5128 (Centarus A) obtained with the MIKE echelle spectrograph on the 6.5m Magellan Clay telescope. These clusters are among the most luminous globular clusters in…

We present V, I photometry of the Sagittarius Dwarf Spheroidal galaxy (Sgr) for a region of ~ 1^{circ} times 1^{circ}, centered on the globular cluster M 54. This catalog is the largest database of stars (~500,000) ever obtained for this…

Spectroscopic observations of binary stars in globular clusters are essential to shed light on the poorly constrained period, eccentricity, and mass ratio distributions and to develop an understanding of the formation of peculiar stellar…

In open star clusters, where all members formed at about the same time, blue straggler stars are typically observed to be brighter and bluer than hydrogen-burning main-sequence stars, and therefore should already have evolved into giant…

We have used WFPC2 to construct B, V color-magnitude diagrams of four metal-rich globular clusters, NGC 104 (47 Tuc), NGC 5927, NGC 6388, and NGC 6441. All four clusters have well populated red horizontal branches (RHB), as expected for…