Old Globular Clusters Masquerading as Young in NGC 4365?
High signal-to-noise ratio, low-resolution spectra have been obtained for 22 globular clusters (GCs) in NGC 4365. Some of these were selected as probable...
Old Main-Sequence Turnoff Photometry in the Small Magellanic Cloud. I. Constraints on the Star Formation History in Different Fields
We present ground-based B- and R-band color-magnitude diagrams (CMDs) reaching the oldest main-sequence (MS) turnoffs with good photometric accuracy for 12...
Old Main-Sequence Turnoff Photometry in the Small Magellanic Cloud. II. Star Formation History and its Spatial Gradients
We present a quantitative analysis of the star formation history (SFH) of 12 fields in the Small Magellanic Cloud (SMC) based on unprecedented deep [(B - R), R]...
Old stellar Galactic disc in near-plane regions according to 2MASS: Scales, cut-off, flare and warp
We have pursued two different methods to analyze the old stellar population near the Galactic plane, using data from the 2MASS survey. The first method is based...
Old-aged stellar distance indicators are present in all Galactic structures (halo, bulge, disk) and in galaxies of all Hubble types and, thus, are immensely...
OMEGA - OSIRIS Mapping of Emission-line Galaxies in A901/2 - I. Survey description, data analysis, and star formation and AGN activity in the highest density regions
We present an overview of and first results from the OMEGA (OSIRIS Mapping of Emission-line Galaxies in the multicluster system A901/2) survey. The ultimate...
On a New Method to Estimate the Distance, Reddening, and Metallicity of RR Lyrae Stars Using Optical/Near-infrared (B, V, I, J, H, K) Mean Magnitudes: ω Centauri as a First Test Case
We developed a new approach to provide accurate estimates of the metal content, reddening, and true distance modulus of RR Lyrae stars (RRLs). The method is...
On a New Near-Infrared Method to Estimate the Absolute Ages of Star Clusters: NGC 3201 as a First Test Case
We present a new method to estimate the absolute ages of stellar systems. This method is based on the difference in magnitude between the main-sequence turnoff...
On a New Parameter to Estimate the Helium Content in Old Stellar Systems
We introduce a new parameter Δξ-the difference in magnitude between the red giant branch (RGB) bump and the point on the main sequence (MS) at the same color as...