Related papers: SALT and RR Lyrae variables: Our Galaxy, The Magel…
I will review the progress of VLT spectroscopy of large numbers of individual stars in nearby dwarf spheroidal galaxies. This spectroscopy has allowed us to obtain detailed insights into the chemical and dynamical properties of the resolved…
We use UCAC4 proper motions and WISE W1-band apparent magnitudes intensity-mean for almost 400 field RR Lyrae variables to determine the parameters of the velocity distribution of Galactic RR Lyrae population and constrain the zero points…
We present a search and analysis of variable stars in the recently discovered Crater~II dwarf galaxy. Based on $B$, $V$, $I$ data collected with the Isaac Newton Telescope (FoV$\sim$0.44 square degrees) we detected 37 variable stars, of…
Metallicities for six double mode RR Lyrae's (RRd's) in the Large Magellanic Cloud have been estimated using the DeltaS method. The derived [Fe/H] values are in the range [Fe/H] = -1.09 to -1.78 (or -0.95 to -1.58, adopting a different…
Here we review the efforts of a number of recent results that use old tracers to understand the build up of the Galaxy. Details that lead directly to using these old tracers to measure distances are discussed. We concentrate on the…
Galaxies in the Local Group span a factor of 15 in metallicity, ranging from the super-solar M31 to the Wolf-Lundmark-Melotte (WLM) galaxy, which is the lowest-metallicity (0.1xZsun) Local Group galaxy currently forming stars. Studies of…
Double-mode RR Lyrae variables (i.e. radial variables which are simultaneously pulsating in both fundamental and first overtone modes) appear a fundamental tool for investigating the mass of old Population II Horizontal Branch (HB) stars.…
The Ks-band magnitude distribution of carbon-rich and oxygen-rich asymptotic giant branch stars within Local Group galaxies like the Magellanic Clouds, NGC 6822, M33 and SagDIG is easily obtained from ground-based observations. Appropriate…
We present predicted relations connecting pulsational and evolutionary parameters, as based on a wide set of convective pulsating models of RR Lyrae stars with Z=0.001, Y=0.24 and mass and luminosity suitable for the ``old'' (age $>$ 8 Gyr)…
The characteristics and properties of the stellar populations and evolutionary histories of Local Group galaxies are summarized and compared to predictions of cosmological models. No clear signature of the re-ionization epoch is observed;…
Analytical models of chemical evolution, including inflow and outflow of gas, are important tools to study how the metal content in galaxies evolves as a function of time. In this work, we present new analytical solutions for the evolution…
We investigate the RR Lyrae population in NGC 147, a dwarf satellite galaxy of M31 (Andromeda). We used both Thuan-Gunn g-band ground-based photometry from the literature and Hubble Space Telescope Wide Field Planetary Camera 2 archival…
This review aims to give a summary of our understanding of galaxy evolution as infered from studies of nearby galaxies; how observations made with the Hubble Space Telescope have contributed significantly to our detailed understanding of…
We present theoretical predictions concerning horizontal branch stars in globular clusters, including RR Lyrae variables, as derived from synthetic procedures collating evolutionary and pulsational constraints. On this basis, we explore the…
Recent results on the evolution of Local Group dwarf galaxies obtained from VLT imaging and spectroscopy are briefly reviewed, and prospects for dwarf galaxy research at the VLT are discussed in the light of the current and forthcoming…
We present observations of RR Lyrae variables in the Local Group late-type spiral galaxy M33. Using the Advanced Camera for Surveys on the Hubble Space Telescope, we have identified 64 ab-type RR Lyraes in M33. We have estimated reddenings…
The star formation histories of Local Group galaxies are summarized. The three large spirals are discussed individually, whereas the discussion of the Local Group dwarfs concentrates on differences and commonalities. While Local Group…
Old open clusters are useful tools to study the Galactic disk properties, both present and past. Populous samples with properties determined both accurately and homogenously are necessary to draw reliable conclusions. We present here our…
Globular clusters are both primary fossils of galactic evolution and formation and are ideal laboratories for constraining the evolution of low-mass and metal-poor stars. RR Lyrae and type II Cepheid variables are low-mass, radially…
We used a combination of public RR Lyrae star catalogs and a Bayesian methodology to derive robust structural parameters of the inner Halo (<25 kpc) and Thick Disc of the Milky Way. RR Lyrae stars are an unequivocal tracer of old metal-poor…