Metal-rich globular clusters are important to study the chemical evolution of the Galaxy and one of the best approaches to better understand the physical processes occurring in stellar populations as building blocks of galaxies. We report on Mn, Cu, and Zn abundances of giant stars in metal-rich Galactic globular clusters (−0.70 < [Fe/H] < −0.11), measured on spectra obtained with the UVES spectrograph on the 8-m VLT UT2-Kueyen telescope.

Main results from a study of extremely metal-poor stars are briefly summarised.

Here, we present our on-going work on the determination of stellar parameters of giants in the Galactic Disks and Bulge observed with UVES on the VLT. We present some preliminarily results.

The VLT Survey Telescope (VST) is going to offer a unique chance to collect deep and wide field photometry in multi-directions, opening the door to a definitive mapping of the Galactic halo. In this shortcoming scenario, we present a pilot study aimed at recovering the halo stellar density using the Capodimonte Deep Field (OACDF, Alcalá et al. 2004). Turn-off stars are isolated and the relative color-magnitude diagram (CMD) is compared with synthetic CMDs. Our result is consistent with a power law exponent n≈ 3 over a range of Galactocentric distances from 8 to 40 kpc.

37 potential members of the red-giant branches of NGC 6192, NGC 6208 and NGC 6268 were observed in the UBV system, while 22 of them were also observed in the DDO system. The observations were made at La Silla and Cerro Tololo Inter-American observatories (Chile), using pulse-counting photoelectric photometers. Coravel radial velocities (RVs) were obtained at La Silla for 24 red giant candidates in the three clusters. Five stars of NGC 6192 have RVs in the narrow range -8.8 km/s < VR < -6.4 km/s, including two new spectroscopic binaries (SBs). Three stars of NGC 6208 – including a new SB – and three stars of NGC 6268 show similar RVs so that their physical membership to NGC 6208 and NGC 6268, respectively, is highly probable. Mean radial velocities are: -7.7 ± 0.38 km/s (NGC 6192), -32.21 ± 0.28 km/s (NGC 6208) and -15.11 ± 0.08 km/s (NGC 6268). We have also derived the following mean E(B-V) values from Janes (1977) iterative method: 0.63 ± 0.02 (NGC 6192), 0.31 ± 0.02 (NGC 6208) and 0.43 ± 0.02 (NGC 6268).

We present new near-infrared Ks photometry of the interesting Galactic globular cluster NGC 6441. The optical-NIR color-magnitude diagram shows evolutionary features that seem to agree with a canonical evolutionary framework. The K-band Period-Luminosity-Metallicity relation of RR Lyrae stars gives a distance estimate of 15.51±0.07 that is slightly larger previous estimates.

We have combined B, V, I time-series photometry from three different telescopes (SUBARU, TNG and HST) to study the variable star population of the remote Galactic globular cluster NGC 2419 and derive hints on a possible extragalactic origin for this cluster. We have discovered 40 new variables (34 RR Lyrae stars, 3 SX Phoenicis stars, Scuti 1 eclipsing binary system and 2 red irregular variables) doubling the number of known variable stars in NGC 2419.

We analyzed a sample of about 2500 stars extracted from the Sloan Digital Sky Survey with Teffin the range 4750÷6500 K and log g greater than 1.5. Atmospheric parameter estimates are obtained by comparing observed and synthetic spectral indices. The dependence of the α-enhancement phenomenon on stellar metallicity and on Galactic position is investigated.

We present TCS-CAIN, a NIR survey of the Galactic plane, recently made public at the Instituto de Astrofísica de Canarias, and some results derived from it: with star counts derived directly from it the structure of the inner the Milky Way can be dissected, and with low resolution spectra, (part of a follow-up program), its nature, specifically the metallicity distribution in the inner 4 kpc of the Galaxy, further understood.

Heliocentric (UVW) and galactocentric (VR VΦ VZ) space motions were derived for 38 RR Lyrae (RRL) and 79 blue horizontal branch (BHB) stars in a 200-sq degree area near the North Galactic Pole (NGP). A kinematic analysis of the 26 RRL and 52 BHB stars whose height (Z) above the plane is < 8 kpc shows that the sample is not homogeneous. Our BHB sample shows zero galactic rotation and roughly isotropic velocity dispersions. whereas the RRL sample shows a definite retrograde rotation and non-isotropic velocity dispersions. The combined BHB and RRL sample shows a smaller retrograde rotation that is similar to that found by Majewski et al. (1996) for a sample of subdwarfs in SA 57 at the NGP. There are significantly more RRL with negative W-velocity (streaming down) than positive W-velocity, whereas the numbers of BHB stars are comparable. This indicates the presence near the NGP of an accreted halo component that is rich in RRL (probably Oosterhoff type I) stars.

These results are presented in detail in a forthcoming paper (Kinman et al. 2007).

The publicly available stellar database from SDSS contains many hundreds of metal-poor stars with large enhancements of carbon. The Galactic extension of SDSS, SEGUE, will identify several thousand more. Many of these Carbon-Enhanced Metal-Poor (CEMP) stars are likely to be enhanced in s-process elements created by AGB companions and dumped to the surviving member of a binary pair through either Roche-Lobe mass transfer or the operation of a stellar wind (CEMP-s stars). Based on previous high-resolution investigation of CEMP stars, an interesting subset of this sample is expected to show little or no s-process enhancement (CEMP-no stars).

Utilizing a novel technique of automatically fitting [Fe/H] and [C/Fe] for a large number of stars from SDSS through spectral synthesis methods, we are able to derive a new estimate of the frequency of CEMP stars as a function of metallicity for the largest sample of stars to date. Using this approach, we can also measure abundances (or limits) for species such as Sr and Ba, which can be used to roughly separate CEMP stars into the CEMP-s and CEMP-no classes.

We present infrared observations with the integral field spectrometer SINFONI on the ESO-VLT (Very Large Telescope) Yepun of obscured stellar clusters in HII regions. The classification in spectral subclasses of the detected early type stars together with a determination of the interstellar extinction and the stellar apparent magnitudes enable us to obtain spectrophotometric distances, which are independent and complementary to kinematic distances and free from the ambiguity inherent to the determination of the latter. This study is part of a larger project, investigating the spatial distribution of Galactic Hii regions. Our primary aim is obtaining a more complete and less biased picture of the Milky Way's spiral structure.

The integrated light of open cluster remnants (OCRs) is expected to be similar to that of open clusters of comparable ages. Despite erosion of the mass function in remnants as a consequence of dynamical evolution, their integrated spectra could still be similar to those of the clusters of comparable age as long as a sufficient number of bright stars remain. In the present work we employ integrated spectroscopy and individual spectra of stars to analyze 8 OCRs and candidates which were previously classified as open clusters and a new unclassified object. The OCRs and possible open cluster remnants (POCRs) are underpopulated with respect to usual open clusters, but they show a significant density contrast of bright stars when compared to the Galactic field. The spectroscopic observations were carried out with the 2.15-m telescope at CASLEO (San Juan, Argentina) in the range 3800-6800 Å, during 2003 and 2004. We derive foreground interstellar reddening values and ages. We find in most of the sample that the derived properties are compatible with what should be expected for OCRs.

The globular cluster ω Cen is an outstanding object in terms of both its chemical and kinematic properties. Its large mass, spread in element abundances, chemical and kinematical segregations, as well as its peculiar orbit, all suggest that it is the surviving remnant of a larger system. In this contribution we deal with the chemical evolution of ω Cen in the framework of a model where it is the remnant of a dwarf spheroidal galaxy evolved in isolation and then swallowed and partially disrupted by the Milky Way. Both infall of primordial matter and metal-enriched gas outflows are necessary in order to reproduce the observed stellar metallicity distribution function, age-metallicity relation and several abundance ratios. Yet, as long as an ordinary stellar initial mass function and standard stellar yields are adopted, we fail by far to get the enormous helium enhancement required to explain the double main sequence of ω Cen.

We present our on-going work on the determination of elemental abundances of giants in the Galactic Bulge by means of infrared spectroscopy. We show a preliminarily reduced spectrum and a synthetic spectrum fit of the Bulge giant Arp 4203 recorded with the near-infrared, high-resolution Crires spectrograph mounted on the VLT during its science verification run in August 2006. Abundances derived from this spectrum are discussed.

On the basis of large photometric and spectroscopic datasets, we investigated the general properties of the different sub-populations of ω Centauri in different regions of the color-magnitude diagram. In particular, we analysed the morphology, the structure and the chemical properties of the stellar populations of the system in variuos evolutionary stages. Such a large observational effort allowed us to constraint the different hypotesis on the origin and chemical evolution of this peculiar stellar system.

IAC-pop is a code designed to solve the star formation history (SFH) of a complex stellar population system, like a galaxy, from the analysis of the color-magnitude diagram (CMD). It uses a genetic algorithm to minimize a χ2 merit function comparing the stellar distribution of an observed CMD and the stellar distributions of CMDs arising from linear combination of simple synthetic populations. To this purpose, IAC-star is used to compute a single seminal synthetic CMD from which the simple populations and their corresponding CMD stellar distributions are extracted.

In the current version, IAC-pop provides two different estimates of the errors in the SFH. It is offered for free use and can be downloaded from the site www.iac.es/iac-pop.html.

We present a new numerical model of star formation history and chemical evolution using the color-magnitude diagrams of resolved stars in galaxies. Our model differs from previous models in that it generates the simulated color-magnitude diagrams with the metal enrichment law calculated from the galactic chemical evolution model. We present a case of applying our model to a resolved galaxy in the Local Group: the Sextans dwarf spheroidal galaxy. It is found the the primary origin of the radial gradient of stellar population in this galaxy is star formation followed by metallicity.

This is a review of the progress of ESO/WFI Imaging and VLT/FLAMES spectroscopy of large numbers of individual stars in nearby dwarf spheroidal galaxies primarily by the Dwarf Abundances and Radial-velocities Team (DART). These observations have allowed us to show that neither the kinematics nor the abundance nor the spatial distributions are easy to explain in a straight forward manner for these smallest galaxies. The main result is that dwarf galaxies show complex and highly specific evolutionary and metal enrichment processes, especially at ancient times. This conclusively proves that these small galaxies are not the building blocks of the larger galaxies in the Local Group.

Recent (≤ 0.5 Gyr) star formation histories have a large impact on the observable properties of galaxies. Using HST/ACS observations, we have used the blue helium burning (BHeB) stars to construct spatially resolved star formation histories of M81 group dwarf galaxies with a time resolution of roughly 30 Myr over the last 500 Myr. We have designed a sample of ten galaxies spanning ranges of 6 magnitudes in luminosity, 1000 in current star formation rate, and 0.5 dex in metallicity. The ACS observations allow us to directly observe the strength and spatial relationships of all of the recent star formation in these galaxies. These observations are complemented by high-quality ancillary data (e.g., Spitzer, UV/optical/H-alpha/NIR, VLA HI). Our resolved star formation maps will be compared with star formation rates inferred from H-alpha, UV, and IR observations – allowing an independent calibration of these techniques. Given the ranges in metallicity, these observations will provide calibrations of stellar evolution tracks for young, low metallicity stars. These observations will also enable us to construct prescriptions of how star formation and feedback depend on metallicity, size, gas content, and current star formation rates in galaxies. Finally, I note that the new observations becoming available as a part of the ANGST (ACS Nearby Galaxies Survey Treasury Program) will allow a large number of dwarf galaxies to be analyzed in this way.