Related papers: Multiple populations in Omega Centauri: a cluster …
We present elemental abundances for 855 red giant branch (RGB) stars in the globular cluster Omega Centauri (w Cen) from spectra obtained with the Blanco 4m telescope and Hydra multifiber spectrograph. The sample includes nearly all RGB…
We present wide-field and high-precision BV and Ca & Stromgren by photometry of omega Centauri and its RR Lyrae stars, which represents one of the most extensive photometric surveys to date for this cluster. The member stars of omega Cen…
Omega Centauri ($\omega$ Cen) is the most massive globular cluster of the Milky Way and has been the focus of many studies that reveal the complexity of its stellar populations and kinematics. However, most previous studies have used…
Some of the most massive globular clusters of our Milky Way, such as for example omega-Centauri, show a mixture of stellar populations spanning a few Gyr in age and 1.5 dex in metallicities. In contrast, standard formation scenarios predict…
$\omega$ Centauri, the most massive globular cluster in the Milky Way, has long been suspected to be the stripped nucleus of a dwarf galaxy that fell into the Galaxy a long time ago. There is considerable evidence for this scenario…
For the first time, the abundances of a large sample of subgiant and turn-off region stars in omega Centauri have been measured, the data base being medium resolution spectroscopy from FORS2 at the VLT. Absolute iron abundances were derived…
In this contribution, results from CCD vby Stroemgren photometry of a statistically complete sample of red giants and stars in the main sequence turn-off region in omega Centauri are presented. From the location of stars in the (b-y),m_1…
The globular cluster $\omega$ Centauri (NGC 5139) is a puzzling stellar system harboring several distinct stellar populations whose origin still represents a unique astrophysical challenge. Current scenarios range from primordial chemical…
Globular clusters (GCs) and many nuclear clusters (NCs) show evidence for hosting multiple generations of stellar populations. Younger stellar populations in NCs appear to reside in disk like structures, including the nuclear cluster in our…
Copper abundances are presented for 40 red-giant stars in Omega Cen as well as 15 red-giant members of the globular clusters NGC288, NGC362, NGC3201, NGC6752, and M4. A comparison with the halo field star pattern indicates that, unlike the…
We present multi-wavelength observations of the northern population of Omega Cen from the main-sequence turn-off to high on the red giant branch. We show that the best information about the metallicity and age of the stars can be gained…
We present [K/Fe] abundance ratios for a sample of 450 stars in Omega Centauri, using high resolution spectra acquired with the multi-object spectrograph FLAMES@VLT. Abundances for Fe, Na and Mg were also derived. We detected intrinsic K…
The star formation history of the globular cluster Omega Centauri is investigated in the context of an inhomogeneous chemical evolution model in which supernovae induce star formation. The proposed model explains recent observations for…
Chemical evolution models are presented for the anomalous globular cluster Omega Centauri. After demonstrating that the chemical features of Omega Cen can not be reproduced in the framework of the closed-box self-enrichment scenario, we…
The central regions of the globular cluster Omega Centauri ($\omega$ Cen) have been extensively studied, but its outer regions and tidal structure have been less so. Gaia's astrometry uncovered substantial tidal substructure associated with…
We present a detailed study of the radial distribution of the multiple populations identified in the Galactic globular cluster omega Cen. We used both space-based images (ACS/WFC and WFPC2) and ground-based images (FORS1@VLT and [email protected]…
We focus on two aspects of Omega Cen that are rather uncharacteristic of globular clusters: its metallicity distribution and its orbit. We use (1) a Washington (M-T_2,M)_o color-magnitude diagram containing 130,000 stars, (2) DDO51…
We present HST observations that show a bifurcation of colors in the middle main sequence of the globular cluster Omega Centauri. We see this in three different fields, observed with different cameras and filters. We also present high…
The discovery of the Sagittarius dwarf galaxy, which is being tidally disrupted by and merging with the Milky Way, supports the view that the halo of the Galaxy has been built up at least partially by the accretion of similar dwarf systems.…
We interpret the stellar population of $\omega$ Centauri by means of a population synthesis analysis, following the most recent observational guidelines for input metallicities, helium and [(C+N+O)/Fe] contents. We deal at the same time…