Related papers: Age and Metallicity Effects in Omega Centauri
We present a metallicity distribution based on photometry and spectra for 442 omega Cen cluster members that lie at the main sequence turnoff region of the color-magnitude diagram. This distribution is similar to that found for the red…
Omega Centauri is a peculiar Globular Cluster formed by a complex stellar population. To shed light on this, we studied 172 stars belonging to the 5 SGBs that we can identify in our photometry, in order to measure their [Fe/H] content as…
We present spectroscopic abundances and radial velocities for giant stars in the Galactic globular cluster omega Centauri based on the CaII infrared triplet. Two samples of stars were observed: 234 stars at M_V = 1.25 on the lower giant…
CCD vby Stroemgren photometry of a statistically complete sample of red giants and stars in the main sequence turn-off region in omega Centauri has been used to analyse the apparently complex star formation history of this cluster. From the…
We present wide-field and high-precision BV and Ca & Stromgren by photometry of omega Centauri, which represents one of the most extensive photometric surveys to date for this cluster. The member stars of omega Cen are well discriminated…
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 age estimates for over 8100 sub-giant branch (SGB) stars in Omega Centauri ($\omega$ Cen) to study its star formation history. Our large data set, which combines multi-wavelength HST photometry with MUSE metallicities, provides…
Omega Cen is composed of several stellar populations. Their history might allow us to reconstruct the evolution of this complex object. We performed a statistical cluster analysis on the large data set provided by Johnson and Pilachowski…
We present results of an extensive spectroscopic survey of Subgiant stars in the stellar system omega Centauri. Using infrared CaII triplet lines, we derived metallicities and radial velocities for more than 250 stars belonging to different…
The globular cluster Omega Centauri (NGC 5139) is the most massive and brightest cluster in our Galaxy. It has also a moderately high mass to light ratio (3.6) and an anomalous flattening (0.83) for a globular cluster. This cluster is also…
The most massive and complex globular clusters in the Galaxy are thought to have originated as the nuclear cores of now tidally disrupted dwarf galaxies, but the connection between globular clusters and dwarf galaxies is tenuous with the…
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…
We present metallicity measurements based on GIRAFFE@VLT spectra of 80 subgiant-branch stars of the Galactic globular cluster Omega Centauri. The VLT spectroscopic data are complemented by ACS/HST and [email protected] high-accuracy…
$\omega$ Cen is a rare example of a globular cluster where the iron abundance of the stars spans more than one order of magnitude. Many spectroscopic investigations of its red-giant- and sub-giant- branches have revealed multiple peaks in…
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…
We derive abundances of Fe, Na, O, and s-elements from GIRAFFE@VLT spectra for more than 200 red giant stars in the Milky Way satellite Omega Centauri. Our preliminary results are that: (i) we confirm that Omega Centauri exibiths large…
An understanding of the assembly history of the complex star cluster Omega Centauri has long been sought after, with many studies separating the stars on the color-magnitude diagram into multiple groupings across small magnitude ranges.…
Recent wide-field photometric surveys (Lee et al.; Pancino et al.) have shown the existence of a previously unknown metal-rich ([Fe/H] -0.6) stellar population in the galactic globular cluster omega Centauri. The discovery of this new…
Near-infrared spectra of 21 giants in omega Centauri, spanning the whole range of metallicities observed in this cluster, are presented. This work is part of a coordinated photometric and spectroscopic campaign in the optical and in the…
Globular cluster ages are more than just lower limits to the age of the universe; the distribution of ages constraints the timescales for galaxy formation and chemical evolution. Globular cluster populations with different metallicities…