English
Related papers

Related papers: Old open clusters in the outer Galactic disk

200 papers

We present metallicities, [Fe/H], and elemental abundance ratios, [X/Fe], for a sample of 24 Cepheids in the outer Galactic disk. The sample have Galactocentric distances covering 12 < R_GC (kpc) < 17.2 making them the most distant Galactic…

Astrophysics · Physics 2008-11-26 David Yong , Bruce W. Carney , Luisa de Almeida , Brian L. Pohl

Context. Recent evidences from spectroscopic surveys point towards the presence of a metal-poor, young stellar population in the chemical thin disk. In this context, the investigation of the spatial distribution and time evolution of…

Open clusters offer a unique possibility to study the time evolution of the radial metallicity gradients of several elements in our Galaxy, because they span large intervals in age and Galactocentric distance, and both quantities can be…

Astrophysics · Physics 2009-11-13 Laura Magrini , Paola Sestito , Sofia Randich , Daniele Galli

(Abridged) Recent spectroscopic surveys have begun to explore the Galactic disk system outside the solar neighborhood on the basis of large data samples. In this way, they provide valuable information for testing spatial and temporal…

The spatial distribution of elemental abundances in the disc of our Galaxy gives insights both on its assembly process and subsequent evolution, and on the stellar nucleogenesis of the different elements. Gradients can be traced using…

We present an analysis of the asymmetries in the population of Galactic M-giant stars present in the 2MASS All Sky catalogue. Several large-scale asymmetries are detected, the most significant of which is a strong elliptical-shaped stellar…

Astrophysics · Physics 2008-11-26 N. F. Martin , R. A. Ibata , M. Bellazzini , M. J. Irwin , G. F. Lewis , W. Dehnen

We analyze a sample of 3,944 low-resolution (R ~ 2000) optical spectra from the Sloan Digital Sky Survey (SDSS), focusing on stars with effective temperatures 5800 < Teff < 6300 K, and distances from the Milky Way plane in excess of 5 kpc,…

We present the results of an AAT wide-field camera survey of the stars in the Monoceros Ring and purported Canis Major overdensity in the Galactic longitudes of {\it l} = (193 - 276)$^\circ$. Current numerical simulations suggest that both…

The thick disk rotation--metallicity correlation, \partial V_\phi/\partial[Fe/H] =40\div 50 km s^{-1}dex^{-1} represents an important signature of the formation processes of the galactic disk. We use nondissipative numerical simulations to…

Globular clusters are some of the oldest bound stellar structures observed in the Universe. They are ubiquitous in large galaxies and are believed to trace intense star formation events and the hierarchical build-up of structure.…

This paper reports the star count predictions of warped and flaring models of the outer Milky Way disk. These have been suggested as possible locations of the lenses responsible for the microlensing events towards the Large Magellanic Cloud…

Astrophysics · Physics 2009-10-31 Geza Gyuk , Chris Flynn , N. Wyn Evans

We performed an uniform spectroscopic analysis of 1111 FGK dwarfs observed as part of the HARPS GTO planet search program. We applied a purely chemical approach, based on [alpha/Fe] ratio, to distinguish the various stellar components in…

Earth and Planetary Astrophysics · Physics 2013-07-09 V. Zh. Adibekyan , N. C. Santos , S. G. Sousa , G. Israelian , P. Figueira

Most of the metals (elements heavier than helium) ever produced by stars in the member galaxies of galaxy clusters currently reside within the hot, X-ray emitting intra-cluster gas. Observations of X-ray line emission from this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Norbert Werner , Ondrej Urban , Aurora Simionescu , Steven W. Allen

We present homogeneous and accurate iron abundances for almost four dozen (47) of Galactic Cepheids using high-spectral resolution (R$\sim$40,000) high signal-to-noise ratio (S/N $\ge$ 100) optical spectra collected with UVES at VLT. A…

Open clusters have long been used as tracers of Galactic structure. However, without a selection function to describe the completeness of the cluster census, it is difficult to quantitatively interpret their distribution. We create a method…

Open clusters are known as excellent tools for various topics in Galactic research. For example, they allow accurately tracing the chemical structure of the Galactic disc. However, the metallicity is known only for a rather low percentage…

Solar and Stellar Astrophysics · Physics 2016-01-13 M. Netopil , E. Paunzen , U. Heiter , C. Soubiran

Context: Chemical element abundances for distant Galactic globular clusters (GCs) hold important clues to the origin of the Milky Way halo and its substructures. Aims: We study the chemical composition of red giant stars in Pal 4 - one of…

Astrophysics of Galaxies · Physics 2015-05-18 Andreas Koch , Patrick Côté

We performed a uniform and detailed analysis of 1112 high-resolution spectra of FGK dwarfs obtained with the HARPS spectrograph at the ESO 3.6 m telescope (La Silla, Chile). Most stars have effective temperatures 4700 K < Teff < 6300 K and…

Astrophysics of Galaxies · Physics 2011-11-22 V. Zh. Adibekyan , N. C. Santos , S. G. Sousa , G. Israelian

The innermost regions of most galaxies are characterised by the presence of extremely dense nuclear star clusters. Nevertheless, these clusters are not the only stellar component present in galactic nuclei, where larger stellar structures…