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Related papers: Str\"omgren metallicities for intermediate-age and…

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We performed a detailed analysis of the use of [C/N] measured in red giant branch stars between the completion of the first dredge up and the red giant branch bump ([C/N]_{FDU}) as age indicator. [C/N]_{FDU} cannot give accurate ages for…

Solar and Stellar Astrophysics · Physics 2015-11-11 Maurizio Salaris , Adriano Pietrinferni , Anna M. Piersimoni , Santi Cassisi

We use recently derived ages for 61 Milky Way (MW) globular clusters (GCs) to show that their age-metallicity relation (AMR) can be divided into two distinct, parallel sequences at [Fe/H] $\ga -1.8$. Approximately one-third of the clusters…

Astrophysics of Galaxies · Physics 2015-06-17 Ryan Leaman , Don A. VandenBerg , J. Trevor Mendel

Hubble Space Telescope (HST) fine guidance sensor observations were used to obtain parallaxes of eight metal-poor ([Fe/H] < -1.4) stars. The parallaxes of these stars determined by the revised Hipparcos reduction average 17% accuracy, in…

The mean metallicity of the Milky Way thin disc in the solar neighbourhood is still a matter of debate, and has recently been subject to upward revision (Haywood, 2001). Our star sample was drawn from a set of solar neighbourhood dwarfs…

Astrophysics · Physics 2009-11-07 M. Haywood

This is the second paper of a series devoted to study the stellar content of early-type galaxies. The goal of the series is to set constraints on the evolutionary status of these objects. We use a new set of models which include an improved…

Astrophysics · Physics 2009-11-11 P. Sanchez-Blazquez , J. Gorgas , N. Cardiel , J. J. Gonzalez

The estimate of stellar metallicities (Z*) of high-z galaxies are of paramount importance in order to understand the complexity of dust effects and the reciprocal interrelations among stellar mass, dust attenuation, stellar age, and…

An open issue about multiple stellar populations in globular clusters (GCs) is the possible existence of metallicity spreads in first generation (FG) stars. Recent estimates based on HST pseudo-colours map (PCM) derived unlikely large…

Astrophysics of Galaxies · Physics 2025-04-16 Eugenio Carretta , Angela Bragaglia

Wide-field JHKs near-infrared observations covering an area of 1.8x1.8 sq. deg. centred on M33 were obtained using WFCAM at UKIRT. These data show a large population of intermediate-age asymptotic giant branch stars (AGB). We have used both…

We report for the first time on the magnitude of the intrinsic [Fe/H] spread among ten old globular clusters (GCs) of the Large Magellanic Cloud (LMC). Such spreads are merely observed in approximately five per cent of the Milky Way GCs and…

Astrophysics of Galaxies · Physics 2018-10-31 Andrés E. Piatti , Andreas Koch

Context: The formation and evolution of disk galaxies are long standing questions in Astronomy. Understanding the properties of globular cluster systems can lead to important insights on the evolution of its host galaxy. Aims: We aim to…

Astrophysics of Galaxies · Physics 2015-06-12 Enio Cezario , Paula R. T. Coelho , Alan Alves-Brito , Duncan A. Forbes , Jean P. Brodie

We present a study of internal stellar population gradients in early-type cluster galaxies. Using the VLT VIMOS integral field unit, we observed 19 galaxies in the core of the Shapley Supercluster (z = 0.048). The radial trends in nine…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 T. D. Rawle , Russell J. Smith , J. R. Lucey

uvby(--$\beta$) photometry has been obtained for an additional 411 very metal-poor stars selected from the HK survey, and used to derive basic parameters such as interstellar reddenings, metallicities, photometric classifications,…

Astrophysics · Physics 2009-11-10 W. J. Schuster , T. C. Beers , R. Michel , P. E. Nissen , G. Garcia

Previously [Y/Mg] has been proven to be an age indicator for solar twins. Here, we investigate if this relation also holds for helium-core-burning stars of solar metallicity. High resolution and high signal-to-noise ratio (S/N)…

Solar and Stellar Astrophysics · Physics 2017-08-16 D. Slumstrup , F. Grundahl , K. Brogaard , A. O. Thygesen , P. E. Nissen , J. Jessen-Hansen , V. Van Eylen , M. G. Pedersen

We demonstrate how the metallicities of young super star clusters can be measured using novel spectroscopic techniques in the J-band. The near-infrared flux of super star clusters older than ~6 Myr is dominated by tens to hundreds of red…

In this work we study the stellar mass -- metallicity relation (MZR) of an extended sample of star-forming galaxies in the local Universe and its possible dependence with the star formation rate (SFR). A sample of $\sim$195000 Sloan Digital…

We present the first determination of the radial velocities and metallicities of 78 red giant stars in the isolated dwarf irregular galaxy WLM. Observations of the calcium II triplet in these stars were made with FORS2 at the VLT-UT2 in two…

In the study of galaxy integrated light, if photometric indicators could extract age and metallicity information of high enough quality, photometry might be vastly more efficient than spectroscopy for the same astrophysical goals. Toward…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Baitian Tang , Guy Worthey

We present an analysis of the stellar populations in a sample of ~7000 galaxies from the 6dF Galaxy Survey (6dFGS). We derive ages and metallicities using stellar population models. We also derive dynamical masses and dynamical…

Astrophysics · Physics 2009-11-13 Robert N. Proctor , Philip Lah , Duncan A. Forbes , Matthew Colless , Warrick Couch

This paper is a further step in the investigation of the morphology of the color-magnitude diagram of Galactic globular clusters, and the fine-tuning of theoretical models, made possible by the recent observational efforts to build…

We present a quantitative spectral analysis of five very massive stars in the Arches cluster, located near the Galactic center, to determine stellar parameters, stellar wind properties and, most importantly, metallicity content. The…

Astrophysics · Physics 2016-08-30 Francisco Najarro , Donald F. Figer , D. John Hillier , Rolf P. Kudritzki