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Related papers: Galactic abundance gradients from Cepheids: alpha …

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We test the performance of our analysis technique for integrated-light spectra by applying it to seven well-studied Galactic GCs that span a wide range of metallicities. Integrated-light spectra were obtained by scanning the slit of the…

Solar and Stellar Astrophysics · Physics 2017-05-10 S. S. Larsen , J. P. Brodie , J. Strader

We present interstellar elemental abundance measurements derived from Space Telescope Imaging Spectrograph echelle observations of 47 sight lines extending up to 6.5 kpc through the Galactic disk. These paths probe a variety of interstellar…

Astrophysics · Physics 2009-11-13 Stefan I. B. Cartledge , J. T. Lauroesch , David M. Meyer , Ulysses J. Sofia

We obtained FLAMES-GIRAFFE spectra (R=22,500) at the ESO Very Large Telescope for 650 bulge red giant branch (RGB) stars and performed spectral synthesis to measure Mg, Ca, Ti, and Si abundances. This sample is composed of 474 giant stars…

Context. Open clusters provide valuable information on stellar nucleosynthesis and the chemical evolution of the Galactic disc, as their age and distances can be measured more precisely with photometry than for field stars. Aims. Our aim is…

This review recaps significant results as they apply to non-dwarf galaxies, including the Milky Way, spiral disks and bulges, and elliptical and lenticular galaxies. Conclusions that span the galaxy types treated here are as follows. All…

Astrophysics · Physics 2008-11-26 R. B. C. Henry , Guy Worthey

Individual chemical abundances for fourteen elements (C, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Ni) are derived for a sample of M-dwarfs using high-resolution near-infrared $H$-band spectra from the SDSS-IV/APOGEE survey. The…

Recent dynamical analysis based on Gaia data have revealed major accretion events in Milky Way's history. Nevertheless, our understanding of the primordial Galaxy is hindered because the bona fide identification of the most metal-poor and…

The rationale behind recent calibrations of the Cepheid PL relation using the Wesenheit formulation is reviewed and reanalyzed, and it is shown that recent conclusions regarding a possible change in slope of the PL relation for short-period…

Astrophysics of Galaxies · Physics 2014-11-20 David G. Turner

Sulphur is an important, volatile alpha element but its role in the Galactic chemical evolution is still uncertain. We derive the S abundances in RGB stars in three Galactic globular clusters (GC) that cover a wide metallicity range…

Astrophysics of Galaxies · Physics 2015-04-29 Nikolay Kacharov , Andreas Koch , Elisabetta Caffau , Luca Sbordone

We examine the \alpha-element abundance ratio, [\alpha/Fe], of 5620 stars, observed by the Sloan Extension for Galactic Understanding and Exploration survey in the region 6 kpc < R < 16 kpc, 0.15 kpc < |Z| < 1.5 kpc, as a function of…

In this paper we adopt a chemical evolution model, which is an improved version of the Chiappini, Matteucci and Gratton (1997) model, assuming two main accretion episodes for the formation of the Galaxy. The present model takes into account…

Astrophysics · Physics 2009-11-06 Cristina Chiappini , Francesca Matteucci , Donatella Romano

We present gas-phase abundances of carbon (C), $\alpha$-elements (O, Ne, Si, and Ar) and iron (Fe) obtained from stacked spectra of high-$z$ star-forming galaxies with the deep Near Infrared Spectrograph medium-resolution data from the…

We determine the radial abundance gradient of helium in the disc of the Galaxy from published spectra of 19 $\text{H}\thinspace \text{II}$ regions and ring nebulae surrounding massive O stars. We revise the Galactocentric distances of the…

Solar and Stellar Astrophysics · Physics 2020-06-16 J. E. Méndez-Delgado , C. Esteban , J. García-Rojas , K. Z. Arellano-Córdova , M. Valerdi

We present results of a survey of a 6-square-degree region near l=60, b=0 to search for distant Milky Way Cepheids. Few MW Cepheids are known at distances >~ R_0, limiting large-scale MW disk models derived from Cepheid kinematics; this…

Astrophysics · Physics 2009-10-30 Mark R. Metzger , Paul L. Schechter

We compare abundance ratio trends in a sample of $\sim 11,000$ Milky Way bulge stars ($R_{\rm GC} < 3$ kpc) from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) to those of APOGEE stars in the Galactic disk ($5$ kpc $<…

While looking for recently discovered distant Cepheids with an interesting chemical composition, we noticed one star (OGLE GD-CEP-1353) with extremely large equivalent widths of spectral lines of heavy elements. The aim of this work is to…

Solar and Stellar Astrophysics · Physics 2023-10-17 V. V. Kovtyukh , S. M. Andrievsky , K. Werner , S. A. Korotin

The connection between some features of the metallicity gradient in the Galactic disk, best revealed by Open Clusters and Cepheids, and the spiral structure, is explored. The step-like abrupt decrease in metallicity at 8.5 kpc (with R_0=…

Astrophysics of Galaxies · Physics 2015-05-28 J. R. D. Lepine , P. Cruz , S. Scarano , D. A. Barros , W. S. Dias , L. Pompeia , S. M. Andrievsky , G. Carraro , B. Famaey

Using G dwarfs from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey, we have determined a vertical metallicity gradient over a large volume of the Milky Way's disk, and examined how this gradient varies for…

Context. Open clusters are ideal test particles to study the chemical evolution of the Galactic disc. However the existing high-resolution abundance determinations, not only of [Fe/H], but also of other key elements, is largely insufficient…

Astrophysics of Galaxies · Physics 2015-05-28 R. Carrera , E. Pancino

The space velocities and Galactic orbital elements of stars calculated from the currently available high-accuracy observations in our summary catalog of spectroscopic magnesium abundances in dwarfs and subgiants in the solar neighborhood…

Astrophysics · Physics 2015-06-24 V. A. Marsakov , T. V. Borkova
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