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Related papers: Cepheids as tracers of the metallicity gradient ac…

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Here we discuss impacts of distance determinations on the Galactic disk traced by relatively young objects. The Galactic disk, about 40 kpc in diameter, is a cross-road of studies on the methods of measuring distances, interstellar…

Solar and Stellar Astrophysics · Physics 2018-05-16 Noriyuki Matsunaga , Giuseppe Bono , Xiaodian Chen , Richard de Grijs , Laura Inno , Shogo Nishiyama

We have derived the abundances of 36 chemical elements in one Cepheid star, ASAS 181024--2049.6, located R$_{\rm G}= 2.53$ kpc from the Galactic center. This star falls within a region of the inner thin disc poorly sampled in Cepheids. Our…

Astrophysics of Galaxies · Physics 2016-09-07 S. M. Andrievsky , R. P. Martin , V. V. Kovtyukh , S. A. Korotin , J. R. D. Lépine

During the last years and decades several individual studies and large-scale spectroscopic surveys significantly improved our knowledge of the Galactic metallicity distribution based on open clusters. The availability of Gaia data provided…

Astrophysics of Galaxies · Physics 2021-11-09 Martin Netopil , İnci Akkaya Oralhan , Hikmet Çakmak , Raúl Michel , Yüksel Karataş

We have used the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope to obtain V and I images of seven nearby galaxies. For each, we have measured a distance using the tip of the red giant branch (TRGB) method. By…

Astrophysics · Physics 2009-11-10 Shoko Sakai , Laura Ferrarese , Rob Kennicutt , Abi Saha

We derived the barium atmospheric abundances for a large sample of Cepheids, comprising 270 stars. The sample covers a large range of galactocentric distances, from about 4 to 15 kpc, so that it is appropriated to investigate the existence…

Astrophysics of Galaxies · Physics 2015-06-11 S. M. Andrievsky , J. R. D. Lepine , S. A. Korotin , R. E. Luck , V. V. Kovtyukh , W. J. Maciel

The observed radial and vertical metallicity distribution of old stars in the Milky Way disk provides a powerful constraint on the chemical enrichment and dynamical history of the disk. We present the radial metallicity gradient,…

We summarize a selection process to identify red giants in the direction of the southern warp of the Galactic disk, employing VI_C photometry and multi-object spectroscopy. We also present results from follow-up high-resolution, high-S/N…

Astrophysics · Physics 2008-11-26 Bruce W. Carney , David Yong , Luisa de Almeida , Patrick Seitzer

We point out that the absolute magnitude of the Galactic Cepheids, which have been used for local calibrations for Cepheid period-luminosity relation, shows an unexpectedly large metal abundance effect. This indicates that either Cepheids…

Astrophysics · Physics 2007-05-23 M. Sekiguchi , M. Fukugita

Spectra of HII regions obtained with Gemini/GMOS are used to derive the radial metallicity gradients of four small, low-mass spiral galaxies. The analysis of the outer disk of one of them, NGC 1058, uncovers the characteristic flattening…

Astrophysics of Galaxies · Physics 2019-07-24 Fabio Bresolin

We used the ugr magnitudes of 1,437,467 F-G type main-sequence stars with metal abundance -2<[Fe/H]<+0.2 dex and estimated radial and vertical metallicity gradients for high Galactic-latitude fields (b>50) of the Milky Way Galaxy. The…

Astrophysics of Galaxies · Physics 2019-01-16 S. Tuncel Guctekin , S. Bilir , S. Karaali , O. Plevne , S. Ak

We present Galactic mean metallicity maps derived from the first year of the SDSS-III APOGEE experiment. Mean abundances in different zones of Galactocentric radius (0 < R < 15 kpc) at a range of heights above the plane (0 < |z| < 3 kpc),…

We have obtained spectrophotometric observations of 41 anticenter planetary nebulae (PNe) located in the disk of the Milky Way. Electron temperatures and densities, as well as chemical abundances for He, N, O, Ne, S, Cl, and Ar were…

We present metallicities and their variations with different parameters for 36 high-latitude fields covering Galactic longitudes 0<l<360. The metallicities for relatively short vertical distances (z<2.5 kpc) show systematic fluctuations…

Astrophysics · Physics 2008-11-26 S. Ak , S. Bilir , S. Karaali , R. Buser , A. Cabrera-Lavers

The distribution of stellar abundances along the Galactic disk is an important constraint for models of chemical evolution and Galaxy formation. In this study we derive radial gradients of C, N, O, Mg, Al, Si, as well as S, from abundance…

Astrophysics · Physics 2009-11-10 Simone Daflon , Katia Cunha

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

We model the abundance gradients in the disk of the Milky Way for several chemical elements (O, Mg, Si, S, Ca, Sc, Ti, Co, V, Fe, Ni, Zn, Cu, Mn, Cr, Ba, La and Eu), and compare our results with the most recent and homogeneous observational…

Astrophysics · Physics 2009-11-11 G. Cescutti , F. Matteucci , P. Francois , C. Chiappini

Uncertainty in the metal abundance dependence of the Cepheid variable period- luminosity (PL) relation remains one of the outstanding sources of systematic error in the extragalactic distance scale and Hubble constant. To test for such a…

Up-to-date data on 2214 classical Cepheids have been used. The model of an exponential matter density distribution in the Galactic thin disk has been applied. New estimates of the radial disk scale length $h_R,$ the distance of the Sun from…

Astrophysics of Galaxies · Physics 2021-10-22 V. V. Bobylev , A. T. Bajkova

We present radial velocities and chemical abundances for nine stars in the old, distant open clusters Be 18, Be 21, Be 22, Be 32, and PWM 4. For Be 18 and PWM 4, these are the first chemical abundance measurements. Combining our data with…

Astrophysics of Galaxies · Physics 2015-06-05 David Yong , Bruce W. Carney , Eileen D. Friel

We examine the metallicity distribution of the Galactic thick disk using F, G, and K dwarf stars selected from the Sloan Digital Sky Survey, Data Release 8. Using the large sample of dwarf stars with proper motions and spectroscopically…

Astrophysics of Galaxies · Physics 2012-11-29 Kenneth Carrell , Yuqin Chen , Gang Zhao