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相关论文: Metallicity Distribution Functions, Radial Velocit…

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We present Fe, Si, and Ca abundances for 61 giants in Plaut's Window (l=-1,b=-8.5) and Fe abundances for an additional 31 giants in a second, nearby field (l=0,b=-8) derived from high resolution (R~25,000) spectra obtained with the Blanco…

太阳与恒星天体物理 · 物理学 2015-05-27 Christian I. Johnson , R. Michael Rich , Jon P. Fulbright , Elena Valenti , Andrew McWilliam

High resolution (R$\sim$22,500) spectra for 400 red clump giants, in four fields within $\rm -4.8^{\circ} \lesssim b \lesssim -3.4^{\circ}$ and $\rm -10^{\circ} \lesssim l \lesssim +10^{\circ}$, were obtained within the GIRAFFE Inner Bulge…

We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l,b)=(+5.25,-3.02) and (0,-12). The (+5.25,-3.02)…

太阳与恒星天体物理 · 物理学 2015-06-22 Christian I. Johnson , R. Michael Rich , Chiaki Kobayashi , Andrea Kunder , Andreas Koch

We present an abundance analysis based on high dispersion and high signal-to-noise ratio Keck spectra of a very highly microlensed Galactic bulge dwarf, OGLE-2007-BLG-349S, with Teff ~ 5400 K. The amplification at the time the spectra were…

天体物理学 · 物理学 2009-11-13 Judith G. Cohen , Wenjin Huang , A. Udalski , Andrew Gould , Jennifer Johnson

We present K-band spectra of more than 110 M giants in Galactic bulge fields interior to -4 degrees and as close as 0.2 degrees of the Galactic Center. From the equivalent widths of three features in these spectra, EW(Na),EW(Ca), and EW(CO)…

天体物理学 · 物理学 2009-10-31 Solange V. Ramirez , Andrew Stephens , Jay. A. Frogel , D. L. DePoy

In this paper, we present low resolution (R=500) near-infrared spectra for selected and serendipitous sources in six inner in-plane Galactic fields, with the aim of analysing the stellar content present. From the equivalent widths of the…

天体物理学 · 物理学 2009-11-13 C. González-Fernández , A. Cabrera-Lavers , P. L. Hammersley , F. Garzón

We determine the iron distribution function (IDF) for bulge field stars, in three different fields along the Galactic minor axis and at latitudes b=-4 deg, b=-6 deg, and b=-12 deg. A fourth field including NGC6553 is also included in the…

天体物理学 · 物理学 2011-05-18 M. Zoccali , V. Hill , A. Lecureur , B. Barbuy , A. Renzini , D. Minniti , A. Gomez , S. Ortolani

The presence of two stellar populations in the Milky Way bulge has been reported recently. We aim at studying the abundances and kinematics of stars in the outer bulge, thereby providing additional constraints on models of its formation.…

星系天体物理 · 物理学 2015-06-05 Stefan Uttenthaler , Mathias Schultheis , David. M. Nataf , Annie C. Robin , Thomas Lebzelter , B. Chen

We present abundances of several light, alpha, Fe-peak, and neutron-capture elements for 66 red giant branch (RGB) stars in the Galactic globular cluster Omega Centauri. Our observations lie in the range 12.0<V<13.5 and focus on the…

太阳与恒星天体物理 · 物理学 2011-02-11 Christian I. Johnson , Catherine A. Pilachowski , R. Michael Rich , Jon P. Fulbright

(Abridged) We analyzed the stellar parameters and radial velocities of ~1200 stars in five bulge fields as determined from the Gaia-ESO survey data (iDR1). We use VISTA Variables in The Via Lactea (VVV) photometry to obtain reddening values…

The O/H metallicity distribution of different samples of planetary nebulae in the bulge of the Milky Way and M31 are compared. O/H abundances are converted into [Fe/H] metallicity by the use of theoretical [O/Fe] x [Fe/H] relationships both…

天体物理学 · 物理学 2007-05-23 W. J. Maciel

Aims. The aim of this work is the study of abundances of the heavy elements Ba, La, Ce, Nd, and Eu in 56 bulge giants (red giant branch and red clump) with metallicities ranging from -1.3 dex to 0.5 dex. Methods. We obtained high-resolution…

星系天体物理 · 物理学 2016-01-20 M. Van der Swaelmen , B. Barbuy , V. Hill , M. Zoccali , D. Minniti , S. Ortolani , A. Gomez

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…

We present abundance analyses based on high dispersion and high signal-to-noise ratio Magellan spectra of two highly microlensed Galactic bulge stars in the region of the main sequence turnoff with Teff ~ 5650 K. We find that…

太阳与恒星天体物理 · 物理学 2009-06-25 Judith G. Cohen , Ian B. Thompson , Takahiro Sumi , Ian Bond , Andrew Gould , Jennifer A. Johnson , Wenjin Huang , Greg Burley

Several recent studies have demonstrated that the Galactic bulge hosts two components with different mean metallicities, and possibly different spatial distribution and kinematics. As a consequence, both the metallicity distribution and the…

We report new metallicity determinations for 39 red giants in a 220 square arcminute region, 1.8 degrees southwest of the bar of the Large Magellanic Cloud. These abundance measurements are based on spectroscopy of the Ca II infrared…

天体物理学 · 物理学 2009-10-31 A. A. Cole , T. A. Smecker-Hane , J. S. Gallagher

Constraints on the Galactic bulge/bar structure and formation history from stellar kinematics and metallicities mainly come from relatively high-latitude fields (|b|>4) where a complex mix of stellar population is seen. We aim here to…

We present the results of deep I and V-band photometry of the halo stars near the southeast minor axis of the Local Group spiral galaxy M33. An (I,V-I) color-magnitude diagram distinctly reveals the red giant branch stars at the bright end…

天体物理学 · 物理学 2009-11-10 R. Scott Brooks , Christine D. Wilson , William E. Harris

We present radial velocities, Fe, and Al abundances for 180 red giant branch (RGB) stars in the Galactic globular cluster Omega Centauri ($\omega$ Cen). The majority of our data lie in the range 11.0$<$V$<$13.5, which covers the RGB from…

天体物理学 · 物理学 2009-11-13 Christian I. Johnson , Catherine A. Pilachowski , Jennifer Simmerer , Dustin Schwenk

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…

天体物理学 · 物理学 2008-11-26 Bruce W. Carney , David Yong , Luisa de Almeida , Patrick Seitzer
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