Hayek, W., Wiesendahl, U., Christlieb, N., Eriksson, K., Korn, A. J., Barklem, P. S., ...
We report on a detailed abundance analysis of two strongly r-process enhanced, very metal-poor stars newly discovered in the HERES project, CS 29491-069 ([Fe/H]=-2.51, [r/Fe]=+1.1) and HE 1219-0312...
Automated Determination of [Fe/H] and [C/Fe] from Low-Resolution Spectroscopy (2009)
Marsteller, B., Beers, T. C., Sivarani, T., Rossi, S., Placco, V., Knapp, G. R., ...
We develop an automated spectral synthesis technique for the estimation of metallicities ([Fe/H]) and carbon abundances ([C/Fe]) for metal-poor stars, including carbon-enhanced metal-poor stars, for...
Halo streams in the 7th SDSS data release (2009)
Klement, R., Flynn, C., Fuchs, B., Beers, T. C., Prieto, C. Allende, ...
We have detected stellar halo streams in the solar neighborhood using data from the 7th public data release of the Sloan Digital Sky Survey (SDSS), which includes the directed stellar program SEGUE:...
Bonifacio, P., Spite, M., Cayrel, R., Hill, V., Spite, F., Francois, P., ...
CONTEXT:The detailed chemical abundances of extremely metal-poor (EMP) stars are key guides to understanding the early chemical evolution of the Galaxy. Most existing data are, however, for giant...
The kinematics of late type stars in the solar cylinder studied with SDSS data (2009)
Fuchs, B., Dettbarn, C., Beers, T. C., Bizyaev, D., Brewington, H., ...
We study the velocity distribution of Milky Way disk stars in a kiloparsec-sized region around the Sun, based on ~ 2 million M-type stars from DR7 of SDSS, which have newly re-calibrated absolute...
Lithium abundances of extremely metal-poor turnoff stars. (2009)
Aoki, W., Barklem, P.S., Beers, T.C., Christlieb, N., Inoue, S., Garcia Perez, A.E., ...
Original article can be found at: http://www.iop.org/EJ/journal/apj Copyright American Astronomical Society. DOI: 10.1088/0004-637X/698/2/1803 [Full text of this article is not available in the UHRA]
Toward constraints on galaxy formation scenarios: stellar properties from Galactic surveys (2008)
Fiorentin, P. Re, Beers, T. C., Zwitter, T., Lee, Y. S.
We present some of the strategies being developed to classify and parameterize objects obtained with spectra from the Sloan Digital Sky Survey (SDSS) and the RAdial Velocity Experiment (RAVE) and...
Schuler, S. C., Margheim, S. J., Sivarani, T., Asplund, M., Smith, V. V., Cunha, K., ...
We present the results from an analysis of the 8727ang forbidden [C I] line in high-resolution Gemini-S/bHROS spectra of three CEMP stars. We find the [C/Fe] ratios based on the [C I] abundances of...
Schoerck, T., Christlieb, N., Cohen, J. G., Beers, T. C., Shectman, S., Thompson, I., ...
We determine the metallicity distribution function (MDF) of the Galactic halo by means of a sample of 1638 metal-poor stars selected from the Hamburg/ESO objective-prism survey (HES). The sample was...
Fluorine in carbon-enhanced metal-poor stars: a binary scenario (2008)
Lugaro, M., De Mink, S. E., Izzard, R. G., Campbell, S. W., Karakas, A. I., Cristallo, S., ...
A super-solar fluorine abundance was observed in the carbon-enhanced metal-poor (CEMP) star HE 1305+0132 ([F/Fe] = +2.90, [Fe/H] = -2.5). We propose that this observation can be explained using a...
The stellar content of the Hamburg/ESO survey. IV. Selection of candidate metal-poor stars (2008)
Christlieb, N., Schoerck, T., Frebel, A., Beers, T. C., Wisotzki, L., Reimers, D.
We present the quantitative methods used for selecting candidate metal-poor stars in the Hamburg/ESO objective-prism survey (HES). The selection is based on the strength of the Ca II K line, B-V...
Zhao, G., Fiorentin, P. Re, Naab, T., Steinmetz, M., ...
We derive new constraints on the mass of the Milky Way's dark matter halo, based on a set of halo stars from SDSS as kinematic tracers. Our sample comprises 2401 rigorously selected Blue...
The ESO Large Programme First Stars (2008)
Bonifacio, P., Andersen, J., Andrievsky, S., Barbuy, B., Beers, T. C., Caffau, E., ...
In ESO period 65 (April-September 2000) the large programme 165.N-0276, led by Roger Cayrel, began making use of UVES at the Kueyen VLT telescope. Known within the Team and outside as ``First...
Roederer, I. U., Frebel, A., Shetrone, M. D., Prieto, C. A., Rhee, J., Gallino, R., ...
We present the first detailed abundance analysis of the metal-poor giant HKII 17435-00532. This star was observed as part of the University of Texas long-term project Chemical Abundances of Stars in...
Aoki, W., Beers, T.C., Sivarani, T., Marsteller, B., Lee, Y.S., Honda, S., ...
The original article can be found at: http://www.iop.org/EJ/journal/apj Copyright American Astronomical Society DOI: 10.1086/533517 [Full text of this article is not available in the UHRA]
Fluorine in carbon-enhanced metal-poor stars : a binary scenario (2008)
Lugaro, M.A., Mink, S.E. De, Izzard, R.G., Campbell, S.W., Karakas, A.I., Cristallo, S., ...
Aims. A super-solar fluorine abundance was observed in the carbon-enhanced metal-poor (CEMP) star HE 1305+0132 ([F/Fe] = +2.90, [Fe/H] = -2.5). We propose that this observation can be explained using...
A new sample of extremely/ultra metal-poor stars (2008)
Garcia Perez, A. E., Christlieb, N., Ryan, S. G., Beers, T. C., Aoki, W., Asplund, M., ...
Xue, X. X., Rix, H. W., Zhao, G., Re Fiorentin, P., Naab, T., Steinmetz, M., ...
We derive new constraints on the mass of the Milky Way's dark matter halo, based on 2401 rigorously selected blue horizontal-branch halo stars from SDSS DR6. This sample enables construction of the...
Hernández, J. I. González, Bonifacio, P., Caffau, E., Spite, M., Spite, F., ...
We have used high-resolution, high-S/N ratio spectra from the UVES spectrograph at the ESO VLT telescope. Long-term radial-velocity measurements and broad-band photometry allow us to determine...
On the newly discovered Canes Venatici II dSph galaxy (2007)
Greco, C., Dall'Ora, M., Clementini, G., Ripepi, V., Di Fabrizio, L., Kinemuchi, K., ...
We report on the detection of variable stars in the Canes Venatici II (CVn II) dwarf spheroidal galaxy, a new satellite of the Milky Way recently discovered by the Sloan Digital Sky Survey. We also...
Carnegie Observatories Astrophysics Series, Vol. 4: (2007)
Origin And Evolution, C. Allende Prieto, T. C. Beers, Y. Li, H. J. Newberg, R. Wilhelm, ...
The Sloan Digital Sky Survey (SDSS) is collecting photometry and intermediate resolution spectra for 10 stars in the thick-disk and stellar halo of the Milky Way. This massive dataset can be used to...
The SEGUE Stellar Parameter Pipeline. I. Description and Initial Validation Tests (2007)
Lee, Y. S., Beers, T. C., Sivarani, T., Prieto, C. Allende, Koesterke, L., Wilhelm, R., ...
We describe the development and implementation of the SEGUE (Sloan Extension for Galactic Exploration and Understanding) Stellar Parameter Pipeline (SSPP). The SSPP derives, using multiple...
The SEGUE Stellar Parameter Pipeline. II. Validation with Galactic Globular and Open Clusters (2007)
Lee, Y. S., Beers, T. C., Sivarani, T., Johnson, J. A., An, D., Wilhelm, R., ...
We validate the performance and accuracy of the current SEGUE (Sloan Extension for Galactic Understanding and Exploration) Stellar Parameter Pipeline (SSPP), which determines stellar atmospheric...
Prieto, C. Allende, Sivarani, T., Beers, T. C., Lee, Y. S., Koesterke, L., Shetrone, M., ...
We report high-resolution spectroscopy of 125 field stars previously observed as part of the Sloan Digital Sky Survey and its program for Galactic studies, the Sloan Extension for Galactic...
Distances to Galactic high-velocity clouds. Complex C (2007)
Wakker, B. P., York, D. G., Howk, J. C., Barentine, J. C., Wilhelm, R., Peletier, R. F., ...
We report the first determination of a distance bracket for the high-velocity cloud (HVC) complex C. Combined with previous measurements showing that this cloud has a metallicity of 0.15 times solar,...
First Stars VIII -- Enrichment of the neutron-capture elements in the early Galaxy (2007)
Francois, P., Depagne, E., Hill, V., Spite, M., Spite, F., Plez, B., ...
Our aim is to measure accurate, homogeneous neutron-capture element abundances for the sample of 32 EMP giant stars studied earlier in this series, including 22 stars with [Fe/H] $< -$3.0. Based on...
Distances to Galactic high-velocity clouds. I. Cohen Stream, complex GCP, cloud g1 (2007)
Wakker, B. P., York, D. G., Wilhelm, R., Barentine, J. C., Richter, P., Beers, T. C., ...
The high- and intermediate-velocity interstellar clouds (HVCs/IVCs) are tracers of energetic processes in and around the Milky Way. Clouds with near-solar metallicity about one kpc above the disk...
Nucleosynthesis in the Early Galaxy (2007)
Montes, F., Beers, T. C., Cowan, J., Elliot, T., Farouqi, K., Gallino, R., ...
Recent observations of r-process-enriched metal-poor star abundances reveal a non-uniform abundance pattern for elements $Z\leq47$. Based on non-correlation trends between elemental abundances as a...
Fluorine in a Carbon-Enhanced Metal-Poor Star (2007)
Schuler, S. C., Cunha, K., Smith, V. V., Sivarani, T., Beers, T. C., Lee, Y. S.
The fluorine abundance of the Carbon-Enhanced Metal-Poor (CEMP) star HE 1305+0132 has been derived by analysis of the molecular HF (1-0) R9 line at 2.3357 microns in a high-resolution (R = 50,000)...
Two Stellar Components in the Halo of the Milky Way (2007)
Carollo, D., Beers, T. C., Lee, Y. S., Chiba, M., Norris, J. E., Wilhelm, R., ...
The halo of the Milky Way provides unique elemental abundance and kinematic information on the first objects to form in the Universe, which can be used to tightly constrain models of galaxy formation...
Estimation of stellar atmospheric parameters from SDSS/SEGUE spectra (2007)
Fiorentin, P. Re, Lee, Y. S., Beers, T. C., Sivarani, T., Wilhelm, R., ...
We present techniques for the estimation of stellar atmospheric parameters (Teff,logg,[Fe/H]) for stars from the SDSS/SEGUE survey. The atmospheric parameters are derived from the observed...
The Hercules-Aquila Cloud (2007)
Belokurov, V., Evans, N. W., Bell, E. F., Irwin, M. J., Hewett, P. C., Koposov, S., ...
We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The Cloud is centered at a Galactic longitude of about 40 degrees and extends...
Discovery of an Unusual Dwarf Galaxy in the Outskirts of the Milky Way (2007)
Irwin, M. J., Belokurov, V., Evans, N. W., Ryan-Weber, E. V., Koposov, S., ...
In this Letter, we announce the discovery of a new dwarf galaxy, Leo T, in the Local Group. It was found as a stellar overdensity in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The...
Estimation of stellar atmospheric parameters from SDSS/SEGUE spectra (2007)
Re Fiorentin, P., Lee, Y. S., Beers, T. C., Sivarani, T., Wilhelm, R., ...
We present techniques for the estimation of stellar atmospheric parameters (T_eff, log~g, [Fe/H]) for stars from the SDSS/SEGUE survey. The atmospheric parameters are derived from the observed...
Discovery of an unusual dwarf galaxy in the outskirts of the Milky Way (2007)
Irwin, M. J., Belokurov, V., Evans, N. W., Ryan-Weber, E. V., Koposov, S., ...
We announce the discovery of a new dwarf galaxy, Leo T, in the Local Group. It was found as a stellar overdensity in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude...
Cats and dogs, hair and a hero: a quintet of New Milky Way companions (2007)
Belokurov, V., Zucker, D. B., Evans, N. W., Kleyna, J. T., Koposov, S., Hodgkin, S. T., ...
We present five new satellites of the Milky Way discovered in Sloan Digital Sky Survey (SDSS) imaging data, four of which were followed up with either the Subaru or the Isaac Newton Telescopes. They...
An Orphan in the ``Field of Streams'' (2007)
Belokurov, V., Evans, N. W., Irwin, M. J., Lynden-Bell, D., Yanny, B., Vidrih, S., ...
We use Sloan Digital Sky Survey Data Release 5 photometry and spectroscopy to study a tidal stream that extends over ~50° in the north Galactic cap. From the analysis of the path of the stream and...
The Hercules-Aquila cloud (2007)
Belokurov, V., Evans, N. W., Bell, E. F., Irwin, M. J., Hewett, P. C., Koposov, S., ...
We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The cloud is centered at a Galactic longitude of l~40deg and extends above...
Nucleosynthesis in the early galaxy (2007)
Montes, F., Beers, T. C., Cowan, J., Elliot, T., Farouqi, K., Gallino, R., ...
Carbon enhanced metal-poor stars I. Chemical compositions of 26 stars. (2007)
Aoki, W., Beers, T.C., Christlieb, N., Norris, J.E., Ryan, S.G., Tsangarides, S.
Original article can be found at: http://www.iop.org/EJ/journal/apj Copyright American Astronomical Society. DOI: 10.1086/509817 [Full text of this article is not available in the UHRA]
Aoki, W., Honda, S., Beers, T.C., Takada-Hidai, M., Iwamoto, N., Tominaga, N., ...
Original article can be found at: http://www.iop.org/EJ/journal/apj Copyright American Astronomical Society. DOI: 10.1086/512601 [Full text of this article is not available in the UHRA]
Discovery of an unusual dwarf galaxy in the outskirts of the Milky Way (2007)
Irwin, M. J., Belokurov, V., Evans, N. W., Ryan-Weber, E. V., Koposov, S., ...
We announce the discovery of a new dwarf galaxy, Leo T, in the Local Group. It was found as a stellar overdensity in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude...
Discovery of an unusual dwarf galaxy in the outskirts of the Milky Way (2007)
Irwin, M. J., Belokurov, V., Evans, N. W., Ryan-Weber, E. V., Koposov, S., ...
We announce the discovery of a new dwarf galaxy, Leo T, in the Local Group. It was found as a stellar overdensity in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude...
First stars VII. Lithium in extremely metal poor dwarfs (2006)
Bonifacio, P., Molaro, P., Sivarani, T., Cayrel, R., Spite, M., Spite, F., ...
Aims. This study aims to determine the level and constancy of the Spite plateau as definitively as possible from homogeneous high-quality VLT-UVES spectra of 19 of the most metal-poor dwarf stars...
Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions (2006)
Belokurov, V., Zucker, D. B., Evans, N. W., Kleyna, J. T., Koposov, S., Hodgkin, S. T., ...
We present five new satellites of the Milky Way discovered in Sloan Digital Sky Survey (SDSS) imaging data, four of which were followed-up with either the Subaru or the Isaac Newton Telescopes. They...
Frebel, A., Christlieb, N., Norris, J. E., Beers, T. C., Bessell, M. S., Rhee, J., ...
We present a sample of 1777 bright (9
A Curious New Milky Way Satellite in Ursa Major (2006)
Zucker, D. B., Belokurov, V., Evans, N. W., Kleyna, J. T., Irwin, M. J., Wilkinson, M. I., ...
In this Letter, we study a localized stellar overdensity in the constellation of Ursa Major, first identified in Sloan Digital Sky Survey (SDSS) data and subsequently followed up with Subaru imaging....
An Orphan in the "Field of Streams" (2006)
Belokurov, V., Evans, N. W., Irwin, M. J., Lynden-Bell, D., Yanny, B., Vidrih, S., ...
We use Sloan Digital Sky Survey Data Release 5 photometry and spectroscopy to study a tidal stream that extends over 50 degrees in the North Galactic Cap. From the analysis of the path of the stream...
CS 30322-023: an ultra metal-poor TP-AGB star? (2006)
Masseron, T., Van Eck, S., Famaey, B., Goriely, S., Plez, B., Siess, L., ...
With [Fe/H] = -3.5, CS 30322-023 is the most metal-poor star to exhibit a clear s-process signature and the most metal-poor ``lead star'' known. CS 30322-023 is also remarkable in having the lowest...
Spite, M., Cayrel, R., Hill, V., Spite, F., Francois, P., Plez, B., ...
Extremely metal-poor (EMP) stars preserve a fossil record of the composition of the ISM when the Galaxy formed. It is crucial, however, to verify whether internal mixing has modified their surface....
The Field of Streams: Sagittarius and its Siblings (2006)
Belokurov, V., Zucker, D. B., Evans, N. W., Gilmore, G., Vidrih, S., Bramich, D. M., ...
We use Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) u,g,r,i,z photometry to study Milky Way halo substructure in the area around the North Galactic Cap. A simple color cut (g-r < 0.4) reveals...
The Origin of the Bifurcation in the Sagittarius Stream (2006)
Fellhauer, M., Belokurov, V., Evans, N. W., Wilkinson, M. I., Zucker, D. B., Gilmore, G., ...
The latest Sloan Digital Sky Survey data reveal a prominent bifurcation in the distribution of debris of the Sagittarius dwarf spheroidal (Sgr) beginning at a right ascension of roughly 190 degrees....
A New Milky Way Dwarf Satellite in Canes Venatici (2006)
Zucker, D. B., Belokurov, V., Evans, N. W., Wilkinson, M. I., Irwin, M. J., Sivarani, T., ...
In this Letter, we announce the discovery of a new dwarf satellite of the Milky Way, located in the constellation Canes Venatici. It was found as a stellar overdensity in the North Galactic Cap using...
A Faint New Milky Way Satellite in Bootes (2006)
Belokurov, V., Zucker, D. B., Evans, N. W., Wilkinson, M. I., Irwin, M. J., Hodgkin, S., ...
In this Letter, we announce the discovery of a new satellite of the Milky Way in the constellation of Bootes at a distance of 60 kpc. It was found in a systematic search for stellar overdensities in...
Strömgren Photometry and High Resolution Spectroscopy of Very Metal-Poor Stars (2006)
R. Michel, T. C. Beers, W. J. Schuster
Strömgren Photometry and High Resolution Spectroscopy of Very Metal-Poor Stars
Early Star Formation, Nucleosynthesis, and Chemical Evolution in Proto-Galactic Clouds (2006)
Saleh, L., Beers, T. C., Mathews, G. J.
We present numerical simulations to describe the nucleosynthesis and evolution of pre-Galactic clouds in a model which is motivated by cold dark matter simulations of hierarchical galaxy formation....
Piau, L., Beers, T. C., Balsara, D. S., Sivarani, T., Truran, J. W., Ferguson, J. W.
Since the pioneering observations of Spite & Spite in 1982, the constant lithium abundance of metal-poor ([Fe/H]
Jonsell, K., Barklem, P. S., Gustafsson, B., Christlieb, N., Hill, V., Beers, T. C., ...
We have derived abundances of 33 elements and upper limits for 6 additional elements for the metal-poor ([Fe/H] = -2.42) turn-off star HE 0338-3945 from high-quality VLT-UVES spectra. The star is...
The Galactic Nature of High Velocity Cloud Complex WB (2006)
Thom, C., Putman, M. E., Gibson, B. K., Christlieb, N., Flynn, C., Beers, T. C., ...
We have detected absorption lines from the High Velocity Cloud Complex WB in the spectrum of the star HE1048+0231. This detection sets an upper distance limit to the cloud of 8.8^{+2.3}_{-1.3} kpc....
A new Milky Way dwarf satellite in Canes Venatici (2006)
Zucker, D. B., Belokurov, V., Evans, N. W., Wilkinson, M. I., Irwin, M. J., Sivarani, T., ...
In this Letter, we announce the discovery of a new dwarf satellite of the Milky Way, located in the constellation Canes Venatici. It was found as a stellar overdensity in the north Galactic cap using...
A curious Milky Way satellite in Ursa Major (2006)
Zucker, D. B., Belokurov, V., Evans, N. W., Kleyna, J. T., Irwin, M. J., Wilkinson, M. I., ...
In this Letter, we study a localized stellar overdensity in the constellation of Ursa Major, first identified in Sloan Digital Sky Survey (SDSS) data and subsequently followed up with Subaru imaging....
A faint new Milky Way satellite in Bootes (2006)
Belokurov, V., Zucker, D. B., Evans, N. W., Wilkinson, M. I., Irwin, M. J., Hodgkin, S., ...
We announce the discovery of a new satellite of the Milky Way in the constellation of Bootes at a distance of ~60 kpc. It was found in a systematic search for stellar overdensities in the north...
The field of streams: Sagittarius and its siblings (2006)
Belokurov, V., Zucker, D. B., Evans, N. W., Gilmore, G., Vidrih, S., Bramich, D. M., ...
We use Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) u, g, r, i, z photometry to study Milky Way halo substructure in the area around the north Galactic cap. A simple color cut (g-r
A high-resolution spectral analysis of three carbon-enhanced metal-poor stars (2006)
Goswami, A, Aoki, W, Beers, T. C, Christlieb, N, Norris, J. E, Ryan, S. G, ...
We present results of an analysis of high-resolution spectra obtained with the Subaru Telescope High Dispersion Spectrograph, of two Carbon-Enhanced Metal-Poor stars, HE 1305+0007 and HE 1152-0355,...
A high-resolution spectral analysis of three carbon-enhanced metal-poor stars. (2006)
Goswami, A., Aoki, W., Beers, T.C., Christlieb, N., Norris, J.E., Ryan, S.G., ...
The SDSS-I Value-Added Catalog of stellar parameters and the SEGUE pipeline (2006)
Beers, T. C., Lee, Y., Sivarani, T., Allende Prieto, C., Wilhelm, R., Fiorentin, P. Re, ...
We report on the development, calibration, and refinement of the SDSS-I Value Added Catalog (VAC) of stellar abundances, temperatures, and surface gravities. This catalog is based on observations of...
Aoki, W., Bisterzo, S., Gallino, R., Beers, T.C., Norris, J.E., Ryan, S.G., ...
Astrophysical Journal, 650(2006) S.L127-L130
Prieto, C. Allende, Beers, T. C., Wilhelm, R., Newberg, H. J., Rockosi, C. M., Yanny, B., ...
(Abridged) We perform an analysis of spectra and photometry for 22,770 stars included in the third data release (DR3) of the SDSS. We measure radial velocities and, based on a model-atmosphere...
Wanajo, S., Nomoto, K., Iwamoto, N., Ishimaru, Y., Beers, T. C.
Recent spectroscopic studies have revealed the presence of numerous carbon-enhanced, metal-poor stars with [Fe/H] < -2.0 that exhibit strong enhancements of s-process elements. These stars are...
Frebel, A., Aoki, W., Christlieb, N., Ando, H., Asplund, M., Barklem, P. S., ...
We describe the discovery of HE 1327-2326, a dwarf or subgiant with [Fe/H]}=-5.4. The star was found in a sample of bright metal-poor stars selected from the Hamburg/ESO survey. Its abundance pattern...
HE1327-2326, an unevolved star with [Fe/H] (2005)
Aoki, W., Frebel, A., Christlieb, N., Norris, J. E., Beers, T. C., Minezaki, T., ...
We present the elemental abundances of HE1327-2326, the most iron-deficient star known, determined from a comprehensive analysis of spectra obtained with the Subaru Telescope High Dispersion...
The Origins of Two Classes of Carbon-Enhanced, Metal-Poor Stars (2005)
Ryan, S. G., Aoki, W., Norris, J. E., Beers, T. C.
We have compiled composition, luminosity, and binarity information for carbon-enhanced, metal-poor (CEMP) stars reported by recent studies. We divided the CEMP star sample into two classes, having...
Barklem, P. S., Christlieb, N., Beers, T. C., Hill, V., Bessell, M. S., Holmberg, J., ...
We present the results of analysis of ``snapshot'' spectra of 253 metal-poor halo stars -3.8 < [Fe/H] < -1.5 obtained in the HERES survey. The spectra are analysed using an automated line profile...
Nucleosynthetic signatures of the first stars (2005)
Frebel, A., Aoki, W., Christlieb, N., Ando, H., Asplund, M., Barklem, P.S., ...
Mg abundances in metal-poor halo stars as a tracer of early Galactic mixing (2005)
Arnone, E., Ryan, S.G., Argast, D., Norris, J.E., Beers, T.C.
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
The Binary Frequency Among Carbon-enhanced, s-Process-rich, Metal-poor Stars (2005)
Lucatello, S., Tsangarides, S., Beers, T.C., Carretta, E., Gratton, R.G., Ryan, S.G.
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Christleib, N., Beers, T.C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
On the Binarity of Carbon-Enhanced, Metal-Poor Stars (2004)
Tsangarides, S., Ryan, S. G., Beers, T. C.
We report on a programme to monitor the radial velocities of a sample of candidate and confirmed carbon-enhanced, metal-poor (CEMP) stars. We observed 45 targets using the Echelle Spectrographs of...
Christlieb, N., Beers, T. C., Thom, C., Wilhelm, R., Rossi, S., Flynn, C., ...
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars...
Lead abundance in the uranium star CS 31082-001 (2004)
Plez, B., Hill, V., Cayrel, R., Spite, M., Barbuy, B., Beers, T. C., ...
In a previous paper we were able to measure the abundance of uranium and thorium in the very-metal poor halo giant BPS CS 31082-001, but only obtained an upper limit for the abundance of lead (Pb)....
Mg abundances in metal-poor halo stars as a tracer of early Galactic mixing (2004)
Arnone, E., Ryan, S. G., Argast, D., Norris, J. E., Beers, T. C.
We present results of a detailed chemical analysis performed on 23 main-sequence turnoff stars having -3.4
Christlieb, N., Beers, T. C., Barklem, P. S., Bessell, M., Hill, V., Holmberg, J., ...
We report on a dedicated effort to identify and study metal-poor stars strongly enhanced in r-process elements ([r/Fe] > 1 dex; hereafter r-II stars), the Hamburg/ESO R-process Enhanced Star survey...
Carbon-Enhanced Metal-Poor Stars in the Early Galaxy (2004)
Marsteller, B., Beers, T. C., Rossi, S., Christlieb, N., Bessell, M., Rhee, J.
Very metal-deficient stars that exhibit enhancements of their carbon abundances are of crucial importance for understanding a number of issues -- the nature of stellar evolution among the first...
Efficient Searches for r-Process-Enhanced, Metal-Poor Stars (2004)
Beers, T. C., Barklem, P. S., Christlieb, N., Hill, V.
Neutron-capture-enhanced, metal-poor stars are of central importance to developing an understanding of the operation of the r-process in the early Galaxy, thought to be responsible for the formation...
Oxygen Overabundance in the Extremely Iron-poor Star CS 29498-043 (2004)
Aoki, W., Norris, J.E., Ryan, S.G., Beers, T.C., Christlieb, N., Tsangarides, S., ...
Honda, S., Aoki, W., Ando, H., Izumiura, H., Kajino, T., Kambe, E., ...
Schuster, W. J., Beers, T. C., Michel, R., Nissen, P. E., Garcia, G.
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,...
Spectroscopic Studies of Extremely Metal-Poor Stars with Subaru/HDS:I. Observational Data (2004)
Honda, S., Aoki, W., Ando, H., Izumiura, H., Kajino, T., Kambe, E., ...
We have obtained high-resolution (R $\simeq$ 50,000 or 90,000), high-quality (S/N $\ga$ 100) spectra of 22 very metal-poor stars ([Fe/H] $\la$ -2.5) with the High Dispersion Spectrograph fabricated...
Honda, S., Aoki, W., Kajino, T., Ando, H., Beers, T. C., Izumiura, H., ...
We present the abundance analyses for the neutron-capture elements, and discuss the observed abundance distributions in very metal-poor stars with excesses of r-process elements. As has been found by...
Lead abundance in the uranium star CS 31082-001 (2004)
Plez, B., Hill, V., Cayrel, R., Spite, M., Barbuy, B., Beers, T. C., ...
In a previous paper we were able to measure the abundance of uranium andthorium in the very-metal poor halo giant BPS CS31082-001, but only obtained an upper limit for the abundanceof lead (Pb). We...
Christlieb, N., Beers, T. C., Barklem, P. S., Bessell, M., Hill, V., Holmberg, J., ...
We report on a dedicated effort to identify and study metal-poor stars strongly enhanced in r-process elements ([r/Fe]>1 dex; hereafter r-IIstars), the Hamburg/ESO R-process Enhanced Star survey...
First stars IV. CS 29497-030: Evidence for operation of the s-process at very low metallicity (2004)
Sivarani, T., Bonifacio, P., Molaro, P., Cayrel, R., Spite, M., Spite, F., ...
We present an abundance analysis of the very metal-poor, carbon-enhancedstar CS 29497-030. Our results indicate that this unusually hot turnoffstar (Teff = 6650 K, log g = 3.5) has a metallicity...
HE0107-5240, A Chemically Ancient Star.I. A Detailed Abundance Analysis (2003)
Christlieb, N., Gustafsson, B., Korn, A. J., Barklem, P. S., Beers, T. C., Bessell, M. S., ...
We report a detailed abundance analysis for HE0107-5240, a halo giant with [Fe/H]_NLTE=-5.3. This star was discovered in the course of follow-up medium-resolution spectroscopy of extremely metal-poor...
First stars IV.CS 29497-030: Evidence for operation of the s-process at very low metallicity (2003)
Sivarani, T., Bonifacio, P., Molaro, P., Cayrel, R., Spite, M., Spite, F., ...
We present an abundance analysis of the very metal-poor, carbon-enhanced star CS 29497-030. Our results indicate that this unusually hot turnoff star (Teff = 6650K, log g = 3.5) has a metallicity...
Surveying the Inner Halo of the Galaxy with 2MASS-Selected Horizontal Branch Candidates (2003)
Brown, Warren R., Geller, M. J., Kenyon, S. J., Beers, T. C., Kurtz, M. J., Roll, J. B.
We use 2MASS photometry to select blue horizontal branch (BHB) candidates covering the sky |b|>15 deg. A 12.5
Aoki, W., Ryan, S.G., Iwamoto, N., Beers, T.C., Norris, J.E., Ando, H., ...
The Century Survey Galactic Halo Project I: Stellar Spectral Analysis (2003)
Brown, W. R., Prieto, C. Allende, Beers, T. C., Wilhelm, R., Geller, M. J., Kenyon, S. J., ...
The Century Survey Galactic Halo Project is a photometric and spectroscopic survey from which we select relatively blue stars (V-R
New Resources to Explore the Old Galaxy: Mining the SDSS (2003)
Prieto, C. Allende, Beers, T. C., Li, Y., Newberg, H. J., Wilhelm, R., Yanny, B.
The Sloan Digital Sky Survey (SDSS) is collecting photometry and intermediate resolution spectra for ~ 10**5 stars in the thick-disk and stellar halo of the Milky Way. This massive dataset can be...
Sneden, C., Cowan, J. J., Lawler, J. E., Ivans, I. I., Burles, S., Beers, T. C., ...
High-resolution spectra obtained with three ground-based facilities and the Hubble Space Telescope (HST) have been combined to produce a new abundance analysis of CS 22892-052, an extremely...
The r-process in supernova explosions from the collapse of O-Ne-Mg cores (2003)
Wanajo, S., Tamamura, M., Itoh, N., Nomoto, K., Ishimaru, Y., Beers, T. C., ...
We examine r-process nucleosynthesis in a "prompt supernova explosion" from an 8-10 Msun progenitor star, as an alternative scenario to the "neutrino wind" mechanism. In the present model, the...
François, P., Depagne, E., Hill, V., Spite, M., Spite, F., Plez, B., ...
This paper reports detailed abundance analyses for four extremelymetal-poor (XMP) giant stars with [Fe/H]
Elemental abundances of metal poor carbon rich lead star: CS29497-030 (2002)
Sivarani, T., Bonifacio, P., Molaro, P., Cayrel, R., Spite, M., Spite, F., ...
We present here the abundance analysis of a metal poor carbon rich lead star, CS29497-030. High resolution and high signal to noise spectra were obtained using the UVES spectrograph on the 8.2m...
Aoki, W., Honda, S., Beers, T. C., Sneden, C.
We report the first measurement of the isotope fraction of europium (151Eu and 153Eu) for the extremely metal-poor, r-process-enhanced star CS31082-001, based on high-resolution spectra obtained with...
Aoki, W., Norris, J. E., Ryan, S. G., Beers, T. C., Ando, H.
We analyze a high-resolution, high signal-to-noise spectrum of the carbon-rich, extremely metal-poor star CS29498-043, obtained with the Subaru Telescope High Dispersion Spectrograph. We find its...
A Subaru/HDS study of Lead (Pb) abundances in eight s-process-element-rich, metal-poor stars (2002)
Aoki, W., Ryan, S. G., Norris, J. E., Beers, T. C., Ando, H.
We report the abundances of neutron-capture elements in eight carbon-rich, metal-poor (-2.7=
Depagne, E., Hill, V., Spite, M., Spite, F., Plez, B., Beers, T. C., ...
CS 22949--037 is one of the most metal-poor giants known ([Fe/H]$ \approx-4.0$), and it exhibits large overabundances of carbon and nitrogen (Norris et al.). Using VLT-UVES spectra of unprecedented...
Hill, V., Plez, B., Cayrel, R., Beers, T. C., Nordström, B., Andersen, J., ...
We present a high-resolution spectroscopic analysis of the bright (V=11.7), extreme halo giant CS31082-001 ([Fe/H] = -2.9), obtained in an ESO-VLT Large Programme dedicated to very metal-poor stars....
Hill, V., Plez, B., Cayrel, R., Beers, T. C., Nordström, Birgitta, Andersen, J., ...
We present a high-resolution ( R= 75 000, S/ N ) spectroscopic analysis of the bright ( V= 11.7), extreme halo giant CS 31082-001([Fe/H] = -2.9), obtained in an ESO-VLT Large Programme dedicated to...
Depagne, E., Hill, V., Spite, M., Spite, F., Plez, B., Beers, T. C., ...
CS 22949-037 is one of the most metal-poor giants known ([Fe/H]~-4.0),and it exhibits large overabundances of carbon and nitrogen (Norris etal.). Using VLT-UVES spectra of unprecedented quality,...
Neutron Capture Elements in s-Process-Rich, Very Metal-Poor Stars (2001)
Aoki, W., Ryan, S.G., Norris, J.E., Beers, T.C., Ando, H., Iwamoto, N., ...
Tuning the Clock: Uranium and Thorium Chronometers Applied to CS 31082-001 (2001)
Toenjes, R., Schatz, H., Pfeiffer, B., Beers, T. C., Cowan, J., ...
We obtain age estimates for the progenitor(s) of the extremely metal-poor ([Fe/H = -2.9) halo star CS 31082-001, based on the recently reported first observation of a Uranium abundance in this (or...
R-process pattern in the Very-Metal-Poor Halo Star CS31082-001 (2001)
Hill, V., Plez, B., Cayrel, R., Beers, T. C.
The very-metal-poor halo star CS31082-001 was discovered to be very strongly r-process-enhanced during the course of a VLT+UVES high-resolution follow-up of metal-poor stars identified in the HK...
Abundances and Evolution of Lithium in the Galactic Halo and Disk (2001)
Ryan, S.G., Kajino, T., Beers, T.C., Suzuki, T.K., Romano, D., Matteucci, F., ...
Determination of [O/Fe] in BD +23 3130 from ESO VLT-UVES observations (2001)
Cayrel, R., Andersen, J., Barbuy, B., Beers, T. C., Bonifacio, P., François, P., ...
We report a new determination of [O/Fe, the relative logarithmicabundance of O/Fe with respect to the Sun, for the very metal-poor starBD+23 3130 ([Fe/H=-2.6). The value was derived from the...
Measurement of stellar age from uranium decay (2001)
Cayrel, R., Hill, V., Beers, T. C., Barbuy, B., Spite, M., Spite, F., ...
The ages of the oldest stars in the Galaxy indicate when star formationbegan, and provide a minimum age for the Universe. Radioactive dating ofmeteoritic material and stars relies on comparing the...
Cayrel, R., Spite, M., Spite, F., Hill, V., Primas, F., François, P., ...
Not Available
s- and r-process elements in two very metal-poor stars. (2001)
Ryan, S.G., Aoki, W., Blake, L.A.J., Norris, J.E., Beers, T.C., Gallino, R., ...
Metallicity estimates for A-, F-, and G-type stars from the Edinburgh-Cape blue object survey (2000)
Beers, T. C., Rossi, S., O'Donoghue, D., Kilkenny, D., Stobie, R. S., Koen, C., ...
The Edinburgh-Cape Blue Object Survey is an ongoing project to identify and analyse a large sample of hot stars selected initially on the basis of photographic colours (down to a magnitude limit...
Bonifacio, P., Monai, S., Beers, T. C.
We report photoelectric UBV data for 268 metal-poor candidates chosen from the northern HK objective-prism/interference-filter survey of Beers and colleagues. Over 40 % of the stars have been...
Prieto, C. Allende, Rebolo, R., Lopez, R. J. Garcia, Serra-Ricart, M., Beers, T. C., Rossi, S., ...
With the dual aims of enlarging the list of extremely metal-poor stars identified in the Galaxy, and boosting the numbers of moderately metal-deficient stars in directions that sample the rotational...
Aoki, W., Norris, J. E., Ryan, S. G., Beers, T. C., Ando, H.
We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other neutron-capture...
Beers, T. C., Chiba, M., Yoshii, Y., Platais, I., Hanson, R. B., Fuchs, B., ...
We present a revised catalog of 2106 Galactic stars, selected without kinematic bias, and with available radial velocities, distance estimates, and metal abundances in the range 0.0
(Abbreviated) We present a detailed analysis of the space motions of 1203 solar-neighborhood stars with metal abundances [Fe/H]
Primordial Lithium and Big Bang Nucleosynthesis. (2000)
Ryan, S.G., Beers, T.C., Olive, K.A., Fields, B.D., Norris, J.E.
Finding the First Stars: The Hamburg/ESO Objective Prism Survey (1999)
Christlieb, N., Reimers, D., Wisotzki, L., Reetz, J., Gehren, T., Beers, T. C.
We report on a search for extremely metal-poor ([Fe/H]
Primordial Lithium and Big Bang Nucleosynthesis (1999)
Ryan, S. G., Beers, T. C., Olive, K. A., Fields, B. D., Norris, J. E.
In the standard hot big bang nucleosynthesis (BBN) model the primordial abundances of H, H2, He3, He4, and Li7, fix the baryon density of the universe, $\Omega_b$, via the baryon-to-photon ratio,...
Abell 521: Dynamical analysis of a young cluster (1999)
Maurogordato, S., Proust, D., Beers, T. C., Arnaud, M., Pello, R., Cappi, A., ...
We present the results of a dynamical analysis of the rich X-Ray luminous galaxy cluster Abell 521, and discuss the nature of the arc-like structure first noted by Maurogordato et al. (1996). Our...
Beryllium Abundances in Halo Stars from Keck/HIRES Observations. (1999)
Boesgaard, A.M., Deliyannis, C.P., King, J.R., Ryan, S.G., Vogt, S., Beers, T.C.
Original article can be found at: http://www.iop.org/EJ/journal/aj Copyright American Astronomical Society DOI: 10.1086/300780 [Full text of this article is not available in the UHRA]
Beers, T.C., Rossi, S., Norris, J.E., Ryan, S.G., Shefler, T.
Original article can be found at: http://www.iop.org/EJ/journal/aj Copyright American Astronomical Society DOI: 10.1086/300727 [Full text of this article is not available in the UHRA]
R-process abundances and cosmochronometers in old metal-poor halo stars (1998)
Pfeiffer, B., Cowan, J. J., Sneden, C., Burles, S., ...
Proc. IX. Workshop on Nuclear Astrophysics, Ringberg Castle, Tegernsee, Bavaria; March 1998
CS 22957-027: A carbon-rich extremely-metal-poor star (1997)
Bonifacio, P., Molaro, P., Beers, T. C., Vladilo, G.
We present a high-resolution spectroscopic analysis of the extremely-metal-poor star CS 22957-027, which Beers et al (1992) noted to exhibit a rather strong G-band. For Teff = 4839 K, derived from...
Sommer-Larsen, J., Beers, T. C., Flynn, C., Wilhelm, R., Christensen, P. R.
We re-analyse the kinematics of the system of blue horizontal branch field (BHBF) stars in the Galactic halo (in particular the outer halo), fitting the kinematics with the model of radial and...
NLTE spectral analysis of helium-rich sdO stars from the southern HK survey. (1996)
Drilling, J.S., Napiwotzki, R., Dreizler, S., Heber, U., Beers, T.C.
Subcluster Merger and Galaxy Infall in A2151 (1994)
Bird, C. M., Davis, D. S., Beers, T. C.
We have obtained a 12.5 ksec image of the Hercules Cluster, A2151, with the {\it ROSAT} PSPC. Comparison of the optical and X-ray data suggest the presence of at least three distinct subclusters in...
Nucleosynthesis in the early Galaxy To appear in The Astrophysical Journal
F. Montes, T. C. Beers, J. Cowan, T. Elliot, K. Farouqi, R. Gallino, ...
Recent observations of r-process-enriched metal-poor star abundances reveal a non-uniform abundance pattern for elements Z ≤ 47. Based on non-correlation trends between elemental abundances as a...