Carollo, Daniela, Beers, Timothy C., Chiba, Masashi, Norris, John E., Freeman, Ken C., Lee, Young Sun, ...
The structure and kinematics of the recognized stellar components of the Milky Way are explored, based on well-determined atmospheric parameters and kinematic quantities for 32360 "calibration stars"...
Lithium Abundances of Extremely Metal-Poor Turn-off Stars (2009)
Aoki, Wako, Barklem, Paul S., Beers, Timothy C., Christlieb, Norbert, Inoue, Susumu, Perez, Ana E. Garcia, ...
We have determined Li abundances for eleven metal-poor turn-off stars, among which eight have [Fe/H]
Mapping the Galactic Halo VIII: Quantifying substructure (2009)
Starkenburg, Else, Helmi, Amina, Morrison, Heather L., Harding, Paul, Van Woerden, Hugo, Mateo, Mario, ...
We have measured the amount of kinematic substructure in the Galactic halo using the final data set from the Spaghetti project, a pencil-beam high latitude sky survey. Our sample contains 101...
The abundance spread in the Bootes I dwarf spheroidal galaxy (2009)
Norris, John E., Gilmore, Gerard, Wyse, Rosemary F. G., Wilkinson, Mark I., Belokurov, V., Evans, N. Wyn, ...
We present medium-resolution spectra of 16 radial velocity red-giant members of the low-luminosity Bootes I dwarf spheroidal (dSph) galaxy, that have sufficient S/N for abundance determination, based...
A large C+N+O abundance spread in giant stars of the globular cluster NGC 1851 (2009)
Yong, David, Grundahl, Frank, D'Antona, Francesca, Karakas, Amanda I., Lattanzio, John C., Norris, John E.
Abundances of C, N, and O are determined in four bright red giants that span the known abundance range for light (Na and Al) and s-process (Zr and La) elements in the globular cluster NGC 1851. The...
Yong, David, Melendez, Jorge, Cunha, Katia, Karakas, Amanda I., Norris, John E., Smith, Verne V.
We present abundances of C, N, O, F, Na, and Fe in six giant stars of the tidally disrupted globular cluster NGC 6712. The abundances were derived by comparing synthetic spectra with high resolution...
The Milky Way Tomography with SDSS: II. Stellar Metallicity (2008)
Ivezic, Zeljko, Sesar, Branimir, Juric, Mario, Bond, Nicholas, Dalcanton, Julianne, Rockosi, Constance M., ...
Using effective temperature and metallicity derived from SDSS spectra for ~60,000 F and G type main sequence stars (0.2
Aoki, Wako, Beers, Timothy C., Sivarani, Thirupathi, Marsteller, Brian, Lee, Young Sun, Honda, Satoshi, ...
The chemical compositions of seven Carbon-Enhanced Metal-Poor (CEMP) turn-off stars are determined from high-resolution spectroscopy. Five of them are selected from the SDSS/SEGUE sample of...
The Segue Stellar Parameter Pipeline. II. Validation with galactic globular and open clusters (2008)
Lee, Young Sun, Beers, Timothy C., Sivarani, Thirupathi, Johnson, Jennifer A., An, Deokkeun, Wilhelm, Ronald, ...
We validate the accuracy and precision of the current SEGUE (Sloan Extension for Galactic Understanding and Exploration) Stellar Parameter Pipeline (SSPP), which determines stellar atmospheric...
The Segue Stellar Parameter Pipeline. I. Description and comparison of individual methods (2008)
Lee, Young Sun, Beers, Timothy C., Sivarani, Thirupathi, Allende Prieto, Carlos, Koesterke, Lars, Wilhelm, Ronald, ...
We describe the development and implementation of the Sloan Extension for Galactic Exploration and Understanding (SEGUE) Stellar Parameter Pipeline (SSPP). The SSPP is derived, using multiple...
The milky way tomography with SDSS. II. Stellar metallicity (2008)
Ivezic, Zeljko, Sesar, Branimir, Juric, Mario, Bond, Nicholas, Dalcanton, Julianne, Rockosi, Constance M., ...
Using effective temperature and metallicity derived from SDSS spectra for ~60,000 F- and G-type main-sequence stars (0.2
S- and R-Process Elements in Two Very Metal-Poor Stars (2007)
Sean Ryan Wako, Sean G. Ryan, John E. Norris, Timothy C, Roberto Gallino, ...
. New measurements of neutron-capture elements are presented for two very metal-poor stars ([Fe/H] \Gamma3). One (LP 625-44) has an s-process signature believed to be due to mass transfer from a...
Primordial Lithium And Big Bang Nucleosynthesis (2007)
Sean Ryan Timothy, Timothy C. Beers, Keith A. Olive, Brian D. Fields, John E. Norris
Recent determinations of the abundance of the light-element Li in very metal-poor stars show that its intrinsic dispersion is essentially zero and that the random error in the estimated mean Li...
Detection Of Lead In The Carbon-Rich, Very Metal-Poor Star Lp 625-44: A Strong Constraint On (2007)
Process Nucleosynthesis At, Wako Aoki, John E. Norris, Sean G. Ryan, Timothy C. Beers, Hiroyasu Ando
We report the detection of the Pb i l4057.8 line in the very metal-poor ( ), carbon-rich star, [Fe/H] = #2.7 LP 625-44. We determine the abundance of Pb ( ) and 15 other neutron-capture elements. The...
The Giant Branch of Omega Centauri. The Dependence of Kinematics on Abundance (2007)
John E. Norris, K. C. Freeman, Michel Mayor, Observatoire De Gen`eve, Patrick Seitzer
For a sample of some 400 red giants in the chemically inhomogeneous globular cluster ! Centauri we report correlations between the radial velocities of Mayor et al. (1997), which are accurate to !1...
John E. Norris, Sean G. Ryan, Timothy C. Beers
High-resolution, high signal-to-noise ratio (SS/NT \ 85) spectra have been obtained for Ðve stars, CD
THE ASTROPHYSICAL JOURNAL, 561 346363, 2001 November 1 V (2007)
The American Astronomical, Wako Aoki, Sean G. Ryan, John E. Norris, Timothy C. Beers, Hiroyasu Ando, ...
We report abundance estimates for neutron capture elements, including lead (Pb), and nucleosynthesis models for their origin, in two carbon-rich, very metal-poor stars, LP 625-44 and LP 706-7. These...
Abundances on the Main Sequence of Omega Centauri (2007)
Stanford, Laura M., Da Costa, G. S., Norris, John E.
Abundance ratios of carbon, nitrogen and strontium relative to iron, calculated using spectrum synthesis techniques, are given for a sample of main sequence and turnoff stars that belong to the...
Halo Star Streams in the Solar Neighborhood (2007)
Kepley, Amanda A., Morrison, Heather L., Helmi, Amina, Kinman, T. D., Van Duyne, Jeffrey, Martin, John C., ...
We have assembled a sample of halo stars in the solar neighborhood to look for halo substructure in velocity and angular momentum space. Our sample includes red giants, RR Lyrae, and red horizontal...
HE 0557-4840 - Ultra-Metal-Poor and Carbon-Rich (2007)
Norris, John E., Christlieb, N., Korn, A. J., Eriksson, K., Bessell, M. S., Beers, Timothy C., ...
We report the discovery and high-resolution, high S/N, spectroscopic analysis of the ultra-metal-poor red giant HE 0557-4840, which is the third most heavy-element deficient star currently known. Its...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Thom, Christopher, Beers, Timothy C., Rhee, Jaehyon
We present age estimates for the newly discovered, very r-process-enhanced metal-poor star HE 1523-0901 ([Fe/H] = -2.95) based on the radioactive decay of Th and U. The bright (V = 11.1) giant was...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Thom, Christopher, Beers, Timothy C., Rhee, Jaehyon
We present age estimates for the newly discovered very r-process enhanced metal-poor star HE 1523-0901 ([Fe/H]=-2.95) based on the radioactive decay of Th and U. The bright (V=11.1) giant was found...
Aoki, Wako, Honda, Satoshi, Beers, Timothy C., Takada-Hidai, Masahide, Iwamoto, Nobuyuki, Tominaga, Nozomu, ...
A detailed elemental abundance analysis has been carried out for the very metal-poor ([Fe/H]=-2.7) star BS16934-002, which was identified in our previous work as a star exhibiting large...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Thom, Christopher, Beers, Timothy C., Rhee, Jaehyon, ...
We present age estimates for the newly discovered, very r-process-enhanced metal-poor star HE 1523-0901 ([Fe/H] = -2.95) based on the radioactive decay of Th and U. The bright (V = 11.1) giant was...
Two stellar components in the halo of the Milky Way (2007)
Carollo, Daniela, Beers, Timothy C., Lee, Young Sun, Chiba, Masashi, Norris, John E., Wilhelm, Ronald, ...
The halo of the Milky Way provides unique elemental abundance and kinematic information on the first objects to form in the Universe, and this information can be used to tightly constrain models of...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Thom, Christopher, Beers, Timothy C., Rhee, Jaehyon
We present age estimates for the newly discovered, very r-process-enhanced metal-poor star HE 1523-0901 ([Fe/H] = -2.95) based on the radioactive decay of Th and U. The bright (V = 11.1) giant was...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Thom, Christopher, Beers, Timothy C., Rhee, Jaehyon
We present age estimates for the newly discovered, very r-process-enhanced metal-poor star HE 1523-0901 ([Fe/H] = -2.95) based on the radioactive decay of Th and U. The bright (V = 11.1) giant was...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Thom, Christopher, Beers, Timothy C., Rhee, Jaehyon
We present age estimates for the newly discovered, very r-process-enhanced metal-poor star HE 1523-0901 ([Fe/H] = -2.95) based on the radioactive decay of Th and U. The bright (V = 11.1) giant was...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Thom, Christopher, Beers, Timothy C., Rhee, Jaehyon
We present age estimates for the newly discovered, very r-process-enhanced metal-poor star HE 1523-0901 ([Fe/H] = -2.95) based on the radioactive decay of Th and U. The bright (V = 11.1) giant was...
Chemical Abundance Analysis of the Extremely Metal-Poor Star HE 1300+0157 (2006)
Frebel, Anna, Norris, John E., Aoki, Wako, Honda, Satoshi, Bessell, Michael S., Takada-Hidai, Masahide, ...
We present a detailed chemical abundance analysis of HE 1300+0157, a subgiant with [Fe/H]=-3.9. From a high-resolution, high-S/N Subaru/HDS spectrum we find the star to be enriched in C ([C/Fe]_1D ~...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
We present a sample of 1777 bright (9 < B < 14) metal-poor candidates selected from the Hamburg/ESO Survey (HES). Despite saturation effects present in the red portion of the HES objective-prism...
A Sr-Rich Star on the Main Sequence of Omega Centauri (2006)
Stanford, Laura M., Da Costa, G. S., Norris, John E., Cannon, Russell D.
Abundance ratios relative to iron for carbon, nitrogen, strontium and barium are presented for a metal-rich main sequence star ([Fe/H]=--0.74) in the globular cluster omega Centauri. This star,...
Carbon Enhanced Metal-Poor Stars. I. Chemical Compositions of 26 Stars (2006)
Aoki, Wako, Beers, Timothy C., Christlieb, Norbert, Norris, John E., Ryan, Sean G., Tsangarides, Stelios
The chemical compositions of 26 metal-poor stars that exhibit strong CH and/or C2 molecular bands are determined based on high-resolution spectroscopy. We define carbon-enhanced stars taking account...
Aoki, Wako, Bisterzo, Sara, Gallino, Roberto, Beers, Timothy C., Norris, John E., Ryan, Sean G., ...
We have investigated the abundances of heavy neutron-capture elements, including osmium (Os) and iridium (Ir), in the two Carbon-Enhanced Metal-Poor (CEMP) subgiants CS31062-050 and LP625-44....
A high-resolution spectral analysis of three carbon-enhanced metal-poor stars (2006)
Goswami, Aruna, Aoki, Wako, Beers, Timothy C., Christlieb, Norbert, Norris, John E., Ryan, Sean 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,...
Wyse, Rosemary F. G., Gilmore, Gerard, Norris, John E., Wilkinson, M. I., Kleyna, Jan T., Koch, A., ...
The history of the Milky Way Galaxy is written in the properties of its stellar populations. Here we analyse stars observed as part of surveys of local dwarf spheroidal galaxies, but which from their...
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
Frebel, Anna, Christlieb, Norbert, Norris, John E., Beers, Timothy C., Bessell, Michael S., Rhee, Jaehon, ...
Abstract not available.
The Oxygen Abundance of HE 1327-2326 (2005)
Frebel, Anna, Christlieb, Norbert, Norris, John E., Aoki, Wako, Asplund, Martin
From a newly obtained VLT/UVES spectrum we have determined the oxygen abundance of HE 1327-2326, the most iron-poor star known to date. UV-OH lines yield a 1D LTE abundance of [O/Fe]_OH = 3.7...
Recent observational studies of $\omega$ Centauri by {\it Hubble Space Telescope} have discovered a double main sequence in the color magnitude diagrams (CMDs) of its stellar populations. The stellar...
The Metallicity Distribution Function of the Halo of the Milky Way (2005)
Beers, Timothy C., Christlieb, Norbert, Norris, John E., Bessell, Michael S., Wilhelm, Ronald, Prieto, Carlos Allende, ...
We report on the distribution of metallicities, [Fe/H], for very metal-poor stars in the halo of the Galaxy. Although the primary information on the nature of the Metallicity Distribution Function...
Abundances on the Main Sequence of the Globular Cluster Omega Centauri (2005)
Da Costa, G. S., Stanford, Laura, Norris, John E., Cannon, R. D.
Using the 2dF multi-fibre instrument on the AAT, moderate resolution spectra have been obtained for a large sample of stars on the main sequence and at the turnoff in the unusual globular cluster...
Clewley, L., Warren, S. J., Hewett, P. C., Norris, John. E., Wilkinson, M. I., Evans, N. W.
We present VLT-FORS1 spectra of a sample of 34 faint 20.0 < g* < 21.1 A-type stars selected from the Sloan Digital Sky Survey Early Data Release, with the goal of measuring the velocity dispersion of...
Aoki, Wako, Honda, Satoshi, Beers, Timothy C., Kajino, Toshitaka, Ando, Hiroyasu, Norris, John E., ...
Elemental abundance measurements have been obtained for a sample of 18 very metal-poor stars using spectra obtained with the Subaru Telescope High Dispersion Spectrograph. Seventeen stars, among...
Nucleosynthetic signatures of the first stars (2005)
Frebel, Anna, Aoki, Wako, Christlieb, Norbert, Ando, Hiroyasu, Asplund, Martin, Barklem, Paul S., ...
The chemically most primitive stars provide constraints on the nature of the first stellar objects that formed in the Universe; elements other than hydrogen, helium and traces of lithium within these...
Clewley, L., Warren, S. J., Hewett, P. C., Norris, John E., Evans, N. W.
This is the second in a series of papers presenting a new calculation of the mass of the Galaxy based on radial velocities and distances for a sample of faint 16 < B < 21.3 field blue...
Oxygen Overabundance in the Extremely Iron-Poor Star CS29498-043 (2004)
Aoki, Wako, Norris, John E., Ryan, Sean G., Beers, Timothy C., Christlieb, Norbert, Tsangarides, Stelios, ...
An abundance analysis for the carbon-enhanced, extremely iron-poor ([Fe/H] -3.5) star CS29498-043 has been obtained using new high-resolution, high signal-to-noise spectra from the Subaru Telescope....
Aoki, Wako, Ryan, Sean G., Iwamoto, Nobuyuki, Beers, Timothy C., Norris, John E., Ando, Hiroyasu, ...
We report on the first measurement of the Eu isotope fractions (151Eu and 153Eu) in s-process-element-enhanced, metal-poor stars. We use these ratios to investigate the 151Sm branching of s-process...
Distant field BHB stars and the mass of the Galaxy I: Classification of halo A-type stars (2002)
Clewley, L., Warren, S. J., Hewett, P. C., Norris, John E., Peterson, R. C., Evans, N. W.
This is the first in a series of three papers presenting a new calculation of the mass of the Galaxy based on radial velocities and distances measured for a sample of some 100 faint 16 < B < 20 field...
Deciphering The Last Major Invasion of the Milky Way Galaxy (2002)
Gilmore, Gerard, Wyse, Rosemary F. G., Norris, John E.
We present first results from a spectroscopic survey of 2000 F/G stars 0.5--5kpc from the Galactic plane, obtained with the 2dF facility on the AAT. These data show the mean rotation velocity of the...
Beers, Timothy C., Drilling, John S., Rossi, Silvia, Chiba, Masashi, Rhee, Jaehyon, Fuhrmeister, Birgit, ...
We report medium-resolution (1-2 A) spectroscopy and broadband (UBV) photometry for a sample of 39 bright stars (the majority of which are likely to be giants) selected as metal-deficient candidates...
Aoki, Wako, Norris, John E., Ryan, Sean G., Beers, Timothy C., Ando, Hiroyasu
We report on an analysis of the chemical composition of five carbon-rich, very metal-poor stars based on high-resolution spectra. One star, CS22948-027, exhibits very large overabundances of carbon,...
Norris, John E., Ryan, Sean G., Beers, Timothy C.
High-resolution, high-signal-to-noise ( = 85) spectra have been obtained for five stars -- CD-24:17504, CD-38:245, CS 22172-002, CS 22885-096, and CS 22949-037 -- having [Fe/H] < -3.5 according to...
Neutron Capture Elements in s-Process-Rich, Very Metal-Poor Stars (2001)
Aoki, Wako, Ryan, Sean G., Norris, John E., Beers, Timothy C., Ando, Hiroyasu, Iwamoto, Nobuyuki, ...
We report abundance estimates for neutron-capture elements, including lead (Pb), and nucleosynthesis models for their origin, in two carbon-rich, very metal-poor stars, LP625-44 and LP706-7. These...
Mapping the Galactic Halo III. Simulated Observations of Tidal Streams (2000)
Harding, Paul, Morrison, Heather L., Olszewski, Edward W., Arabadjis, John, Mateo, Mario, Dohm-Palmer, R. C., ...
We have simulated the evolution of tidal debris in the Galactic halo in order to guide our ongoing survey to determine the fraction of halo mass accreted via satellite infall. Contrary to naive...
s- and r-process elements in two very metal-poor stars (2000)
Ryan, Sean G., Aoki, Wako, Blake, Lisa A. J., Norris, John E., Beers, Timothy C., Gallino, Roberto, ...
New measurements of neutron-capture elements are presented for two very metal-poor stars ([Fe/H] ~ -3). One (LP 625-44) has an s-process signature believed to be due to mass transfer from a...
Extremely Metal-Poor Stars. VII. The Most Metal-Poor Dwarf, CS 22876-032 (2000)
Norris, John E., Beers, Timothy C., Ryan, Sean G.
We report high-resolution, high-signal-to-noise, observations of the extremely metal-poor double-lined spectroscopic binary CS 22876-032. The system has a long period : P = 424.7 $\pm$ 0.6 days. It...
Mapping the Galactic Halo I. The `Spaghetti' Survey (2000)
Morrison, Heather L., Mateo, Mario, Olszewski, Edward W., Harding, Paul, Dohm-Palmer, R. C., Freeman, Kenneth C., ...
We describe a major survey of the Milky Way halo designed to test for kinematic substructure caused by destruction of accreted satellites. We use the Washington photometric system to identify halo...
Extremely Metal-Poor Stars. VII. The Most Metal-Poor Dwarf, CS 22876-032 (2000)
John E. Norris, Timothy C. Beers, Sean G. Ryan
We report high-resolution, high signal-to-noise observations of the extremely metal-poor double-lined spectroscopic binary CS 22876[032. The system has a long period : P\ 424.7 ^ 0.6 days. It...
The Spectroscopic Age of 47 Tuc (1999)
Gibson, Brad K., Madgwick, Darren S., Jones, Lewis A., Da Costa, Gary S., Norris, John E.
High signal-to-noise integrated spectra of the metal-rich globular cluster 47 Tuc, spanning the H-gamma(HR) and Fe4668 line indices, have been obtained. The combination of these indices has been...
The Spite Lithium Plateau: Ultra-Thin but Post-Primordial (1999)
Ryan, Sean G., Norris, John E., Beers, Timothy C.
We have studied 23 very metal-poor field turnoff stars, specifically chosen to enable a precise measurement of the dispersion in the lithium abundance of the Spite Li plateau. We concentrated on...
The Spite Lithium Plateau: Ultrathin But Postprimordial (1999)
Sean G. Ryan, John E. Norris, Timothy C. Beers
We have studied 23 very metal-poor eld turno+ stars, specically chosen to enable a precise measurement of the dispersion in the lithium abundance of the Spite Li plateau. We concentrated on stars...