Publications (39)
New ATLAS9 And MARCS Model Atmosphere Grids for the Apache Point Observatory Galactic Evolution Experiment (APOGEE)
Sz. Mészáros, C. Allende Prieto, B. Edvardsson +8
We present a new grid of model photospheres for the SDSS-III/APOGEE survey of stellar populations of the Galaxy, calculated using the ATLAS9 and MARCS codes. New opacity distributi…
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs
J. C. Wilson, F. R. Hearty, M. F. Skrutskie +86
We describe the design and performance of the near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrogra…
New H-band Stellar Spectral Libraries for the SDSS-III/APOGEE survey
O. Zamora, D. A. Garcia-Hernandez, C. Allende Prieto +18
The Sloan Digital Sky Survey--III (SDSS--III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) has obtained high resolution (R 22,500), high signal-to-noise r…
Target Selection for the SDSS-IV APOGEE-2 Survey
G. Zasowski, R. E. Cohen, S. D. Chojnowski +34
APOGEE-2 is a high-resolution, near-infrared spectroscopic survey observing roughly 300,000 stars across the entire sky. It is the successor to APOGEE and is part of the Sloan Digi…
The SDSS-III APOGEE Radial Velocity Survey of M dwarfs I: Description of Survey and Science Goals
R. Deshpande, C. H. Blake, C. F. Bender +28
We are carrying out a large ancillary program with the SDSS-III, using the fiber-fed multi-object NIR APOGEE spectrograph, to obtain high-resolution H-band spectra of more than 120…
Manganese in dwarf spheroidal galaxies
P. North, G. Cescutti, P. Jablonka +10
We provide manganese abundances (corrected for the effect of the hyperfine structure) for a large number of stars in the dwarf spheroidal galaxies Sculptor and Fornax, and for a sm…
Chemodynamics of the Milky Way. I. The first year of APOGEE data
F. Anders, C. Chiappini, B. X. Santiago +38
We investigate the chemo-kinematic properties of the Milky Way disc by exploring the first year of data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), an…
VLT/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies: II. Implications for Understanding Galaxy Evolution
Eline Tolstoy, K. A. Venn, M. Shetrone +4
We have used UVES on VLT-UT2 to take spectra of 15 individual red giant stars in the centers of four nearby dwarf spheroidal galaxies: Sculptor, Fornax, Carina and Leo I. We measur…
Galactic Doppelganger: The chemical similarity among field stars and among stars with a common birth origin
M. Ness, H-W. Rix, David W. Hogg +9
We explore to which extent stars within Galactic disk open clusters resemble each other in the high-dimensional space of their photospheric element abundances, and contrast this wi…
Cosmic variance in [O/Fe] in the Galactic disk
S. Bertran de Lis, C. Allende Prieto, S. R. Majewski +11
We examine the distribution of the [O/Fe] abundance ratio in stars across the Galactic disk using H-band spectra from the Apache Point Galactic Evolution Experiment (APOGEE). We mi…
Extremely metal-poor stars in classical dwarf spheroidal galaxies: Fornax, Sculptor and Sextans
M. Tafelmeyer, P. Jablonka, V. Hill +13
We present the results of a dedicated search for extremely metal-poor stars in the Fornax, Sculptor and Sextans dSphs. Five stars were selected from two earlier VLT/Giraffe and HET…
Atypical Mg-poor Milky Way field stars with globular cluster second-generation like chemical patterns
J. G. Fernández-Trincado, O. Zamora, D. A. Garcia-Hernandez +48
We report the peculiar chemical abundance patterns of eleven atypical Milky Way (MW) field red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (A…
VLT/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies: I. Nucleosynthesis and Abundance Ratios
M. Shetrone, K. A. Venn, E. Tolstoy +3
We have used UVES on VLT-UT2 to take spectra of 15 red giants in the Sculptor, Fornax, Carina and Leo I dwarf spheroidal galaxies. We measure the abundances of alpha, iron peak, s…
The blue straggler V106 in NGC6791: A prototype progenitor of old single giants masquerading as young
K. Brogaard, S. M. Christiansen, F. Grundahl +18
We determine the properties of the binary star V106 in the old open cluster NGC6791. We identify the system to be a blue straggler cluster member by using a combination of ground-b…
A view of the H-band light-element chemical patterns in Globular Clusters under the AGB self-enrichment scenario
F. Dell'Agli, D. A. GarcÃa-Hernández, P. Ventura +7
We discuss the self-enrichment scenario by AGB stars for the formation of multiple populations in globular clusters (GCs) by analyzing data set of giant stars observed in 9 Galacti…
The chemical evolution of the dwarf Spheroidal galaxy Sextans
R. Theler, P. Jablonka, R. Lucchesi +11
We present the analysis of the FLAMES dataset targeting the central 25 arcmin region of the Sextans dSph. This dataset is the third major part of the high resolution spectroscopic…
Follow-up observations of extremely metal-poor stars identified from SDSS
D. S. Aguado, C. Allende Prieto, J. I. González Hernández +5
The most metal-poor stars in the Milky Way witnessed the early phases of formation of the Galaxy, and have chemical compositions that are close to the pristine mixture from Big Ban…
Target Selection for the Apache Point Observatory Galactic Evolution Experiment (APOGEE)
G. Zasowski, Jennifer A. Johnson, P. M. Frinchaboy +43
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution infrared spectroscopic survey spanning all Galactic environments (i.e., bulge, disk, and ha…
The SEGUE Stellar Parameter Pipeline. III. Comparison with High-Resolution Spectroscopy of SDSS/SEGUE Field Stars
C. Allende Prieto, T. Sivarani, T. C. Beers +14
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…
Mapping the Interstellar Medium with Near-Infrared Diffuse Interstellar Bands
G. Zasowski, B. Menard, D. Bizyaev +10
We map the distribution and properties of the Milky Way's interstellar medium as traced by diffuse interstellar bands (DIBs) detected in near-infrared stellar spectra from the SDSS…
Photometry and spectroscopy of multiple populations along the AGB of NGC2808 and NGC6121 (M4)
A. F. Marino, A. P. Milone, D. Yong +8
We present a photometric and spectroscopic study of multiple populations along the asymptotic-giant branch (AGB) of the intermediate-metallicity globular clusters (GCs) NGC2808 and…
Discovery of a Metal-Poor Field Giant with a Globular Cluster Second-Generation Abundance Pattern
J. G. Fernández-Trincado, A. C. Robin, E. Moreno +31
We report on detection, from observations obtained with the APOGEE spectroscopic survey, of a metal-poor ([Fe/H] dex) field giant star with an extreme Mg-Al abundance rati…
A high resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
B. Letarte, V. Hill, E. Tolstoy +13
For the first time we show the detailed late-stage chemical evolution history of small nearby dwarf spheroidal galaxy in the Local Group. We present the results of a high resolutio…
The First HET Planet: A Companion to HD 37605
W. D. Cochran, M. Endl, B. McArthur +13
We report the first detection of a planetary-mass companion to a star using the High Resolution Spectrograph (HRS) of the Hobby-Eberly Telescope (HET). The HET-HRS now gives routin…
A homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code. I. The Northern clusters
T. Masseron, D. A. GarcÃa-Hernández, Sz. Mészáros +12
We analyze a large sample of 885 GCs giants from the APOGEE survey. We used the Cannon results to separate the red giant branch and the asymptotic giant branch stars, not only allo…
Chemical Composition of Extremely Metal-Poor Stars in the Sextans Dwarf Spheroidal Galaxy
W. Aoki, N. Arimoto, K. Sadakane +15
Chemical abundances of six extremely metal-poor ([Fe/H]<-2.5) stars in the Sextans dwarf spheroidal galaxy are determined based on high resolution spectroscopy (R=40,000) with the…
A new view of the dwarf spheroidal satellites of the Milky Way from VLT/FLAMES: Where are the very metal poor stars?
Amina Helmi, M. J. Irwin, E. Tolstoy +13
As part of the Dwarf galaxies Abundances and Radial-velocities Team (DART) program, we have measured the metallicities of a large sample of stars in four nearby dwarf spheroidal ga…
A Planetary Mass Companion to the K0 Giant HD 17092
A. Niedzielski, M. Konacki, A. Wolszczan +6
We report the discovery of a substellar-mass companion to the K0-giant HD 17092 with the Hobby-Eberly Telescope. In the absence of any correlation of the observed 360-day periodici…
Calibrations of Atmospheric Parameters Obtained from the First Year of SDSS-III APOGEE Observations
Sz. Mészáros, J. Holtzman, A. E. GarcÃa Pérez +25
The SDSS-III Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a three year survey that is collecting 100,000 high-resolution spectra in the near-IR across multipl…
Evidence of AGB pollution in Galactic globular clusters from the Mg-Al anticorrelations observed by the APOGEE survey
P. Ventura, D. A. GarcÃa--Hernández, F. Dell'Agli +8
We study the formation of multiple populations in globular clusters (GC), under the hypothesis that stars in the second generation formed from the winds of intermediate-mass stars,…
H-band discovery of additional Second-Generation stars in the Galactic Bulge Globular Cluster NGC 6522 as observed by APOGEE and Gaia
José G. Fernández-Trincado, O. Zamora, Diogo Souto +34
We present elemental abundance analysis of high-resolution spectra for five giant stars, deriving Fe, Mg, Al, C, N, O, Si and Ce abundances, and spatially located within the innerm…
What is the Milky Way outer halo made of? High resolution spectroscopy of distant red giants
G. Battaglia, P. North, P. Jablonka +5
In a framework where galaxies form hierarchically, extended stellar haloes are predicted to be an ubiquitous feature around Milky Way-like galaxies and to consist mainly of the shr…
Clear evidence for the presence of second-generation asymptotic giant branch stars in metal-poor Galactic globular clusters
D. A. Garcia-Hernandez, Sz. Meszaros, M. Monelli +5
Galactic globular clusters (GCs) are known to host multiple stellar populations: a first generation with a chemical pattern typical of halo field stars and a second generation (SG)…
APOGEE: The Apache Point Observatory Galactic Evolution Experiment
C. Allende Prieto, S. R. Majewski, R. Schiavon +8
APOGEE is a large-scale, NIR, high-resolution (R~20,000) spectroscopic survey of Galactic stars. It is one of the four experiments in SDSS-III. Because APOGEE will observe in the H…
VLT/FLAMES spectroscopy of red giant branch stars in the Fornax dwarf spheroidal galaxy
B. Lemasle, T. de Boer, V. Hill +13
Fornax is one of the most massive dwarf spheroidal galaxies in the Local Group. The Fornax field star population is dominated by intermediate age stars but star formation was going…
Extinction Maps towards the Milky Way Bulge: 2D and 3D Tests with APOGEE
M. Schultheis, G. Zasowski, C. Allende Prieto +15
Galactic interstellar extinction maps are powerful and necessary tools for Milky Way structure and stellar population analyses, particularly toward the heavily-reddened bulge and i…
Homogeneity in the early chemical evolution of the Sextans dwarf Spheroidal galaxy
R. Lucchesi, C. Lardo, F. Primas +10
We present the high-resolution spectroscopic analysis of two new extremely metal-poor stars (EMPS) candidates in the dwarf spheroidal galaxy Sextans. These targets were pre-selecte…
Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era
C. Charbonnel, N. Lagarde, G. Jasniewicz +7
Lithium is extensively known to be a good tracer of non-standard mixing processes occurring in stellar interiors. We present the results of a new large Lithium survey in red giant…
The early days of the Sculptor dwarf spheroidal galaxy
P. Jablonka, P. North, L. Mashonkina +11
We present the high resolution spectroscopic study of five -3.9<=[Fe/H]<=-2.5 stars in the Local Group dwarf spheroidal, Sculptor, thereby doubling the number of stars with compara…