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1. Inclination- and dust-corrected galaxy parameters: Bulge-to-disc ratios and size-luminosity relations

Author

Graham, Alister W. and Worley, C. C.

Subjects
Astrophysics
Abstract

While galactic bulges may contain no significant dust of their own, the dust within galaxy discs can strongly attenuate the light from their embedded bulges. Furthermore, such dust inhibits the ability of observationally-determined inclination corrections to recover intrinsic (i.e. dust free) galaxy parameters. Using the sophisticated 3D radiative transfer model of Popescu et al. and Tuffs et al., together with Driver et al.'s recent determination of the average face-on opacity in nearby disc galaxies, we provide simple equations to correct (observed) disc central surface brightnesses and scalelengths for the effects of both inclination and dust in the B, V, I, J and K passband. We then collate and homogenise various literature data sets and determine the typical intrinsic scalelengths, central surface brightnesses and magnitudes of galaxy discs as a function of morphological type. All galaxies have been carefully modelled in their respective papers with a Sersic bulge plus an exponential disc. Using the bulge magnitude corrections from Driver et al., we additionally derive the average, dust-corrected, bulge-to-disc flux ratio as a function of galaxy type. With values typically less than 1/3, this places somewhat uncomfortable constraints on some current semi-analytic simulations. Typical bulge sizes, profile shapes, surface brightnesses and deprojected densities are provided. Finally, given the two-component nature of disc galaxies, we present luminosity-size and (surface brightness)-size diagrams for discs and bulges. We also show that the distribution of elliptical galaxies in the luminosity-size diagram is not linear but strongly curved., Comment: MNRAS, accepted for publication

Published
2008
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2. s- and r-process element abundances in the CMD of 47 Tucanae using the Robert Stobie Spectrograph on SALT

Author

Worley, C. C., Cottrell, P. L., and de Boer, E. C. Wylie

Subjects
Astrophysics
Abstract

A recent study by Wylie et al 2006 has revealed that s-process element abundances are enhanced relative to iron in both red giant branch and asymptotic giant branch stars of 47 Tucanae. A more detailed investigation into s-process element abundances throughout the colour-magnitude diagram of 47 Tucanae is vital in order to determine whether the observed enhancements are intrinsic to the cluster. This paper explores this possibility through observational and theoretical means. The visibility of s- and r-process element lines in synthetic spectra of giant and dwarf stars throughout the colour magnitude diagram of 47 Tucanae has been explored. It was determined that a resolving power of 10 000 was sufficient to observe s-process element abundance variations in globular cluster giant branch stars. These synthetic results were compared with the spectra of eleven 47 Tucanae giant branch stars observed during the performance verification of the Robert Stobie Spectrograph on the Southern African Large Telescope. Three s-process elements, Zr, Ba, Nd, and one r-process element, Eu, were investigated. No abundance variations were found such that [X/Fe] = 0.0 +/- 0.5 dex. It was concluded that this resolving power, R ~ 5000, was not sufficient to obtain exact abundances but upper limits on the s-process element abundances could be determined., Comment: 7 pages, 11 figures

Published
2008
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3. The gaia -ESO survey: calibration strategy

Author

Pancino, E., Lardo, C., Altavilla, G., Marinoni, S., Ragaini, S., Cocozza, G., Bellazzini, M., Sabbi, E., Zoccali, M., Donati, P., Heiter, U., Koposov, S. E., Blomme, R., Morel, T., Símon-Díaz, S., Lobel, A., Soubiran, C., Montalban, J., Valentini, M., Casey, A. R., Blanco-Cuaresma, S., Jofré, P., Worley, C. C., Magrini, L., Hourihane, A., François, P., Feltzing, S., Gilmore, G., Randich, S., Asplund, M., Bonifacio, P., Drew, J. E., Jeffries, R. D., Micela, G., Vallenari, A., Alfaro, E. J., Allende Prieto, C., Babusiaux, C., Bensby, T., angela Bragaglia, Flaccomio, E., Hambly, N., Korn, A. J., Lanzafame, A. C., Smiljanic, R., Eck, S., Walton, N. A., Bayo, A., Carraro, G., Costado, M. T., Damiani, F., Edvardsson, B., Franciosini, E., Frasca, A., Lewis, J., Monaco, L., Morbidelli, L., Prisinzano, L., Sacco, G. G., Sbordone, L., Sousa, S. G., Zaggia, S., Koch, A., Ministero dell'Istruzione, dell'Università e della Ricerca, Knut and Alice Wallenberg Foundation, European Research Council, Swedish National Space Board, Belgian Science Policy Office, National Science Centre (Poland), European Science Foundation, Ministerio de Economía y Competitividad (España), Pancino E., Lardo C., Altavilla G., Marinoni S., Ragaini S., Cocozza G., Bellazzini M., Sabbi E., Zoccali M., Donati P., Heiter U., Koposov S.E., Blomme R., Morel T., Simon-Diaz S., Lobel A., Soubiran C., Montalban J., Valentini M., Casey A.R., Blanco-Cuaresma S., Jofre P., Worley C.C., Magrini L., Hourihane A., Francois P., Feltzing S., Gilmore G., Randich S., Asplund M., Bonifacio P., Drew J.E., Jeffries R.D., Micela G., Vallenari A., Alfaro E.J., Allende Prieto C., Babusiaux C., Bensby T., Bragaglia A., Flaccomio E., Hambly N., Korn A.J., Lanzafame A.C., Smiljanic R., Van Eck S., Walton N.A., Bayo A., Carraro G., Costado M.T., Damiani F., Edvardsson B., Franciosini E., Frasca A., Lewis J., Monaco L., Morbidelli L., Prisinzano L., Sacco G.G., Sbordone L., Sousa S.G., Zaggia S., Koch A., Institut national de recherche et de sécurité (Vandoeuvre lès Nancy) (INRS ( Vandoeuvre lès Nancy)), Royal Observatory of Belgium [Brussels] (ROB), Science et Ingénierie des Matériaux et Procédés (SIMaP ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), M2A 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Leibniz-Institut für Astrophysik Potsdam (AIP), Focas Research Institute, Dublin Institute of Technology, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), School of Physics, Astronomy and Mathematics [Hatfield], University of Hertfordshire [Hatfield] (UH), INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), Economía Política y Hacienda Pública, Estadística Económica y Empresarial y Política Económica, Universidad de Castilla-La Mancha (UCLM), Department of Astronomy and Space Physics [Uppsala], Uppsala University, INAF - Osservatorio Astrofisico di Catania (OACT), Institut d'Astronomie et d'Astrophysique, Université libre de Bruxelles (ULB), University of Turin, Department of Physiology and Pharmacology, Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]-Réseau International des Instituts Pasteur (RIIP)-Institut Pasteur, Fondation Cenci Bolognetti - Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Réseau International des Instituts Pasteur (RIIP), Pôle Gérontologie, and Centre Hospitalier Universitaire de Nice (CHU Nice)

Subjects
Stars: abundance, Milky Way, FOS: Physical sciences, Techniques: spectroscopic, Astrophysics, Parameter space, Surveys, 01 natural sciences, Spectral line, surveys, 0103 physical sciences, Calibration, Emission spectrum, Survey, 010303 astronomy & astrophysics, Galaxy: general, Solar and Stellar Astrophysics (astro-ph.SR), QC, general [Galaxy], QB, Physics, [PHYS]Physics [physics], Observational error, 010308 nuclear & particles physics, Techniques: radial velocitie, Stars: abundances, Astronomy and Astrophysics, Ranging, radial velocities [techniques], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, abundances [stars], Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Techniques: radial velocities, stars: abundances, techniques: spectroscopic, techniques: radial velocities, spectroscopic [techniques], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The Gaia-ESO survey (GES) is now in its fifth and last year of observations and has produced tens of thousands of high-quality spectra of stars in all Milky Way components. This paper presents the strategy behind the selection of astrophysical calibration targets, ensuring that all GES results on radial velocities, atmospheric parameters, and chemical abundance ratios will be both internally consistent and easily comparable with other literature results, especially from other large spectroscopic surveys and from Gaia. The calibration of GES is particularly delicate because of (i) the large space of parameters covered by its targets, ranging from dwarfs to giants, from O to M stars; these targets have a large wide of metallicities and also include fast rotators, emission line objects, and stars affected by veiling; (ii) the variety of observing setups, with different wavelength ranges and resolution; and (iii) the choice of analyzing the data with many different state-of-the-art methods, each stronger in a different region of the parameter space, which ensures a better understanding of systematic uncertainties. An overview of the GES calibration and homogenization strategy is also given, along with some examples of the usage and results of calibrators in GES iDR4, which is the fourth internal GES data release and will form the basis of the next GES public data release. The agreement between GES iDR4 recommended values and reference values for the calibrating objects are very satisfactory. The average offsets and spreads are generally compatible with the GES measurement errors, which in iDR4 data already meet the requirements set by the main GES scientific goals.© ESO, 2017., This work was partly supported by the European Union FP7 program through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR) in the form of the grant >Premiale VLT 2012>. The results presented here benefit from discussions held during the Gaia-ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. S.F. and T.B. acknowledge the support from the New Milky Way project funded by a grant from the Knut and Alice Wallenberg foundation. C.L. gratefully acknowledges financial support from the European Research Council (ERC-CoG-646928, Multi-Pop, PI: N. Bastian). U.H. and A.J.K acknowledge support from the Swedish National Space Board (Rymdstyrelsen). The research of A.L. has been subsidized by the Belgian Federal Science Policy Office under contract No. BR/143/A2/BRASS. R.S. acknowledges support by the National Science Center of Poland through grant 2014/15/B/ST9/03981. C.A.P. is thankful for support from the Spanish Ministry of Economy and Competitiveness (MINECO) through grant AYA2014-56359-P.J.M. acknowledges support from the ERC Consolidator Grant funding scheme (project STARKEY, G.A. No. 615604). T.M. acknowledges financial support from Belspo for contract PRODEX Gaia-DPAC. S.G.S acknowledges the support by Fundacao para a Ciencia e Tecnologia (FCT) through national funds and a research grant (project ref. UID/FIS/04434/2013, and PTDC/FIS-AST/7073/2014). S.G.S. also acknowledge the support from FCT through Investigador FCT contract of reference IF/00028/2014 and POPH/FSE (EC) by FEDER funding through the program >Programa Operacional de Factores de Competitividade - COMPETE>. L.S. acknowledges support by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics (MAS). M.Z. acknowledges support by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics (MAS), by Fondecyt Regular 1150345 and by the BASAL CATA PFB-06. E.J.A. and M.T.C acknowledge the financial support from the Spanish Ministerio de Economia y Competitividad, through grant AYA2013-40611-P.S.Z. acknowledge the support from the INAF grant >PRIN INAF 2014>, >Star won't tell their ages to Gaia, Galactic Archaelogy with wide-area asterosismic>.

Published
2017

4. The Gaia-ESO Survey: Structural and dynamical properties of the young cluster Chamaeleon i

Author

Sacco, G. G., Spina, L., Randich, S., Palla, F., Parker, J., Jeffries, D., Jackson, R., Meyer, R., Mapelli, M., Lanzafame, C., Bonito, R., Damiani, F., Franciosini, E., Frasca, A., Klutsch, A., Prisinzano, L., Tognelli, E., Degl’Innocenti, S., Prada Moroni, P. G., Alfaro, J., Micela, G., Prusti, T., Barrado, D., Biazzo, K., Bouy, H., Bravi, L., Lopez-Santiago, J., Wright, J., Bayo, A., Gilmore, G., Bragaglia, A., Flaccomio, E., Koposov, S. E., Pancino, E., Casey, A. R., Costado, M. T., Donati, P., Hourihane, A., Jofré, P., Lardo, C., Lewis, J., Magrini, L., Monaco, L., Morbidelli, L., Sousa, S. G., Worley, C. C., Zaggia, S., Parker, R. J., Jeffries, R. D., Meyer, M. R., Lanzafame, A. C., Degl'Innocenti, S., Alfaro, E. J., Wright, N. J., Gilmore, Gerard [0000-0003-4632-0213], Koposov, Sergey [0000-0003-2644-135X], Worley, Clare [0000-0001-9310-2898], Apollo - University of Cambridge Repository, Sacco G.G., Spina L., Randich S., Palla F., Parker R.J., Jeffries R.D., Jackson R., Meyer M.R., Mapelli M., Lanzafame A.C., Bonito R., Damiani F., Franciosini E., Frasca A., Klutsch A., Prisinzano L., Tognelli E., Degl'Innocenti S., Prada Moroni P.G., Alfaro E.J., Micela G., Prusti T., Barrado D., Biazzo K., Bouy H., Bravi L., Lopez-Santiago J., Wright N.J., Bayo A., Gilmore G., Bragaglia A., Flaccomio E., Koposov S.E., Pancino E., Casey A.R., Costado M.T., Donati P., Hourihane A., Jofre P., Lardo C., Lewis J., Magrini L., Monaco L., Morbidelli L., Sousa S.G., Worley C.C., Zaggia S., Ministero dell'Istruzione, dell'Università e della Ricerca, Istituto Nazionale di Astrofisica, European Research Council, Fundação para a Ciência e a Tecnologia (Portugal), Pôle Gérontologie, Centre Hospitalier Universitaire de Nice (CHU Nice), Muséum national d'Histoire naturelle (MNHN), Watershed Associates Ltd, Istituto di Astrofisica Spaziale e Fisica cosmica - Palermo (IASF-Pa), Istituto Nazionale di Astrofisica (INAF), University of Turin, INAF - Osservatorio Astrofisico di Catania (OACT), Economía Política y Hacienda Pública, Estadística Económica y Empresarial y Política Económica, Universidad de Castilla-La Mancha (UCLM), INAF - Osservatorio Astronomico di Palermo (OAPa), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), INAF - Osservatorio Astrofisico di Arcetri (OAA), M2A 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Synchrotron Radiation Facility (ESRF), Focas Research Institute, Dublin Institute of Technology, Institut national de recherche et de sécurité (Vandoeuvre lès Nancy) (INRS ( Vandoeuvre lès Nancy)), Hitotsubashi University, Department of Physiology and Pharmacology, Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]-Réseau International des Instituts Pasteur (RIIP)-Institut Pasteur, Fondation Cenci Bolognetti - Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Réseau International des Instituts Pasteur (RIIP), Universidade de Sao Paulo, Instituto Ocenografico, Department of Microbiology and Molecular Genetics, Michigan State University [East Lansing], Michigan State University System-Michigan State University System, Université libre de Bruxelles (ULB), and Newcastle University [Newcastle]

Subjects
astro-ph.SR, Stellar population, open clustersand associations: individual: Chamaeleon I, Individual: Chamaeleon I [Open clusters and associations], Open clusters and associations: Individual: Chamaeleon I, Stars: Kinematics and dynamics, Stars: Pre-main sequence, Techniques: Spectroscopic, astro-ph.GA, stars: kinematics and dynamics, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, stars: pre-main sequence, 01 natural sciences, Virial theorem, Kinematics and dynamics [Stars], Stars: Kinematics and dynamic, 0103 physical sciences, Cluster (physics), Mass segregation, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stellar evolution, QC, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QB, Physics, Pre-main sequence [Stars], open clusters and associations: individual: Chamaeleon I, 010308 nuclear & particles physics, Velocity dispersion, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], techniques: spectroscopic, Star cluster, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Spectroscopic [Techniques], Equivalent width, QB799
Abstract

Investigating the physical mechanisms driving the dynamical evolution of young star clusters is fundamental to our understanding of the star formation process and the properties of the Galactic field stars. The young (~2 Myr) and partially embedded cluster Chamaeleon I is one of the closest laboratories for the study of the early stages of star cluster dynamics in a low-density environment. The aim of this work is to study the structural and kinematical properties of this cluster combining parameters from the high-resolution spectroscopic observations of the Gaia-ESO Survey with data from the literature. Our main result is the evidence of a large discrepancy between the velocity dispersion (σ = 1.14 ± 0.35 km s) of the stellar population and the dispersion of the pre-stellar cores (~0.3 km s) derived from submillimeter observations. The origin of this discrepancy, which has been observed in other young star clusters, is not clear. It has been suggested that it may be due to either the effect of the magnetic field on the protostars and the filaments or to the dynamical evolution of stars driven by two-body interactions. Furthermore, the analysis of the kinematic properties of the stellar population puts in evidence a significant velocity shift (~1 km s) between the two subclusters located around the north and south main clouds of the cluster. This result further supports a scenario where clusters form from the evolution of multiple substructures rather than from a monolithic collapse. Using three independent spectroscopic indicators (the gravity indicator γ, the equivalent width of the Li line at 6708 Å, and the Hα 10% width), we performed a new membership selection. We found six new cluster members all located in the outer region of the cluster, proving that Chamaeleon I is probably more extended than previously thought. Starting from the positions and masses of the cluster members, we derived the level of substructure Q, the surface density Σ, and the level of mass segregation Λ of the cluster. The comparison between these structural properties and the results of N-body simulations suggests that the cluster formed in a low-density environment, in virial equilibrium or a supervirial state, and highly substructured.© 2017 ESO., This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR) in the form of the grant >Premiale VLT 2012>. This work has been partially supported by PRIN-INAF-2014. The results presented here benefited from discussions held during the Gaia-ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. M.M. acknowledges financial support from the Italian Ministry of Education, University and Research (MIUR) through grant FIRB 2012 RBFR12PM1F, from INAF through grant PRIN-2014-14, and from the MERAC Foundation. S.G.S. acknowledges the support by Fundacao para a Ciencia e Tecnologia (FCT) through national funds and a research grant (project Ref. UID/FIS/04434/2013, and PTDC/FIS-AST/7073/2014). S.G.S. also acknowledge the support from FCT through Investigador FCT contract of reference IF/00028/2014 and POPH/FSE (EC) by FEDER funding through the program Programa Operacional de Factores de Competitividade COMPETE.

Published
2017

5. The Gaia-ESO Survey: A lithium-rotation connection at 5 Myr?

Author

Delgado Mena, E., Carraro, G., Lanzafame, A., Zwitter, T., Zaggia, S., Worley, C., Vallenari, A., Sousa, S., Sbordone, L., Sacco, G., Prisinzano, L., Morbidelli, L., Monaco, L., Magrini, L., Lewis, J., Lardo, C., Koposov, S., Hourihane, A., Franciosini, E., Donati, P., Mena, E., Damiani, F., Costado, M., Casey, A., Carraro, C., Bragaglia, A., Bensby, T., Bayo, A., Gilmore, G., Flaccomio, E., Cody, A., Stauffer, J., Randich, S., Micela, G., Messina, S., Biazzo, K., Moraux, E., Frasca, A., Jeffries, R., Klutsch, A., Venuti, L., Bouvier, J., Bouvier J., Lanzafame A.C., Venuti L., Klutsch A., Jeffries R., Frasca A., Moraux E., Biazzo K., Messina S., Micela G., Randich S., Stauffer J., Cody A.M., Flaccomio E., Gilmore G., Bayo A., Bensby T., Bragaglia A., Carraro G., Casey A., Costado M.T., Damiani F., Delgado Mena E., Donati P., Franciosini E., Hourihane A., Koposov S., Lardo C., Lewis J., Magrini L., Monaco L., Morbidelli L., Prisinzano L., Sacco G., Sbordone L., Sousa S.G., Vallenari A., Worley C.C., Zaggia S., Zwitter T., Gilmore, Gerard [0000-0003-4632-0213], Casey, Andrew [0000-0003-0174-0564], Koposov, Sergey [0000-0003-2644-135X], Worley, Clare [0000-0001-9310-2898], and Apollo - University of Cambridge Repository

Subjects
stars: abundances / stars: pre-main sequence / stars: rotation / open clusters and associations: individual: NGC 2264, Stars: abundance, astro-ph.SR, stars: abundances, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rotation, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stellar evolution, Open clusters and associations: individual: NGC 2264, Stars: abundances, Stars: pre-main sequence, Stars: rotation, Astronomy and Astrophysics, Space and Planetary Science, Solar and Stellar Astrophysics (astro-ph.SR), QC, Astrophysics::Galaxy Astrophysics, QB, Physics, 010308 nuclear & particles physics, Radius, Accretion (astrophysics), Stars, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Pleiades, Equivalent width, QB799
Abstract

We investigate here the lithium content of young low-mass stars in the 5~Myr-old star forming region NGC~2264 and its relationship with rotation. We combine lithium equivalent width measurements, EW(Li), from the Gaia-ESO Survey with the determination of rotational periods from the CSI~2264 survey. We consider only bona fide non accreting cluster members in order to minimize uncertainties on EW(Li). We report the existence of a relationship between lithium content and rotation in NGC~2264 at an age of 5~Myr. The Li-rotation connection is seen over a restricted temperature range, Teff=3800--4400K, where fast rotators are Li-rich compared to slow ones. This correlation is similar to, albeit of lower amplitude than, the Li-rotation connection previously reported for K dwarfs in the 125 Myr-old Pleiades cluster. We investigate whether the non-standard pre-main sequence models developed so far to explain the Pleiades results, which are based on episodic accretion, pre-main sequence core-envelope decoupling, and/or radius inflation due to enhanced magnetic activity, can account for an early development of the Li-rotation connection. While radius inflation appears to be the most promising possibility, each of these models has issues. We therefore also discuss external causes that might operate during the first few Myr of pre-main sequence evolution, such as planet engulfment and/or steady disk accretion, as possible candidates for the common origin for Li-excess and fast rotation in young low-mass pre-main sequence stars. The emergence of a connection between lithium content and rotation rate at such an early age as 5~Myr suggests a complex link between accretion processes, early angular momentum evolution, and possibly planet formation, which likely impacts early stellar evolution and still is to be fully deciphered., Comment: 9 pages, 5 figures, Astronomy & Astrophysics, in press

Published
2016

6. The Gaia-ESO Survey: Reevaluation of the parameters of the open cluster Trumpler 20 using photometry and spectroscopy

Author

Maiorca, E., Lardo, C., Jofre, P., Hourihane, A., Worley, C., Sacco, G., Prisinzano, L., Morbidelli, L., Lewis, J., De Laverny, P., Franciosini, E., Recio-Blanco, A., Pancino, E., Korn, A., Koposov, S., Flaccomio, E., Bensby, T., Randich, S., Gilmore, G., Zaggia, S., Roman, I., Muñoz, C., Mowlavi, N., Klutsch, A., Geisler, D., Costado, M., Blanco-Cuaresma, S., Tautvaišienė, G., Sordo, R., Tosi, M., Vallenari, A., Smiljanic, R., Magrini, L., Friel, E., Bragaglia, A., Cantat-Gaudin, T., Donati, P., Jofré, P., M2A 2014, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Department of Astronomy and Space Physics [Uppsala], Uppsala University, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Donati P., Cantat Gaudin T., Bragaglia A., Friel E., Magrini L., Smiljanic R., Vallenari A., Tosi M., Sordo R., Tautvaisiene G., Blanco-Cuaresma S., Costado M.T., Geisler D., Klutsch A., Mowlavi N., Munoz C., San Roman I., Zaggia S., Gilmore G., Randich S., Bensby T., Flaccomio E., Koposov S.E., Korn A.J., Pancino E., Recio-Blanco A., Franciosini E., De Laverny P., Lewis J., Morbidelli L., Prisinzano L., Sacco G., Worley C.C., Hourihane A., Jofre P., Lardo C., and Maiorca E.

Subjects
Physics, Line-of-sight, Spiral galaxy, astro-ph.SR, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Metallicity, FOS: Physical sciences, Astronomy and Astrophysics, Open clusters and associations: general, Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Photometry (optics), Stars, Distance modulus, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Hertzsprung-Russell and C-M diagram, 10. No inequality, Red clump, Solar and Stellar Astrophysics (astro-ph.SR), Open cluster
Abstract

Trumpler 20 is an old open cluster (OC) located toward the Galactic centre, at about 3 kpc from the Sun and $\sim$7 kpc from the Galactic centre. Its position makes this cluster particularly interesting in the framework of the chemical properties of the Galactic disc because very few old OCs reside in the inner part of the disc. For this reason it has been selected as a cluster target of the Gaia-ESO Survey, and spectra of many stars in the main sequence and red clump phases are now available. Moreover, although it has been studied by several authors in the past, no consensus on the evolutionary status of Tr 20 has been reached. The heavy contamination of field stars (the line of sight of Tr 20 crosses the Carina spiral arm) complicates a correct interpretation. Another interesting aspect of the cluster is that it shows a broadened main-sequence turn-off and a prominent and extended red-clump, characteristics that are not easily explained by classical evolutionary models. Exploiting both spectroscopic information from the Gaia-ESO Survey (and the ESO archive) and literature photometry, we obtain a detailed and accurate analysis of the properties of the cluster. We make use of the first accurate metallicity measurement ever obtained from several spectra of red clump stars, and of cluster membership determination using radial velocities. According to the evolutionary models adopted, we find that Tr 20 has an age in the range 1.35-1.66 Gyr, an average reddening $E(B-V)$ in the range 0.31-0.35 mag, and a distance modulus $(m-M)_0$ between 12.64 and 12.72 mag. The spectroscopic metallicity is [Fe/H]=+0.17 dex. We discuss the structural properties of the object and constrain possible hypotheses for its broadened upper main sequence by estimating the effect of differential reddening and its extended red clump., 14 pages, 14 figures - Accepted on 9 Dec. 2013 Reference list updated and minor corrections added to the text

Published
2014

7. The AMBRE project: Results from the MATISSE analysis of the ESO-FEROS archived spectra.

Author

Worley, C. C., de Laverny, P., Recio-Blanco, A., Hill, V., and Kordopatis, G.

Subjects
*STELLAR activity, *RADIAL velocity of galaxies, *RADIAL velocity of stars, *SPECTROGRAPHS, *ASTROPHYSICS
Abstract

The goal of AMBRE, a joint project between ESO and the Observatoire de la Cote d'Azur, is to provide a homogeneous determination of the stellar parameters (including mean metallicity and some chemical abundances) for the archived spectra of the FEROS, HARPS, UVES and Flames/GIRAFFE spectrographs. We present here a preliminary analysis of the FEROS stellar sample. The stellar parameters, derived using the stellar classification algorithm MATISSE, have been combined with distances and radial velocities in order to explore current theories regarding galactic stellar populations. We have reviewed the sample for potential disk stars with which we can explore kinematic and chemical signatures of the thin and thick disk. We present here a comparison of the potential disk stellar sample to the analysis of 66 disk stars that was carried out in. [ABSTRACT FROM AUTHOR]

Published
2012
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8. The AMBRE Project: Constraining the lithium evolution in the Milky Way

Author

Prantzos, N., Masseron, T., De Pascale, M., Worley, C., Recio-Blanco, A., De Laverny, P., Guiglion, G., Mikolaitis, Š., Mikolaitis, S., ITA, GBR, and FRA

Subjects
010504 meteorology & atmospheric sciences, Milky Way, Metallicity, chemistry.chemical_element, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Abundance (ecology), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Physics::Atomic Physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Stars, chemistry, Space and Planetary Science, Homogeneous, Astrophysics of Galaxies (astro-ph.GA), Lithium, Astrophysics::Earth and Planetary Astrophysics
Abstract

The chemical evolution of lithium in the Milky Way represents a major problem in modern astrophysics. Indeed, lithium is, on the one hand, easily destroyed in stellar interiors, and, on the other hand, produced at some specific stellar evolutionary stages that are still not well constrained. The goal of this paper is to investigate the lithium stellar content of Milky Way stars in order to put constraints on the lithium chemical enrichment in our Galaxy, in particular in both the thin and thick discs. Thanks to high-resolution spectra from the ESO archive and high quality atmospheric parameters, we were able to build a massive and homogeneous catalogue of lithium abundances for 7300 stars derived with an automatic method coupling, a synthetic spectra grid, and a Gauss-Newton algorithm. We validated these lithium abundances with literature values, including those of the Gaia benchmark stars. In terms of lithium galactic evolution, we show that the interstellar lithium abundance increases with metallicity by 1 dex from [M/H]=-1 dex to +0.0 dex. Moreover, we find that this lithium ISM abundance decreases by about 0.5 dex at super-solar metalllicity. Based on a chemical separation, we also observed that the stellar lithium content in the thick disc increases rather slightly with metallicity, while the thin disc shows a steeper increase. The lithium abundance distribution of alpha-rich, metal-rich stars has a peak at A(Li)~3 dex. We conclude that the thick disc stars suffered of a low lithium chemical enrichment, showing lithium abundances rather close to the Spite plateau while the thin disc stars clearly show an increasing lithium chemical enrichment with the metallicity, probably thanks to the contribution of low-mass stars., Comment: 15 pages, 12 figures, 2 tables

9. The AMBRE Project: Stellar parameterisation of the ESO:FEROS archived spectra.

Author

Worley, C. C., de Laverny, P., Recio-Blanco, A., Hill, V., Bijaoui, A., and Ordenovic, C.

Subjects
*TEMPERATURE of stars, *SPECTROGRAPHS, *COSMIC abundances, *PARAMETERIZATION, *ASTROPHYSICS
Abstract

Context. The AMBRE Project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Côte d'Azur (OCA) that has been established in order to carry out the determination of stellar atmospheric parameters for the archived spectra of four ESO spectrographs. Aims. The analysis of the FEROS archived spectra for their stellar parameters (effective temperatures, surface gravities, global metallicities, alpha element to iron ratios and radial velocities) has been completed in the first phase of the AMBRE Project. From the complete ESO:FEROS archive dataset that was received, a total of 21?551 scientific spectra have been identified, covering the period 2005 to 2010. These spectra correspond to 6285 stars. Methods. The determination of the stellar parameters was carried out using the stellar parameterisation algorithm, MATISSE (MATrix Inversion for Spectral SynthEsis), which has been developed at OCA to be used in the analysis of large scale spectroscopic studies in galactic archaeology. An analysis pipeline has been constructed that integrates spectral normalisation, cleaning and radial velocity correction procedures in order that the FEROS spectra could be analysed automatically with MATISSE to obtain the stellar parameters. The synthetic grid against which the MATISSE analysis is carried out is currently constrained to parameters of FGKM stars only. Results. Stellar atmospheric parameters, effective temperature, surface gravity, metallicity and alpha element abundances, were determined for 6508 (30.2%) of the FEROS archived spectra (∼3087 stars). Radial velocities were determined for 11?963 (56%) of the archived spectra. 2370 (11%) spectra could not be analysed within the pipeline due to very low signal-to-noise ratios or missing spectral orders. 12?673 spectra (58.8%) were analysed in the pipeline but their parameters were discarded based on quality criteria and error analysis determined within the automated process. The majority of these rejected spectra were found to have broad spectral features, as probed both by the direct measurement of the features and cross-correlation function breadths, indicating that they may be hot and/or fast rotating stars, which are not considered within the adopted reference synthetic spectra grid. The current configuration of the synthetic spectra grid is devoted to slow-rotating FGKM stars. Hence non-standard spectra (binaries, chemically peculiar stars etc.) that could not be identified may pollute the analysis. [ABSTRACT FROM AUTHOR]

Published
2012
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10. Gaia-ESO Survey: Gas dynamics in the Carina nebula through optical emission lines

Author

Rosaria Bonito, Lorenzo Monaco, C. C. Worley, V. M. Kalari, Giovanni Carraro, A. Hourihane, G. G. Sacco, A. C. Lanzafame, Jack Lewis, Sofia Randich, Elena Pancino, Ricardo Dorda, L. Prisinzano, Sergey E. Koposov, Michela Mapelli, Tomaž Zwitter, M. T. Costado, Emilio J. Alfaro, Ettore Flaccomio, J. Maíz Apellániz, A. Klutsch, Carmela Lardo, F. Damiani, L. Morbidelli, Simone Zaggia, Giuseppina Micela, Amelia Bayo, Gerard Gilmore, Laura Magrini, Andrew R. Casey, E. Franciosini, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Astrofísica Estelar (AE), Damiani, F., Bonito, R., Magrini, L., Prisinzano, L., Mapelli, M., Micela, G., Kalari, V., Maíz Apellániz, J., Gilmore, G., Randich, S., Alfaro, E., Flaccomio, E., Koposov, S., Klutsch, A., Lanzafame, A., Pancino, E., Sacco, G., Bayo, A., Carraro, G., Casey, A., Costado, M., Franciosini, E., Hourihane, A., Lardo, C., Lewis, J., Monaco, L., Morbidelli, L., Worley, C., Zaggia, S., Zwitter, T., Dorda, R., Damiani F., Bonito R., Magrini L., Prisinzano L., Mapelli M., Micela G., Kalari V., Maiz Apellaniz J., Gilmore G., Randich S., Alfaro E., Flaccomio E., Koposov S., Klutsch A., Lanzafame A.C., Pancino E., Sacco G.G., Bayo A., Carraro G., Casey A.R., Costado M.T., Franciosini E., Hourihane A., Lardo C., Lewis J., Monaco L., Morbidelli L., Worley C., Zaggia S., Zwitter T., Dorda R., European Research Council, Gilmore, Gerard [0000-0003-4632-0213], Koposov, Sergey [0000-0003-2644-135X], Casey, Andrew [0000-0003-0174-0564], Worley, Clare [0000-0001-9310-2898], and Apollo - University of Cambridge Repository

Subjects
HII regions, astro-ph.SR, astro-ph.GA, Astrophysics::High Energy Astrophysical Phenomena, Shell (structure), Flux, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, ISM: individual objects: Carina nebula, ISM: general, Ionization, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, HII region, Emission spectrum, 010303 astronomy & astrophysics, QC, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QB, Astronomía y Astrofísica, Physics, Nebula, general [ISM], 010308 nuclear & particles physics, individual objects: Carina nebula [ISM], Astronomy and Astrophysics, Gas dynamics, Astronomy and Astrophysic, Astrophysics - Astrophysics of Galaxies, Dust lane, Core (optical fiber), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract

Aims. We present observations from the Gaia-ESO Survey in the lines of Hα, [N II], [S II], and He I of nebular emission in the central part of the Carina nebula. Methods. We investigate the properties of the two already known kinematic components (approaching and receding), which account for the bulk of emission. Moreover, we investigate the features of the much less known low-intensity high-velocity (absolute RV >50 km s) gas emission. Results. We show that gas giving rise to Hα and He I emission is dynamically well correlated with but not identical to gas seen through forbidden-line emission. Gas temperatures are derived from line-width ratios, and densities from [S II] doublet ratios. The spatial variation of N ionization is also studied, and found to differ between the approaching and receding components. The main result is that the bulk of the emission lines in the central part of Carina arise from several distinct shell-like expanding regions, the most evident found around η Car, the Trumpler 14 core, and the star WR25. These >shells> are non-spherical and show distortions probably caused by collisions with other shells or colder, higher-density gas. Some of them are also partially obscured by foreground dust lanes, while very little dust is found in their interior. Preferential directions, parallel to the dark dust lanes, are found in the shell geometries and physical properties, probably related to strong density gradients in the studied region. We also find evidence that the ionizing flux emerging from η Car and the surrounding Homunculus nebula varies with polar angle. The high-velocity components in the wings of Hα are found to arise from expanding dust reflecting the η Car spectrum. © ESO, 2016., This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541

Published
2016

11. The Gaia-ESO survey: galactic evolution of lithium from iDR6

Author

Grazina Tautvaisiene, Guillaume Guiglion, Andreas Korn, V. Grisoni, P. Bonifacio, Rodolfo Smiljanic, G. Casali, E. Franciosini, Donatella Romano, Paula Jofre, P. de Laverny, R. D. Jeffries, Thomas Bensby, Alessio Mucciarelli, Francesco Damiani, E. Pancino, S. L. Martell, D. Montes, Sofia Randich, Antonella Vallenari, Lorenzo Spina, Cristina Chiappini, Maria Bergemann, A. Bragaglia, F. M. Jiménez-Esteban, M. L. Gutiérrez Albarrán, M. Bellazzini, X. Fu, G. Carraro, Laura Magrini, F. Matteucci, Paolo Ventura, Anais Gonneau, C. C. Worley, Romano D., Magrini L., Randich S., Casali G., Bonifacio P., Jeffries R.D., Matteucci F., Franciosini E., Spina L., Guiglion G., Chiappini C., Mucciarelli A., Ventura P., Grisoni V., Bellazzini M., Bensby T., Bragaglia A., De Laverny P., Korn A.J., Martell S.L., Tautvaisiene G., Carraro G., Gonneau A., Jofre P., Pancino E., Smiljanic R., Vallenari A., Fu X., Gutierrez Albarran M.L., Jimenez-Esteban F.M., Montes D., Damiani F., Bergemann M., Worley C., Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrofísica, Metallicity, FOS: Physical sciences, chemistry.chemical_element, Astrophysics, 7. Clean energy, 01 natural sciences, evolution [Galaxy], Astronomi, astrofysik och kosmologi, Abundance (ecology), 0103 physical sciences, stellar content [Galaxy], Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, nuclear reactions, Physics, Galaxy: evolution, Galaxy: stellar content, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, abundances, Stars: abundances, White dwarf, abundances [Galaxy], nucleosynthesis, Astronomy and Astrophysics, Open clusters and associations: general, Astrophysics - Astrophysics of Galaxies, abundances [stars], Galaxy: abundance, Astronomía, Stars, Supernova, Meteorite, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Lithium, general [open clusters and associations], Nuclear reactions, nucleosynthesis, abundance, Open cluster
Abstract

We exploit the unique characteristics of a sample of open clusters (OCs) and field stars for which high-precision 7Li abundances and stellar parameters are homogeneously derived by the Gaia-ESO Survey (GES). We derive possibly undepleted 7Li abundances for 26 OCs and star forming regions with ages from young to old spanning a large range of Galactocentric distances, which allows us to reconstruct the local late Galactic evolution of lithium as well as its current abundance gradient along the disc. Field stars are added to look further back in time and to constrain 7Li evolution in other Galactic components. The data are then compared to theoretical tracks from chemical evolution models that implement different 7Li forges. We find that the upper envelope of the 7Li abundances measured in field stars of nearly solar metallicities traces very well the level of lithium enrichment attained by the ISM as inferred from observations of cluster stars. We confirm previous findings that the abundance of 7Li in the solar neighbourhood does not decrease at supersolar metallicity. The comparison of the data with the chemical evolution model predictions favours a scenario in which the majority of the 7Li abundance in meteorites comes from novae. Current data also seem to suggest that the nova rate flattens out at later times. This requirement might have implications for the masses of the white dwarf nova progenitors and deserves further investigation. Neutrino-induced reactions taking place in core-collapse supernovae also produce some fresh lithium. This likely makes a negligible contribution to the meteoritic abundance, but could be responsible for a mild increase of the 7Li abundance in the ISM of low-metallicity systems that would counterbalance the astration processes., 17 pages, 10 figures, 3 tables (full tables 1 and 3 only available at the CDS), accepted for publication in Astronomy and Astrophysics. Version 2 includes corrections from language editor

Published
2021

12. Atomic data for the Gaia-ESO Survey

Author

Martin Asplund, Nils Ryde, Paul S. Barklem, Andrew R. Casey, Bengt Edvardsson, Henrik Jönsson, A. C. Lanzafame, Andreas Korn, Šarūnas Mikolaitis, L. Morbidelli, Gerard Gilmore, Maria Bergemann, E. Pancino, Lorenzo Monaco, Ulrike Heiter, Francesco Damiani, P. de Laverny, Clare Worley, Laura Magrini, Carmela Lardo, Paula Jofre, Sofia Feltzing, Simone Zaggia, Thomas Bensby, A. Bayo Aran, Rodolfo Smiljanic, Sofia Randich, Karin Lind, Juliet C. Pickering, Thomas Masseron, Worley, Clare [0000-0001-9310-2898], Gilmore, Gerard [0000-0003-4632-0213], Apollo - University of Cambridge Repository, Heiter U., Lind K., Bergemann M., Asplund M., Mikolaitis S., Barklem P.S., Masseron T., De Laverny P., Magrini L., Edvardsson B., Jonsson H., Pickering J.C., Ryde N., Bayo Aran A., Bensby T., Casey A.R., Feltzing S., Jofre P., Korn A.J., Pancino E., Damiani F., Lanzafame A., Lardo C., Monaco L., Morbidelli L., Smiljanic R., Worley C., Zaggia S., Randich S., and Gilmore G.F.

Subjects
010504 meteorology & atmospheric sciences, stars: abundances, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Astronomical spectroscopy, Spectral line, Astronomi, astrofysik och kosmologi, surveys, 0103 physical sciences, Arcturus, Radiative transfer, atomic data, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, Hyperfine structure, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Line (formation), Physics, stars: late-type, Astronomy and Astrophysics, abundances [stars], Stars: Abundance, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, late-type [stars], Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We describe the atomic and molecular data that were used for the abundance analyses of FGK-type stars carried out within the Gaia-ESO Survey. We present an unprecedented effort to create a homogeneous line list, which was used by several abundance analysis groups to calculate synthetic spectra and equivalent widths. The atomic data are accompanied by quality indicators and detailed references to the sources. The atomic and molecular data are made publicly available in electronic form. In general experimental transition probabilities were preferred but theoretical values were also used. Astrophysical gf-values were avoided due to the model-dependence of such a procedure. For elements whose lines are significantly affected by hyperfine structure or isotopic splitting a concerted effort has been made to collate the necessary data for the individual line components. We also performed a detailed investigation of available data for line broadening due to collisions with neutral hydrogen atoms. Synthetic spectra calculated for the Sun and Arcturus were used to assess the blending properties of the lines. Among a subset of over 1300 lines of 35 elements in the wavelength ranges from 475 nm to 685 nm and from 850 nm to 895 nm we identified about 200 lines of 24 species which have accurate gf-values and are free of blends in the spectra of the Sun and Arcturus. For the broadening due to collisions with neutral hydrogen we recommend data based on Anstee-Barklem-O'Mara theory, where available, and to avoid lines of neutral species otherwise. Theoretical broadening data by R.L. Kurucz should be used for Sc II, Ti II, and Y II lines. For ionised rare-earth species the Uns\"old approximation with an enhancement factor of 1.5 for the line width can be used. Desirable improvements in atomic data were identified for a number of species, including Al I, S I, Cr II, Na I, Si I, Ca II, and Ni I., Comment: Accepted for publication in section 12. Atomic, molecular, and nuclear data of Astronomy and Astrophysics; main part 25 pages, 8 tables, 5 figures; appendices 53 pages, 23 tables, 29 figures

Published
2021
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13. Gaia-ESO Survey::INTRIGOSS - A new library of High Resolution Synthetic Spectra

Author

Gerry Gilmore, A. Hourihane, E. Franciosini, Clare Worley, Ettore Flaccomio, L. Morbidelli, Amelia Bayo, G. G. Sacco, James R. Lewis, Andrew R. Casey, Miguel Chavez, Carmela Lardo, Sergey E. Koposov, Paolo Di Marcantonio, Giovanni Carraro, Andreas J. Korn, Sofia Randich, Laura Magrini, Tomaz Zwitter, Paula Jofre, Carlo Morossi, Mariagrazia Franchini, Franchini, M [0000-0001-5611-2333], Flaccomio, E [0000-0002-3638-5788], Koposov, SE [0000-0003-2644-135X], Bayo, A [0000-0001-7868-7031], Carraro, G [0000-0002-0155-9434], Casey, A [0000-0003-0174-0564], Lardo, C [0000-0002-4295-8773], Zwitter, T [0000-0002-2325-8763], Apollo - University of Cambridge Repository, ITA, USA, GBR, AUS, CHL, MEX, SVN, SWE, CHE, Franchini M., Morossi C., Di Marcantonio P., Chavez M., Gilmore G., Randich S., Flaccomio E., Koposov S.E., Korn A.J., Bayo A., Carraro G., Casey A., Franciosini E., Hourihane A., Jofre P., Lardo C., Lewis J., Magrini L., Morbidelli L., Sacco G.G., Worley C., and Zwitter T.

Subjects
astro-ph.SR, FOS: Physical sciences, Flux, Blanketing, Astrophysics::Cosmology and Extragalactic Astrophysics, astronomical databases: miscellaneous, Astrophysics, 7. Clean energy, 01 natural sciences, Spectral line, Atmosphere, Astronomi, astrofysik och kosmologi, Consistency (statistics), 0103 physical sciences, Astronomy, Astrophysics and Cosmology, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, stars: late-type, Resolution (electron density), Astronomy and Astrophysics, astronomical databases: miscellaneou, miscellaneous [astronomical databases], Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Spectral energy distribution, late-type [stars], Astrophysics::Earth and Planetary Astrophysics
Abstract

We present a high resolution synthetic spectral library, INTRIGOSS, designed for studying FGK stars. The library is based on atmosphere models computed with specified individual element abundances via ATLAS12 code. Normalized SPectra (NSP) and surface Flux SPectra (FSP), in the 4830-5400 A, wavelength range, were computed with the SPECTRUM code. INTRIGOSS uses the solar composition by Grevesse et al. 2007 and four [alpha/Fe] abundance ratios and consists of 15,232 spectra. The synthetic spectra are computed with astrophysical gf-values derived by comparing synthetic predictions with a very high SNR solar spectrum and the UVES-U580 spectra of five cool giants. The validity of the NSPs is assessed by using the UVES-U580 spectra of 2212 stars observed in the framework of the Gaia-ESO Survey and characterized by homogeneous and accurate atmospheric parameter values and by detailed chemical compositions. The greater accuracy of NSPs with respect to spectra from the AMBRE, GES_Grid, PHOENIX, C14, and B17 synthetic spectral libraries is demonstrated by evaluating the consistency of the predictions of the different libraries for the UVES-U580 sample stars. The validity of the FSPs is checked by comparing their prediction with both observed spectral energy distribution and spectral indices. The comparison of FSPs with SEDs derived from ELODIE, INDO--U.S., and MILES libraries indicates that the former reproduce the observed flux distributions within a few percent and without any systematic trend. The good agreement between observational and synthetic Lick/SDSS indices shows that the predicted blanketing of FSPs well reproduces the observed one, thus confirming the reliability of INTRIGOSS FSPs., 32 pages, 12 figures

Published
2018

14. The AMBRE Project: chemical evolution models for the Milky Way thick and thin discs

Author

Alejandra Recio-Blanco, Francesca Matteucci, E. Spitoni, V. Grisoni, Ŝ. Mikolaitis, C. C. Worley, P. de Laverny, Michael R. Hayden, Grisoni, V., Spitoni, E., Matteucci, F., Recio-Blanco, A., de Laverny, P., Hayden, M., Mikolaitis, Ŝ., and Worley, C. C.

Subjects
Metallicity, Milky Way, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, evolution [Galaxy], 0103 physical sciences, Galaxy formation and evolution, Astrophysics::Solar and Stellar Astrophysics, abundance [Galaxy], 010303 astronomy & astrophysics, Galaxy: abundances, Galaxy: evolution, Galaxy: formation, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Star formation, Astronomy, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Galaxy, Stars, Distribution function, formation [Galaxy], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract

We study the chemical evolution of the thick and thin discs of the Galaxy by comparing detailed chemical evolution models with recent data from the AMBRE Project. The data suggest that the stars in the thick and thin discs form two distinct sequences with the thick disc stars showing higher [{\alpha}/Fe] ratios. We adopt two different approaches to model the evolution of thick and thin discs. In particular, we adopt: i) a two-infall approach where the thick disc forms fast and before the thin disc and by means of a fast gas accretion episode, whereas the thin disc forms by means of a second accretion episode on a longer timescale; ii) a parallel approach, where the two discs form in parallel but at different rates. By comparing our model results with the observed [Mg/Fe] vs. [Fe/H] and the metallicity distribution functions in the two Galactic components, we conclude that the parallel approach can account for a group of {\alpha}-enhanced metal rich stars present in the data, whereas the two-infall approach cannot explain these stars unless they are the result of stellar migration. In both approaches, the thick disc has formed on a timescale of accretion of 0.1 Gyr, whereas the thin disc formed on a timescale of 7 Gyr in the solar region. In the two-infall approach a gap in star formation between the thick and thin disc formation of several hundreds of Myr should be present, at variance with the parallel approach where no gap is present., Comment: 12 pages, 10 figures. Accepted for publication in MNRAS

Published
2017

15. The Gaia-ESO Survey: Exploring the complex nature and origins of the Galactic bulge populations

Author

Mathias Schultheis, Dante Minniti, A. Hourihane, Manuela Zoccali, Amelia Bayo, Francesco Damiani, Giovanni Carraro, C. C. Worley, Elena Pancino, Alejandra Recio-Blanco, Francesca Matteucci, Andrew R. Casey, Paula Jofre, G. G. Sacco, Thomas Bensby, Sergey E. Koposov, S. Mikolaitis, M. T. Costado, Carmela Lardo, L. Morbidelli, Paolo Donati, Vanessa Hill, Michael R. Hayden, Sofia Feltzing, P. de Laverny, Ettore Flaccomio, E. Spitoni, C. Babusiaux, Laura Magrini, Sofia Randich, Karin Lind, Jack Lewis, Gerard Gilmore, Emilio J. Alfaro, E. Franciosini, Oscar A. Gonzalez, Simone Zaggia, Angela Bragaglia, A. Rojas-Arriagada, Millennium Institute of Astrophysics, Instituto de Astrofisica [Santiago], Pontificia Universidad Católica de Chile (UC), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), University of Turin, Groupe d'études pour l'application des méthodes scientifiques à l'architecture et à l'urbanisme (GAMSAU), École nationale supérieure d'architecture de Marseille-Luminy (ENSA-M), Cognition Behaviour Technology (CobTek), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre Hospitalier Universitaire de Nice (CHU Nice)-Institut Claude Pompidou [Nice] (ICP - Nice)-Université Côte d'Azur (UCA), European Commission, European Research Council, Leverhulme Trust, Centre National de la Recherche Scientifique (France), Agence Nationale de la Recherche (France), Comisión Nacional de Investigación Científica y Tecnológica (Chile), Rojas Arriagada, A., Recio Blanco, A., De Laverny, P., Mikolaitis, Š., Matteucci, MARIA FRANCESCA, Spitoni, Emanuele, Schultheis, M., Hayden, M., Hill, V., Zoccali, M., Minniti, D., Gonzalez, O. A., Gilmore, G., Randich, S., Feltzing, S., Alfaro, E. J., Babusiaux, C., Bensby, T., Bragaglia, A., Flaccomio, E., Koposov, S. E., Pancino, E., Bayo, A., Carraro, G., Casey, A. R., Costado, M. T., Damiani, F., Donati, P., Franciosini, E., Hourihane, A., Jofré, P., Lardo, C., Lewis, J., Lind, K., Magrini, L., Morbidelli, L., Sacco, G. G., Worley, C. C., Zaggia, S., Rojas-Arriagada A., Recio-Blanco A., De Laverny P., Mikolaitis S., Matteucci F., Spitoni E., Schultheis M., Hayden M., Hill V., Zoccali M., Minniti D., Gonzalez O.A., Gilmore G., Randich S., Feltzing S., Alfaro E.J., Babusiaux C., Bensby T., Bragaglia A., Flaccomio E., Koposov S.E., Pancino E., Bayo A., Carraro G., Casey A.R., Costado M.T., Damiani F., Donati P., Franciosini E., Hourihane A., Jofre P., Lardo C., Lewis J., Lind K., Magrini L., Morbidelli L., Sacco G.G., Worley C.C., Zaggia S., COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre Hospitalier Universitaire de Nice (CHU Nice)-Institut Claude Pompidou [Nice] (ICP - Nice)

Subjects
stars: abundances, Galaxy: bulge, Galaxy: formation, Galaxy: abundances, Galaxy: stellar content, astro-ph.GA, bulge [Galaxy], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Bulge, 0103 physical sciences, Thick disk, stellar content [Galaxy], Astrophysics::Solar and Stellar Astrophysics, abundance [Galaxy], 010303 astronomy & astrophysics, Red clump, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Star formation, Plane (geometry), abundances [Galaxy], Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Bimodality, Galaxy: abundance, Stars, Thin disk, formation [Galaxy], Space and Planetary Science, abundances [Stars], Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Full list of authors: Rojas-Arriagada, A.; Recio-Blanco, A.; de Laverny, P.; Mikolaitis, Š.; Matteucci, F.; Spitoni, E.; Schultheis, M.; Hayden, M.; Hill, V.; Zoccali, M.; Minniti, D.; Gonzalez, O. A.; Gilmore, G.; Randich, S.; Feltzing, S.; Alfaro, E. J.; Babusiaux, C.; Bensby, T.; Bragaglia, A.; Flaccomio, E. Koposov, S. E.; Pancino, E.; Bayo, A.; Carraro, G.; Casey, A. R.; Costado, M. T.; Damiani, F.; Donati, P.; Franciosini, E.; Hourihane, A.; Jofré, P.; Lardo, C.; Lewis, J.; Lind, K.; Magrini, L.; Morbidelli, L.; Sacco, G. G.; Worley, C. C.; Zaggia, S., Context. As observational evidence steadily accumulates, the nature of the Galactic bulge has proven to be rather complex: the structural, kinematic, and chemical analyses often lead to contradictory conclusions. The nature of the metal-rich bulge - and especially of the metal-poor bulge - and their relation with other Galactic components, still need to be firmly defined on the basis of statistically significant high-quality data samples. Aims. We used the fourth internal data release of the Gaia-ESO survey to characterize the bulge metallicity distribution function (MDF), magnesium abundance, spatial distribution, and correlation of these properties with kinematics. Moreover, the homogeneous sampling of the different Galactic populations provided by the Gaia-ESO survey allowed us to perform a comparison between the bulge, thin disk, and thick disk sequences in the [Mg/Fe] vs. [Fe/H] plane in order to constrain the extent of their eventual chemical similarities. Methods. We obtained spectroscopic data for ∼2500 red clump stars in 11 bulge fields, sampling the area -10° ≥ l ≥ +8° and -10° ≥ b ≥ -4° from the fourth internal data release of the Gaia-ESO survey. A sample of ∼6300 disk stars was also selected for comparison. Spectrophotometric distances computed via isochrone fitting allowed us to define a sample of stars likely located in the bulge region. Results. From a Gaussian mixture models (GMM) analysis, the bulge MDF is confirmed to be bimodal across the whole sampled area. The relative ratio between the two modes of the MDF changes as a function of b, with metal-poor stars dominating at high latitudes. The metal-rich stars exhibit bar-like kinematics and display a bimodality in their magnitude distribution, a feature which is tightly associated with the X-shape bulge. They overlap with the metal-rich end of the thin disk sequence in the [Mg/Fe] vs. [Fe/H] plane. On the other hand, metal-poor bulge stars have a more isotropic hot kinematics and do not participate in the X-shape bulge. Their Mg enhancement level and general shape in the [Mg/Fe] vs. [Fe/H] plane is comparable to that of the thick disk sequence. The position at which [Mg/Fe] starts to decrease with [Fe/H], called the "knee", is observed in the metal-poor bulge at [Fe/H] = -0:37 ± 0:09, being 0.06 dex higher than that of the thick disk. Although this difference is inside the error bars, it suggest a higher star formation rate (SFR) for the bulge than for the thick disk. We estimate an upper limit for this difference of Δ[Fe/H] = 0:24 dex. Finally, we present a chemical evolution model that suitably fits the whole bulge sequence by assuming a fast (, This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and the Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR) in the form of the grant "Premiale VLT 2012". The results presented here benefited from discussions held during the Gaia-ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. A. Recio-Blanco, P. de Laverny, and V. Hill acknowledge the Programme National de Cosmologie et Galaxies (PNCG) of CNRS/INSU, France, for financial support. A. Recio-Blanco, P. de Laverny, and V. Hill acknowledge financial support form the ANR 14-CE33-014-01. M. Zoccali gratefully acknowledges support from the Ministry of Economy, Development, and Tourism's Millenium Science Initiative through grant IC120009, awarded to the Millenium Institute of Astrophysics (MAS), by Fondecyt Regular 1150345 and by the BASAL-CATA Center for Astrophysics and Associated Technologies PFB-06.

Published
2017

16. The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars

Author

Thomas Nordlander, R. Sordo, C. Babusiaux, D. Montes, P. Gruyters, Ettore Flaccomio, Laura Magrini, C. Muñoz, Sergey E. Koposov, C. Allende Prieto, Eileen D. Friel, Giovanni Carraro, K. Biazzo, S. Duffau, Thomas Masseron, G. G. Sacco, Martin Asplund, Carmela Lardo, Luca Sbordone, M. T. Costado, Ignacio Negueruela, Annette M. N. Ferguson, S. Blanco-Cuaresma, Amelia Bayo, Ch. Martayan, I. San Roman, Lorenzo Monaco, Nuno C. Santos, L. Morbidelli, Ulrike Heiter, Enrico Maiorca, Sofia Feltzing, H. W. Rix, Janet E. Drew, Caroline Soubiran, Guillaume Guiglion, Gregory R. Ruchti, Antonella Vallenari, S. Van Eck, Vanessa Hill, P. Donati, S. G. Sousa, Rodolfo Smiljanic, Heather R. Jacobson, Marc Weber, James Binney, Giuseppina Micela, Bengt Edvardsson, R. D. Jeffries, Marica Valentini, Angela Bragaglia, Thierry Morel, Y. Chorniy, Michael G. Irwin, G. Barisevičius, A. C. Lanzafame, L. Prisinzano, Jack Lewis, E. Delgado-Mena, Lorenzo Spina, Hans-Günter Ludwig, Simone Zaggia, P. Francois, S. Villanova, Nils Ryde, N. A. Walton, E. Puzeras, R. J. Jackson, Elena Pancino, J. I. González Hernández, Piercarlo Bonifacio, Šarūnas Mikolaitis, Gerard Gilmore, Thomas Bensby, Alessio Mucciarelli, Douglas Geisler, Paula Jofre, T. Prusti, Sofia Randich, Matthias Steffen, Karin Lind, P. de Laverny, Gianni Marconi, Clare Worley, R. Blomme, Camilla Juul Hansen, Emilio J. Alfaro, E. Franciosini, Tristan Cantat-Gaudin, Alejandra Recio-Blanco, Henrik Jönsson, V. Zh. Adibekyan, Grazina Tautvaisiene, Hugo M. Tabernero, Andreas Korn, Elisabetta Caffau, Francesco Damiani, A. Hourihane, Aldo Serenelli, Maria Bergemann, Antonio Frasca, L. Pasquini, Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Astrofísica Estelar (AE), Smiljanic, R., Korn, A. J., Bergemann, M., Frasca, A., Magrini, L., Masseron, T., Pancino, E., Ruchti, G., San Roman, I., Sbordone, L., Sousa, S. G., Tabernero, H., Tautvaišienė, G., Valentini, M., Weber, M., Worley, C. C., Adibekyan, V. Zh., Allende Prieto, C., Barisevičius, G., Biazzo, K., Blanco-Cuaresma, S., Bonifacio, P., Bragaglia, A., Caffau, E., Cantat-Gaudin, T., Chorniy, Y., de Laverny, P., Delgado-Mena, E., Donati, P., Duffau, S., Franciosini, E., Friel, E., Geisler, D., González Hernández, J. I., Gruyters, P., Guiglion, G., Hansen, C. J., Heiter, U., Hill, V., Jacobson, H. R., Jofre, P., Jönsson, H., Lanzafame, A. C., Lardo, C., Ludwig, H.-G., Maiorca, E., Mikolaitis, Š., Montes, D., Morel, T., Mucciarelli, A., Muñoz, C., Nordlander, T., Pasquini, L., Puzeras, E., Recio-Blanco, A., Ryde, N., Sacco, G., Santos, N. C., Serenelli, A. M., Sordo, R., Soubiran, C., Spina, L., Steffen, M., Vallenari, A., Van Eck, S., Villanova, S., Gilmore, G., Randich, S., Asplund, M., Binney, J., Drew, J., Feltzing, S., Ferguson, A., Jeffries, R., Micela, G., Negueruela, I., Prusti, T., Rix, H.-W., Alfaro, E., Babusiaux, C., Bensby, T., Blomme, R., Flaccomio, E., François, P., Irwin, M., Koposov, S., Walton, N., Bayo, A., Carraro, G., Costado, M. T., Damiani, F., Edvardsson, B., Hourihane, A., Jackson, R., Lewis, J., Lind, K., Marconi, G., Martayan, C., Monaco, L., Morbidelli, L., Prisinzano, L., Zaggia, S., Department of Astronomy and Space Physics [Uppsala], Uppsala University, M2A 2014, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Lund Observatory, Lund University [Lund], INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), Université de Liège, Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto, Departamento de Física e Astronomia [Porto] (DFA/FCUP), Faculdade de Ciências da Universidade do Porto (FCUP), Universidade do Porto-Universidade do Porto, Laboratoire des Agrégats Moléculaires et Matériaux Inorganiques (LAMMI), Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2), Institut d'Astronomie et d'Astrophysique, Université libre de Bruxelles (ULB), INAF - Osservatorio Astronomico di Palermo (OAPa), Agence Spatiale Européenne (ESA), European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), European Southern Observatory (ESO), Naval Postgraduate School (U.S.), and Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS)

Subjects
Astrofísica, stars: abundances, High resolution, FOS: Physical sciences, Scale (descriptive set theory), Astrophysics, Type (model theory), Parameter space, Surveys, 01 natural sciences, fundamental parameters [Stars], Spectral line, surveys, 0103 physical sciences, Stars, fundamental parameters, methods, data analysis, data analysis [Methods], 010303 astronomy & astrophysics, methods: data analysis, surveys, stars: abundances, stars: fundamental parameters, stars: late-type, Solar and Stellar Astrophysics (astro-ph.SR), QC, Astronomía y Astrofísica, QB, Physics, 010308 nuclear & particles physics, stars: late-type, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], methods: data analysis, Stars, abundances, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Astronomía, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Globular cluster, abundances [Stars], late-type [Stars], Stars, late type, stars: fundamental parameters, Dispersion (chemistry)
Abstract

The Gaia-ESO Survey is obtaining high-quality spectroscopic data for about 10^5 stars using FLAMES at the VLT. UVES high-resolution spectra are being collected for about 5000 FGK-type stars. These UVES spectra are analyzed in parallel by several state-of-the-art methodologies. Our aim is to present how these analyses were implemented, to discuss their results, and to describe how a final recommended parameter scale is defined. We also discuss the precision (method-to-method dispersion) and accuracy (biases with respect to the reference values) of the final parameters. These results are part of the Gaia-ESO 2nd internal release and will be part of its 1st public release of advanced data products. The final parameter scale is tied to the one defined by the Gaia benchmark stars, a set of stars with fundamental atmospheric parameters. A set of open and globular clusters is used to evaluate the physical soundness of the results. Each methodology is judged against the benchmark stars to define weights in three different regions of the parameter space. The final recommended results are the weighted-medians of those from the individual methods. The recommended results successfully reproduce the benchmark stars atmospheric parameters and the expected Teff-log g relation of the calibrating clusters. Atmospheric parameters and abundances have been determined for 1301 FGK-type stars observed with UVES. The median of the method-to-method dispersion of the atmospheric parameters is 55 K for Teff, 0.13 dex for log g, and 0.07 dex for [Fe/H]. Systematic biases are estimated to be between 50-100 K for Teff, 0.10-0.25 dex for log g, and 0.05-0.10 dex for [Fe/H]. Abundances for 24 elements were derived: C, N, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, Nd, and Eu. The typical method-to-method dispersion of the abundances varies between 0.10 and 0.20 dex., Comment: 39 pages, A&A accepted

Published
2016

17. The Gaia-ESO Survey: Pre-main-sequence stars in the young open cluster NGC 3293

Author

Sergey E. Koposov, S. G. Sousa, A. Hourihane, Alex Lobel, G. G. Sacco, Giovanni Carraro, Emilio J. Alfaro, T. Semaan, L. Morbidelli, A. C. Lanzafame, Jack Lewis, Antonio Frasca, Carmela Lardo, Janet E. Drew, Ettore Flaccomio, V. M. Kalari, Andrew R. Casey, L. Prisinzano, M. T. Costado, Gerard Gilmore, Sofia Randich, J. Eislöffel, Giuseppina Micela, R. D. Jeffries, Antonio Delgado, R. Blomme, J. L. Yun, Antonella Vallenari, Lorenzo Monaco, L. Sampedro, Laura Magrini, Thierry Morel, E. Franciosini, Clare Worley, Gilmore, Gerard [0000-0003-4632-0213], Koposov, Sergey [0000-0003-2644-135X], Worley, Clare [0000-0001-9310-2898], Casey, Andrew [0000-0003-0174-0564], Apollo - University of Cambridge Repository, European Commission, Leverhulme Trust, European Science Foundation, Ministerio de Economía y Competitividad (España), Delgado A.J., Sampedro L., Alfaro E.J., Costado M.T., Yun J.L., Frasca A., Lanzafame A.C., Drew J.E., Eisloffel J., Blomme R., Morel T., Lobel A., Semaan T., Randich S., Jeffries R.D., Micela G., Vallenari A., Kalari V., Gilmore G., Flaccomio E., Carraro G., Lardo C., Monaco L., Prisinzano L., Sousa S.G., Morbidelli L., Lewis J., Koposov S., Hourihane A., Worley C., Casey A., Franciosini E., Sacco G., and Magrini L

Subjects
010504 meteorology & atmospheric sciences, Parametric analysis, Open clusters and associations: general, Open clusters and associations: individual: NGC 3293, Stars: pre-main-sequence, Astronomy and Astrophysics, Space and Planetary Science, stars: pre-main-sequence, Astrophysics, open clusters and associations: general, open clusters and associations: individual: NGC3293, 01 natural sciences, Photometry (optics), pre-main sequence [Stars], 0103 physical sciences, 010303 astronomy & astrophysics, QC, 0105 earth and related environmental sciences, QB, pre-main-sequence [Stars], Physics, general [Open clusters and associations], open clusters and associations: individual: NGC 3293, Astronomy, individual: NGC 3293 [Open clusters and associations], Radial velocity, Stars, Main sequence, Open cluster
Abstract

Delgado, Antonio J. et. al., The young open cluster NGC3293 is included in the observing program of the Gaia-ESO survey (GES). The radial velocity values provided have been used to assign cluster membership probabilities by means of a single-variable parametric analysis. These membership probabilities are compared to the results of the photometric membership assignment of NGC3293, based on UBVRI photometry. The agreement of the photometric and kinematic member samples amounts to 65 per cent, and could increase to 70 per cent as suggested by the analysis of the differences between both samples. A number of photometric PMS candidate members of spectral type F are found, which are confirmed by the results from VPHAS photometry and SED fitting for the stars in common with VPHAS and GES data sets. Excesses at mid- and near-infrared wavelengths, and signs of H alpha emission, are investigated for them. Marginal presence of H alpha emission or infilling is detected for the candidate members. Several of them exhibit moderate signs of U excess and weak excesses at mid-IR wavelengths. We suggest that these features originate from accretion discs in their last stages of evolution., This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541. We acknowledge the support from INAF and Ministero dell' Istruzione, dell' Universita' e della Ricerca (MIUR) in the form of the grant 'Premiale VLT 2012'. The results presented here benefit from discussions held during the Gaia-ESO workshops and conferences supported by the ESF (European Science Foundation) through the GREAT Research Network Programme. AJD, LS, EJA and MTC acknowledge financial support from the Spanish Ministerio de Economia y Competitividad, through grant AYA2013-40611-P. JLY acknowledges support from FCT (SFRH/BSAB/1423/2014 and UID/FIS/04434/2013). TM acknowledges financial support from Belspo for contract PRODEX GAIA-DPAC.

Published
2016

18. Gaia -ESO Survey: Analysis of pre-main sequence stellar spectra

Author

Antonio Frasca, G. G. Sacco, Ignacio Negueruela, Hugo M. Tabernero, Andreas Korn, Martin Asplund, C. Babusiaux, Loredana Prisinzano, Francesco Damiani, Nigel Hambly, M. T. Costado, G. Carraro, Gerry Gilmore, Giuseppina Micela, Emilio J. Alfaro, Piercarlo Bonifacio, Annette M. N. Ferguson, A. Hourihane, Maria Bergemann, N. A. Walton, E. Brugaletta, Manuel Meyer, John D. Lewis, H. W. Rix, Michael G. Irwin, Vardan Adibekyan, R. Blomme, P. Francois, R. D. Jeffries, A. C. Lanzafame, Sergey E. Koposov, Lorenzo Spina, James Binney, Thomas Masseron, L. Morbidelli, D. Montes, K. Biazzo, S. G. Sousa, Antonella Vallenari, Rodolfo Smiljanic, J. M. Alcalá, Thomas Bensby, C. Allende Prieto, Sergio Messina, Luca Sbordone, Amelia Bayo, A. Bragaglia, Simone Zaggia, C. C. Worley, Janet E. Drew, Ettore Flaccomio, S. Van Eck, Paula Jofre, Laura Magrini, Bengt Edvardsson, Gianni Marconi, J. I. González Hernández, Michiel Cottaar, Rosaria Bonito, Lorenzo Monaco, Ulrike Heiter, J. F. Gameiro, Carmela Lardo, Sofia Feltzing, E. Franciosini, T. Prusti, R. J. Jackson, Vanessa Hill, Sofia Randich, Karin Lind, Ch. Martayan, E. Delgado Mena, A. Klutsch, INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), University of Turin, INAF - Osservatorio Astrofisico di Arcetri (OAA), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto, Istituto di Astrofisica Spaziale e Fisica cosmica - Palermo (IASF-Pa), Keele University [Keele], Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), School of Physics, Astronomy and Mathematics [Hatfield], University of Hertfordshire [Hatfield] (UH), Lund Observatory, Lund University [Lund], INAF - Osservatorio Astronomico di Palermo (OAPa), Departamento de Fisica, Ingenieria de Sistemas y Teoria de la Señal [Alicante] (DFESTS), Universidad de Alicante, Agence Spatiale Européenne (ESA), European Space Agency (ESA), Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Royal Observatory of Belgium [Brussels] (ROB), INAF - Osservatorio Astronomico di Bologna (OABO), Institut d'Astronomie et d'Astrophysique, Université libre de Bruxelles (ULB), Uppsala University, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Max-Planck-Institut für Astrophysik (MPA), Max-Planck-Gesellschaft, Istituto Nazionale di Fisica Nucleare, Sezione di Milano (INFN), Istituto Nazionale di Fisica Nucleare (INFN), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lanzafame A.C., Frasca A., Damiani F., Franciosini E., Cottaar M., Sousa S.G., Tabernero H.M., Klutsch A., Spina L., Biazzo K., Prisinzano L., Sacco G.G., Randich S., Brugaletta E., Delgado Mena E., Adibekyan V., Montes D., Bonito R., Gameiro J.F., Alcala J.M., Gonzalez Hernandez J.I., Jeffries R., Messina S., Meyer M., Gilmore G., Asplund M., Binney J., Bonifacio P., Drew J.E., Feltzing S., Ferguson A.M.N., Micela G., Negueruela I., Prusti T., Rix H.-W., Vallenari A., Alfaro E.J., Allende Prieto C., Babusiaux C., Bensby T., Blomme R., Bragaglia A., Flaccomio E., Francois P., Hambly N., Irwin M., Koposov S.E., Korn A.J., Smiljanic R., Van Eck S., Walton N., Bayo A., Bergemann M., Carraro G., Costado M.T., Edvardsson B., Heiter U., Hill V., Hourihane A., Jackson R.J., Jofre P., Lardo C., Lewis J., Lind K., Magrini L., Marconi G., Martayan C., Masseron T., Monaco L., Morbidelli L., Sbordone L., Worley C.C., Zaggia S., Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Astrofísica Estelar (AE), Lanzafame, A., Frasca, A., Damiani, F., Franciosini, E., Cottaar, M., Sousa, S., Tabernero, H., Klutsch, A., Spina, L., Biazzo, K., Prisinzano, L., Sacco, G., Randich, S., Brugaletta, E., Delgado Mena, E., Adibekyan, V., Montes, D., Bonito, R., Gameiro, J., Alcalá, J., González Hernández, J., Jeffries, R., Messina, S., Meyer, M., Gilmore, G., Asplund, M., Binney, J., Bonifacio, P., Drew, J., Feltzing, S., Ferguson, A., Micela, G., Negueruela, I., Prusti, T., Rix, H., Vallenari, A., Alfaro, E., Allende Prieto, C., Babusiaux, C., Bensby, T., Blomme, R., Bragaglia, A., Flaccomio, E., Francois, P., Hambly, N., Irwin, M., Koposov, S., Korn, A., Smiljanic, R., Van Eck, S., Walton, N., Bayo, A., Bergemann, M., Carraro, G., Costado, M., Edvardsson, B., Heiter, U., Hill, V., Hourihane, A., Jackson, R., Jofré, P., Lardo, C., Lewis, J., Lind, K., Magrini, L., Marconi, G., Martayan, C., Masseron, T., Monaco, L., Morbidelli, L., Sbordone, L., Worley, C., and Zaggia, S.

Subjects
Accuracy and precision, Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, stars: pre-main sequence, Surveys, fundamental parameters [Stars], Astronomical spectroscopy, surveys, Angular diameter, pre-main sequence [Stars], Astrophysics::Solar and Stellar Astrophysics, Survey, data analysis [Methods], education, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astronomía y Astrofísica, Physics, education.field_of_study, general [Open clusters and associations], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Stars: fundamental parameter, Astronomy and Astrophysic, Effective temperature, open clusters and associations: general, Surface gravity, methods: data analysis, Accretion (astrophysics), Stars, Astrophysics - Solar and Stellar Astrophysics, Methods: data analysis, Open clusters and associations: general, Stars: fundamental parameters, Stars: pre-main sequence, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics, stars: fundamental parameters, Methods: data analysi
Abstract

This paper describes the analysis of UVES and GIRAFFE spectra acquired by the Gaia-ESO Public Spectroscopic Survey in the fields of young clusters whose population includes pre-main sequence (PMS) stars. Both methods that have been extensively used in the past and new ones developed in the contest of the Gaia-ESO survey enterprise are available and used. The internal precision of these quantities is estimated by inter-comparing the results obtained by such different methods, while the accuracy is estimated by comparison with independent external data, like effective temperature and surface gravity derived from angular diameter measurements, on a sample of benchmarks stars. Specific strategies are implemented to deal with fast rotation, accretion signatures, chromospheric activity, and veiling. The analysis carried out on spectra acquired in young clusters' fields during the first 18 months of observations, up to June 2013, is presented in preparation of the first release of advanced data products. Stellar parameters obtained with the higher resolution and larger wavelength coverage from UVES are reproduced with comparable accuracy and precision using the smaller wavelength range and lower resolution of the GIRAFFE setup adopted for young stars, which allows us to provide with confidence stellar parameters for the much larger GIRAFFE sample. Precisions are estimated to be $\approx$ 120 K r.m.s. in Teff, $\approx$0.3 dex r.m.s. in logg, and $\approx$0.15 dex r.m.s. in [Fe/H], for both the UVES and GIRAFFE setups., 22 pages, 18 figures, accepted for publication on A&A

Published
2015

19. The Gaia -ESO Survey: Tracing interstellar extinction

Author

P. Francois, Gerard Gilmore, P. de Laverny, Carmela Lardo, Sofia Feltzing, Ettore Flaccomio, Georges Kordopatis, Paula Jofre, A. C. Lanzafame, Simone Zaggia, L. Prisinzano, Mathias Schultheis, Vanessa Hill, C. C. Worley, Emilio J. Alfaro, Alejandra Recio-Blanco, A. Hourihane, Francesco Damiani, F. M. Jiménez-Esteban, M. T. Costado, L. Morbidelli, Thomas Bensby, Schultheis M., Kordopatis G., Recio-Blanco A., De Laverny P., Hill V., Gilmore G., Alfaro E.J., Costado M.T., Bensby T., Damiani F., Feltzing S., Flaccomio E., Lardo C., Jofre P., Prisinzano L., Zaggia S., Jimenez-Esteban F., Morbidelli L., Lanzafame A.C., Hourihane A., Worley C., Francois P., Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), University of Turin, Lund Observatory, Lund University [Lund], Ecole Polytechnique Fédérale de Lausanne (EPFL), INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), Institut de Mécanique des Fluides et des Solides (IMFS), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Computation, Extinction (astronomy), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Tracing, 01 natural sciences, Photometry (optics), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Galaxy: structure, Astrophysics::Galaxy Astrophysics, Dust, extinction, Physics, [PHYS]Physics [physics], Galaxy: stellar content, 010308 nuclear & particles physics, extinction, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Molar absorptivity, Astrophysics - Astrophysics of Galaxies, Galaxy, Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Galaxy: structure, dust, extinction, Galaxy: stellar content, dust, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Data release
Abstract

Large spectroscopic surveys have enabled in the recent years the computation of three-dimensional interstellar extinction maps thanks to accurate stellar atmospheric parameters and line-of-sight distances. Such maps are complementary to 3D maps extracted from photometry, allowing a more thorough study of the dust properties. Our goal is to use the high-resolution spectroscopic survey Gaia-ESO in order to obtain with a good distance resolution the interstellar extinction and its dependency as a function of the environment and the Galactocentric position. We use the stellar atmospheric parameters of more than 5000 stars, obtained from the Gaia-ESO survey second internal data release, and combine them with optical (SDSS) and near-infrared (VISTA) photometry as well as different sets of theoretical stellar isochrones, in order to calculate line-of-sight extinction and distances. The extinction coefficients are then compared with the literature to discuss their dependancy on the stellar parameters and position in the Galaxy. Within the errors of our method, our work does not show that there is any dependence of the interstellar extinction coefficient on the atmospheric parameters of the stars. We do not find any evidence of the variation of E(J-H)/E(J-K) with the angle from the Galactic centre nor with Galactocentric distance. This suggests that we are dealing with a uniform extinction law in the SDSS ugriz bands and the near-IR JHKs bands. Therefore, extinction maps using mean colour-excesses and assuming a constant extinction coefficient can be used without introducing any systematic errors., Comment: 13 pages, 14 figures, 1 Appendix accepted for publication in Astronomy&Astrophysics

Published
2015

20. The Gaia-ESO Survey: Chromospheric emission, accretion properties, and rotation in gamma Velorum and Chamaeleon

Author

A. Hourihane, Geert Barentsen, E. Brugaletta, Beate Stelzer, Gerry Gilmore, Paula Jofre, E. Franciosini, Thomas Masseron, G. Pace, K. Biazzo, L. Morbidelli, Luca Pasquini, Emilio J. Alfaro, A. C. Lanzafame, Lorenzo Spina, R. Bonito, Carmela Lardo, Sofia Randich, A. Bragaglia, M. T. Costado, A. Klutsch, C. C. Worley, Enrico Maiorca, S. G. Sousa, Antonio Frasca, J. F. Gameiro, G. G. Sacco, Loredana Prisinzano, Giuseppina Micela, J. M. Alcalá, V. Hill, D. Montes, Javier Lopez-Santiago, Amelia Bayo, R. D. Jeffries, Ettore Flaccomio, ITA, Frasca A., Biazzo K., Lanzafame A.C., Alcala J.M., Brugaletta E., Klutsch A., Stelzer B., Sacco G.G., Spina L., Jeffries R.D., Montes D., Alfaro E.J., Barentsen G., Bonito R., Gameiro J.F., Lopez-Santiago J., Pace G., Pasquini L., Prisinzano L., Sousa S.G., Gilmore G., Randich S., Micela G., Bragaglia A., Flaccomio E., Bayo A., Costado M.T., Franciosini E., Hill V., Hourihane A., Jofre P., Lardo C., Maiorca E., Masseron T., Morbidelli L., Worley C.C., Frasca, A., Biazzo, K., Lanzafame, A., Alcalá, J., Brugaletta, E., Klutsch, A., Stelzer, B., Sacco, G., Spina, L., Jeffries, R., Montes, D., Alfaro, E., Barentsen, G., Bonito, R., Gameiro, J., López-Santiago, J., Pace, G., Pasquini, L., Prisinzano, L., Sousa, S., Gilmore, G., Randich, S., Micela, G., Bragaglia, A., Flaccomio, E., Bayo, A., Costado, M., Franciosini, E., Hill, V., Hourihane, A., Jofré, P., Lardo, C., Maiorca, E., Masseron, T., Morbidelli, L., and Worley, C.

Subjects
Astrofísica, stars: chromospheres, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rotation, Stars: chromosphere, Open clusters and associations: individual:γVelorum, stars: low-mass, Stars: low-ma, Astrophysics::Solar and Stellar Astrophysics, Open clusters and associations: individual: Chamaeleon I, open clusters and associations: individual: γ Velorum, QC, Astrophysics::Galaxy Astrophysics, QB, Line (formation), Physics, Accretion (meteorology), Diagram, Stars: rotation, Spectral density, Astronomy and Astrophysics, Astronomy and Astrophysic, Stars, Distribution (mathematics), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Chamaeleon, Stars: pre-main sequence, Astrophysics::Earth and Planetary Astrophysics, Stars: chromospheres, Stars: low-mass
Abstract

Aims: One of the goals of the Gaia-ESO Survey (GES), which is conducted with FLAMES at the VLT, is the census and the characterization of the low-mass members of very young clusters and associations. We conduct a comparative study of the main properties of the sources belonging to γ Velorum (γ Vel) and Chamaeleon I (Cha I) young associations, focusing on their rotation, chromospheric radiative losses, and accretion. Methods: We used the fundamental parameters (effective temperature, surface gravity, lithium abundance, and radial velocity) delivered by the GES consortium in the first internal data release to select the members of γ Vel and Cha I among the UVES and GIRAFFE spectroscopic observations. A total of 140 γ Vel members and 74 Cha I members were studied. The procedure adopted by the GES to derive stellar fundamental parameters also provided measures of the projected rotational velocity (vsini). We calculated stellar luminosities through spectral energy distributions, while stellar masses were derived by comparison with evolutionary tracks. The spectral subtraction of low-activity and slowly rotating templates, which are rotationally broadened to match the vsini of the targets, enabled us to measure the equivalent widths (EWs) and the fluxes in the Hα and Hβ lines. The Hα line was also used for identifying accreting objects, on the basis of its EW and the width at the 10% of the line peak (10%W), and for evaluating the mass accretion rate (Ṁacc). Results: The distribution of vsini for the members of γ Vel displays a peak at about 10 km s-1 with a tail toward faster rotators. There is also some indication of a different vsini distribution for the members of its two kinematical populations. Most of these stars have Hα fluxes corresponding to a saturated activity regime. We find a similar distribution, but with a narrower peak, for Cha I. Only a handful of stars in γ Vel display signatures of accretion, while many more accretors were detected in the younger Cha I, where the highest Hα fluxes are mostly due to accretion, rather than to chromospheric activity. Accreting and active stars occupy two different regions in a Teff-flux diagram and we propose a criterion for distinguishing them. We derive Ṁacc in the ranges 10-11-10-9 M☉ yr-1 and 10-10-10-7 M☉ yr-1 for γ Vel and Cha I accretors, respectively. We find less scatter in the Ṁacc - M⋆ relation derived through the Hα EWs, when compared to the Hα10%W diagnostics, in agreement with other authors. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002.Tables 5, 6, and Appendix A are available in electronic form at http://www.aanda.orgTables 2-4 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/575/A4

Published
2015

21. The Gaia-ESO Survey: Catalogue of Hα emission stars

Author

Carmela Lardo, Angela Bragaglia, L. Morbidelli, Clare Worley, A. Klutsch, A. C. Lanzafame, Antonio Frasca, Francesco Damiani, Amelia Bayo, Gregor Traven, G. G. Sacco, Rosaria Bonito, F. M. Jiménez-Esteban, M. T. Costado, Ettore Flaccomio, S. Van Eck, Emilio J. Alfaro, Loredana Prisinzano, Tomaz Zwitter, A. Hourihane, Elena Pancino, Traven, G., Zwitter, T., Van Eck, S., Klutsch, A., Bonito, R., Lanzafame, A., Alfaro, E., Bayo, A., Bragaglia, A., Costado, M., Damiani, F., Flaccomio, E., Frasca, A., Hourihane, A., Jimenez-Esteban, F., Lardo, C., Morbidelli, L., Pancino, E., Prisinzano, L., Sacco, G., Worley, C., Traven G., Zwitter T., Van Eck S., Klutsch A., Bonito R., Lanzafame A.C., Alfaro E.J., Bayo A., Bragaglia A., Costado M.T., Damiani F., Flaccomio E., Frasca A., Hourihane A., Jimenez-Esteban F., Lardo C., Morbidelli L., Pancino E., Prisinzano L., Sacco G.G., and Worley C.C.

Subjects
Physics, catalog, Stars: emission-line, Be, Star formation, Astrophysics::High Energy Astrophysical Phenomena, SIMBAD, stars: peculiar, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, open clusters and associations: general, Astronomy and Astrophysic, Spectral line, Stars, line: profile, 13. Climate action, Space and Planetary Science, Stellar physics, stars: activity, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, Astrophysics::Galaxy Astrophysics, Open cluster, Line (formation)
Abstract

We discuss the properties of Hα emission stars across the sample of 22035 spectra from the Gaia-ESO Survey internal data release, observed with the GIRAFFE instrument and largely belonging to stars in young open clusters. Automated fits using two independent Gaussian profiles and a third component that accounts for the nebular emission allow us to discern distinct morphological types of Hα line profiles with the introduction of a simplified classification scheme. All in all, we find 3765 stars with intrinsic emission and sort their spectra into eight distinct morphological categories: single-component emission, emission blend, sharp emission peaks, double emission, P-Cygni, inverted P-Cygni, self-absorption, and emission in absorption. We have more than one observation for 1430 stars in our sample, thus allowing a quantitative discussion of the degree of variability of Hα emission profiles, which is expected for young, active objects. We present a catalogue of stars with properties of their Hα emission line profiles, morphological classification, analysis of variability with time and the supplementary information from the SIMBAD, VizieR, and ADS databases. The records in SIMBAD indicate the presence of Hα emission for roughly 25% of all stars in our catalogue, while at least 305 of them have already been more thoroughly investigated according to the references in ADS. The most frequently identified morphological categories in our sample of spectra are emission blend (23%), emission in absorption (22%), and self-absorption (16%). Objects with repeated observations demonstrate that our classification into discrete categories is generally stable through time, but categories P-Cygni and self-absorption seem less stable, which is the consequence of discrete classification rules, as well as of the fundamental change in profile shape. Such records of emission stars can be valuable for automatic pipelines in large surveys, where it may prove very useful for pinpointing outliers when calculating general stellar properties and elemental abundances. They can be used in studies of star formation processes, interacting binaries, and other fields of stellar physics. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002.Full Tables D.1-D.3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/581/A52

Published
2015

22. The Gaia-ESO Survey: Abundance ratios in the inner-disk open clusters Trumpler 20, NGC 4815, NGC 6705

Author

Gerard Gilmore, F. M. Jiménez-Esteban, Ulrike Heiter, Vanessa Hill, Jack Lewis, Lorenzo Spina, P. Donati, A. Hourihane, E. Friel, Grazina Tautvaisiene, E. Franciosini, Sergey E. Koposov, Enrico Maiorca, Carmela Lardo, Andreas Korn, Rodolfo Smiljanic, Sofia Feltzing, Antonella Vallenari, Monica Tosi, R. J. Jackson, Martin Asplund, Angela Bragaglia, Thomas Masseron, Heather R. Jacobson, P. Francois, C. Muñoz, P. de Laverny, Clare Worley, Nami Mowlavi, R. D. Jeffries, Maria Bergemann, I. San Roman, S. Villanova, S. Blanco-Cuaresma, Francesco Damiani, Tristan Cantat-Gaudin, Alejandra Recio-Blanco, Sofia Randich, Karin Lind, Donatella Romano, Ettore Flaccomio, Caroline Soubiran, Laura Magrini, Douglas Geisler, Paula Jofre, Simone Zaggia, Loredana Prisinzano, R. Sordo, G. G. Sacco, L. Morbidelli, Thomas Bensby, Elena Pancino, M. T. Costado, Laboratoire des Agrégats Moléculaires et Matériaux Inorganiques (LAMMI), Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2), M2A 2014, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Department of Astronomy and Space Physics [Uppsala], Uppsala University, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Magrini L., Randich S., Romano D., Friel E., Bragaglia A., Smiljanic R., Jacobson H., Vallenari A., Tosi M., Spina L., Donati P., Maiorca E., Cantat-Gaudin T., Sordo R., Bergemann M., Damiani F., Tautvaisiene G., Blanco-Cuaresma S., Jimenez-Esteban F., Geisler D., Mowlavi N., Munoz C., San Roman I., Soubiran C., Villanova S., Zaggia S., Gilmore G., Asplund M., Feltzing S., Jeffries R., Bensby T., Koposov S., Korn A.J., Flaccomio E., Pancino E., Recio-Blanco A., Sacco G., Costado M.T., Franciosini E., Jofre P., De Laverny P., Hill V., Heiter U., Hourihane A., Jackson R., Lardo C., Morbidelli L., Lewis J., Lind K., Masseron T., Prisinzano L., and Worley C.

Subjects
[PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Globular clusters: individual: NGC 6705, Metallicity, astro-ph.GA, FOS: Physical sciences, Astrophysics, Galaxy: disk, Open clusters and associations: individual: NGC 4815, Bulge, Abundance (ecology), Disc, Galaxy: abundances, Open clusters and associations: general, Open clusters and associations: individual: Trumpler 20, Physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Galaxy: abundance, Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Content (measure theory), Open cluster
Abstract

Open clusters are key tools to study the spatial distribution of abundances in the disk and their evolution with time. Using the first release of stellar parameters and abundances of the Gaia-ESO Survey, we analyse the chemical properties of stars in three old/intermediate-age open clusters, namely NGC 6705, NGC 4815, and Trumpler 20, all located in the inner part of the Galactic disk at Galactocentric radius R$_{GC}\sim$7 kpc, aiming at proving their homogeneity and at comparing them with the field population. We study the abundance ratios of elements belonging to two different nucleosynthetic channels: $\alpha$-elements and iron-peak elements. The main results can be summarised as follows: i) cluster members are chemically homogeneous within 3-$\sigma$ in all analysed elements; ii) the three clusters have comparable [El/Fe] patters within $\sim$1-$\sigma$, but they differ in their global metal content [El/H], with NGC 4815 having the lowest metallicity. Their [El/Fe] ratios show differences and analogies with those of the field population, both in the solar neighbourhood and in the bulge/inner disk; iii) comparing the abundance ratios with the results of two chemical evolution models and with field star abundance distributions, we find that the abundance ratios of Mg, Ni, Ca in NGC 6705 might require an inner birthplace, implying a subsequent variation of its R$_{GC}$ during its lifetime, consistent with previous orbit determination. The full dataset of the Gaia-ESO Survey will be a superlative tool to constrain the chemical evolution of our Galaxy by disentangling different formation and evolution scenarios., Comment: 17 pages, 11 figures, A&A accepted

Published
2014

23. The Gaia-ESO Survey: the most metal-poor stars in the Galactic bulge

Author

Alejandra Recio-Blanco, David M. Nataf, Sofia Randich, Karin Lind, A. Hourihane, Carmela Lardo, Sofia Feltzing, G. G. Sacco, Martin Asplund, C. C. Worley, Paula Jofre, Andreas Korn, David Yong, C. Allende Prieto, L. M. Howes, G. S. Da Costa, Enrico Maiorca, Manuela Zoccali, Francesco Damiani, L. Morbidelli, Vanessa Hill, Maria Bergemann, Ulrike Heiter, Andrew R. Casey, Rodolfo Smiljanic, Gerard Gilmore, Stefan Keller, Michael S. Bessell, Dante Minniti, Patrick Tisserand, Laura Magrini, Anna F. Marino, Brian P. Schmidt, Antonella Vallenari, Thomas Masseron, Luca Casagrande, Ettore Flaccomio, P. de Laverny, Elena Pancino, Thomas Bensby, Christopher Owen, M. T. Costado, Howes L.M., Asplund M., Casey A.R., Keller S.C., Yong D., Gilmore G., Lind K., Worley C., Bessell M.S., Casagrande L., Marino A.F., Nataf D.M., Owen C.I., Da Costa G.S., Schmidt B.P., Tisserand P., Randich S., Feltzing S., Vallenari A., Allende Prieto C., Bensby T., Flaccomio E., Korn A.J., Pancino E., Recio-Blanco A., Smiljanic R., Bergemann M., Costado M.T., Damiani F., Heiter U., Hill V., Hourihane A., Jofre P., Lardo C., de Laverny P., Magrini L., Maiorca E., Masseron T., Morbidelli L., Sacco G.G., Minniti D., and Zoccali M.

Subjects
010504 meteorology & atmospheric sciences, Evolution, Metallicity, K-type main-sequence star, Milky Way, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Bulge, 0103 physical sciences, Galaxy formation and evolution, Population II-Galaxy, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Spiral galaxy, Bulge-Galaxy, Astronomy, Astronomy and Astrophysics, Stars, Astrophysics - Astrophysics of Galaxies, Galaxy, Abundances-star, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract

We present the first results of the EMBLA survey (Extremely Metal-poor BuLge stars with AAOmega), aimed at finding metal-poor stars in the Milky Way bulge, where the oldest stars should now preferentially reside. EMBLA utilises SkyMapper photometry to pre-select metal-poor candidates, which are subsequently confirmed using AAOmega spectroscopy. We describe the discovery and analysis of four bulge giants with -2.72, Comment: 7 pages, 5 figures. Accepted for publication by MNRAS

Published
2014
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24. The Gaia-ESO survey: Metallicity of the chamaeleon i star-forming region

Author

Antonio Frasca, A. Hourihane, Gerard Gilmore, M. T. Costado, Elisa Delgado-Mena, Angela Bragaglia, V. Adibekyan, A. C. Lanzafame, Rosaria Bonito, Lorenzo Spina, Ettore Flaccomio, Paula Jofre, D. Montes, Maria Bergemann, Carmela Lardo, Laura Magrini, Franco Palla, K. Biazzo, Alejandra Recio-Blanco, S. G. Sousa, Rodolfo Smiljanic, Thomas Masseron, Loredana Prisinzano, Antonella Vallenari, G. G. Sacco, L. Morbidelli, P. de Laverny, Clare Worley, Vanessa Hill, Grazina Tautvaisiene, Hugo M. Tabernero, Andreas Korn, Francesco Damiani, Elena Pancino, Thomas Bensby, Sofia Randich, J. I. González Hernández, Emilio J. Alfaro, E. Franciosini, R. D. Jeffries, Spina L., Randich S., Palla F., Biazzo K., Sacco G.G., Alfaro E.J., Franciosini E., Magrini L., Morbidelli L., Frasca A., Adibekyan V., Delgado-Mena E., Sousa S.G., Gonzalez Hernandez J.I., Montes D., Tabernero H., Tautvaisiene G., Bonito R., Lanzafame A.C., Gilmore G., Jeffries R.D., Vallenari A., Bensby T., Bragaglia A., Flaccomio E., Korn A.J., Pancino E., Recio-Blanco A., Smiljanic R., Bergemann M., Costado M.T., Damiani F., Hill V., Hourihane A., Jofre P., De Laverny P., Lardo C., Masseron T., Prisinzano L., Worley C.C., Spina, L., Randich, S., Palla, F., Biazzo, K., Sacco, G. G., Alfaro, E. J., Franciosini, E., Magrini, L., Morbidelli, L., Frasca, A., Adibekyan, V., Delgado-Mena, E., Sousa, S. G., González Hernández, J. I., Montes, D., Tabernero, H., Tautvaišienė, G., Bonito, R., Lanzafame, A. C., Gilmore, G., Jeffries, R. D., Vallenari, A., Bensby, T., Bragaglia, A., Flaccomio, E., Korn, A. J., Pancino, E., Recio-Blanco, A., Smiljanic, R., Bergemann, M., Costado, M. T., Damiani, F., Hill, V., Hourihane, A., Jofré, P., de Laverny, P., Lardo, C., Masseron, T., Prisinzano, L., and Worley, C. C.

Subjects
Astrofísica, Stars: abundance, Metallicity, FOS: Physical sciences, Techniques: spectroscopic, Context (language use), Astrophysics, Open clusters and associations: individual: Chamaeleon I, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), Physics, 85A04, open clusters and associations: individual: Chamaeleon I, stars: pre-main sequence, stars: abundances, techniques: spectroscopic, Stars: abundances, Astronomy and Astrophysics, Surface gravity, Astronomía, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Chamaeleon, Stars: pre-main sequence, individual: Chamaeleon I, stars: pre-main sequence, stars: abundances, techniques: spectroscopic [open clusters and associations], Equivalent width, Open cluster
Abstract

Context. Recent metallicity determinations in young open clusters and star-forming regions suggest that the latter may be characterized by a slightly lower metallicity than the Sun and older clusters in the solar vicinity. However, these results are based on small statistics and inhomogeneous analyses. The Gaia-ESO Survey is observing and homogeneously analyzing large samples of stars in several young clusters and star-forming regions, hence allowing us to further investigate this issue. Aims. We present a new metallicity determination of the Chamaeleon I star-forming region, based on the products distributed in the first internal release of the Gaia-ESO Survey. Methods. 48 candidate members of Chamaeleon I have been observed with the high-resolution spectrograph UVES. We use the surface gravity, lithium line equivalent width and position in the Hertzsprung-Russell diagram to confirm the cluster members and we use the iron abundance to derive the mean metallicity of the region. Results. Out of the 48 targets, we confirm 15 high probability members. Considering the metallicity measurements for 9 of them, we find that the iron abundance of Chamaeleon I is slightly subsolar with a mean value [Fe/H]=-0.08+/-0.04 dex. This result is in agreement with the metallicity determination of other nearby star-forming regions and suggests that the chemical pattern of the youngest stars in the solar neighborhood is indeed more metal-poor than the Sun. We argue that this evidence may be related to the chemical distribution of the Gould Belt that contains most of the nearby star-forming regions and young clusters., Comment: 13 pages, 11 figures, 3 tables, Accepted for publication in Astronomy & Astrophysics

Published
2014

25. TheGaia-ESO Survey:α-abundances of metal-poor stars

Author

Thomas Bensby, A. Hourihane, Rodolfo Smiljanic, C. C. Worley, Carmela Lardo, Antonella Vallenari, Gerard Gilmore, Georges Kordopatis, Keith Hawkins, Alejandra Recio-Blanco, Simone Zaggia, Ulrike Heiter, M. T. Costado, Šarūnas Mikolaitis, R. Jackson-Jones, Angela Bragaglia, Guillaume Guiglion, Vanessa Hill, P. de Laverny, Ettore Flaccomio, Paula Jofre, Grazina Tautvaisiene, Andreas Korn, Sofia Randich, Jackson-Jones R., Jofre P., Hawkins K., Hourihane A., Gilmore G., Kordopatis G., Worley C., Randich S., Vallenari A., Bensby T., Bragaglia A., Flaccomio E., Korn A.J., Recio-Blanco A., Smiljanic R., Costado M.T., Heiter U., Hill V., Lardo C., De Laverny P., Guiglion G., Mikolaitis S., Zaggia S., and Tautvaisiene G.

Subjects
endocrine system, Metallicity, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Galactic halo, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, QB, Physics, urogenital system, 010308 nuclear & particles physics, Star formation, Stars: abundances, Astronomy and Astrophysics, Radius, Galactic plane, Surface gravity, Astrophysics - Astrophysics of Galaxies, Galaxy: halo, Stars, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Halo
Abstract

We performed a detailed study of the ratio of low-{\alpha} to high-{\alpha} stars in the Galactic halo as observed by the Gaia-ESO Survey. Using a sample of 381 metal-poor stars from the second internal data release, we found that the value of this ratio did not show evidence of systematic trends as a function of metallicity, surface gravity, Galactic latitude, Galactic longitude, height above the Galactic plane, and Galactocentric radius. We conclude that the {\alpha}-poor/{\alpha}-rich value of 0.28 $\pm$ 0.08 suggests that in the inner halo, the larger portion of stars were formed in a high star formation rate environment, and about 15% of the metal-poor stars originated from much lower star formation rate environments.

Published
2014

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