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http://hdl.handle.net/20.500.12386/23197
Title: | Gaia-ESO Survey: Analysis of pre-main sequence stellar spectra | Authors: | Lanzafame, Alessandro Carmelo FRASCA, Antonio DAMIANI, Francesco FRANCIOSINI, Elena Cottaar, M. Sousa, S. G. Tabernero, H. M. Klutsch, A. Spina, L. BIAZZO, Katia PRISINZANO, Loredana SACCO, GIUSEPPE GERMANO RANDICH, Maria Sofia Brugaletta, Elisa Delgado Mena, E. Adibekyan, V. Montes, D. Bonito, Rosaria Gameiro, J. F. ALCALA', JUAN MANUEL González Hernández, J. I. Jeffries, R. MESSINA, Sergio Meyer, M. Gilmore, G. Asplund, M. Binney, J. Bonifacio, P. Drew, J. E. Feltzing, S. Ferguson, A. M. N. MICELA, Giuseppina Negueruela, I. Prusti, T. Rix, H. -W. VALLENARI, Antonella Alfaro, E. J. Allende Prieto, C. Babusiaux, C. Bensby, T. Blomme, R. BRAGAGLIA, Angela FLACCOMIO, Ettore 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. Jofré, P. Lardo, C. Lewis, J. Lind, K. MAGRINI, LAURA Marconi, G. Martayan, C. Masseron, T. Monaco, L. MORBIDELLI, LORENZO Sbordone, L. Worley, C. C. ZAGGIA, Simone |
Issue Date: | 2015 | Journal: | ASTRONOMY & ASTROPHYSICS | Number: | 576 | First Page: | A80 | Abstract: | Context. The Gaia-ESO Public Spectroscopic Survey is obtaining high-quality spectroscopy of some 100 000 Milky Way stars using the FLAMES spectrograph at the VLT, down to V = 19 mag, systematically covering all the main components of the Milky Way and providing the first homogeneous overview of the distributions of kinematics and chemical element abundances in the Galaxy. Observations of young open clusters, in particular, are giving new insights into their initial structure, kinematics, and their subsequent evolution. <BR /> Aims: This paper describes the analysis of UVES and GIRAFFE spectra acquired in the fields of young clusters whose population includes pre-main sequence (PMS) stars. The analysis is applied to all stars in such fields, regardless of any prior information on membership, and provides fundamental stellar atmospheric parameters, elemental abundances, and PMS-specific parameters such as veiling, accretion, and chromospheric activity. <BR /> Methods: When feasible, different methods were used to derive raw parameters (e.g. line equivalent widths) fundamental atmospheric parameters and derived parameters (e.g. abundances). To derive some of these parameters, we used methods that have been extensively used in the past and new ones developed in the context of the Gaia-ESO survey enterprise. The internal precision of these quantities was estimated by inter-comparing the results obtained by these different methods, while the accuracy was estimated by comparison with independent external data, such as effective temperature and surface gravity derived from angular diameter measurements, on a sample of benchmarks stars. A validation procedure based on these comparisons was applied to discard spurious or doubtful results and produce recommended parameters. Specific strategies were implemented to resolve problems of fast rotation, accretion signatures, chromospheric activity, and veiling. <BR /> Results: The analysis carried out on spectra acquired in young cluster fields during the first 18 months of observations, up to June 2013, is presented in preparation of the first release of advanced data products. These include targets in the fields of the <ASTROBJ>ρ Oph</ASTROBJ>, <ASTROBJ>Cha I</ASTROBJ>, <ASTROBJ>NGC 2264</ASTROBJ>, <ASTROBJ>γ Vel</ASTROBJ>, and <ASTROBJ>NGC 2547</ASTROBJ> clusters. 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 stellar parameters with confidence for the much larger GIRAFFE sample. Precisions are estimated to be ≈120 K rms in T<SUB>eff</SUB>, ≈0.3 dex rms in log g, and ≈0.15 dex rms in [Fe/H] for the UVES and GIRAFFE setups. | Acknowledgments: | Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002. 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’ Università e della Ricerca (MIUR) in the form of the grant “Premiale VLT 2012” and the grant “The Chemical and Dynamical Evolution of the Milky Way and Local Group Galaxies” (prot. 2010LY5N2T). 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. H.M.T. acknowledges the financial support from BES-2009-012182 and the ESF and GREAT for an exchange grant 4158. H.M.T. and D.M. acknowledges the financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) under grant AYA2011-30147-C03-02. J.I.G.H. acknowledges financial support from the MINECO under grants AYA2011-29060, and 2011 Severo Ochoa Program SEV-2011-0187. S.G.S, E.D.M., and V.Zh.A. acknowledge support from the Fundação para a Ciência e Tecnologia (Portugal) in the form of grants SFRH/BPD/47611/2008, SFRH/BPD/76606/2011, SFRH/BPD/70574/2010, respectively. T.B. was funded by grant No. 621-2009-3911 from The Swedish Research Council. | URI: | http://hdl.handle.net/20.500.12386/23197 | URL: | https://www.aanda.org/articles/aa/abs/2015/04/aa24759-14/aa24759-14.html | ISSN: | 0004-6361 | DOI: | 10.1051/0004-6361/201424759 | Bibcode ADS: | 2015A&A...576A..80L | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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