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29 results on '"Bijaoui, A."'

1. Apsis. III. Non-stellar content and source classification

Author

Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: As part of the third Gaia Data Release, we present the contributions of the non-stellar and classification modules from the eighth coordination unit (CU8) of the Data Processing and Analysis Consortium, which is responsible for the determination of source astrophysical parameters using Gaia data. This is the third in a series of three papers describing the work done within CU8 for this release. Aims: For each of the five relevant modules from CU8, we summarise their objectives, the methods they employ, their performance, and the results they produce for Gaia DR3. We further advise how to use these data products and highlight some limitations. Methods: The Discrete Source Classifier (DSC) module provides classification probabilities associated with five types of sources: quasars, galaxies, stars, white dwarfs, and physical binary stars. A subset of these sources are processed by the Outlier Analysis (OA) module, which performs an unsupervised clustering analysis, and then associates labels with the clusters to complement the DSC classification. The Quasi Stellar Object Classifier (QSOC) and the Unresolved Galaxy Classifier (UGC) determine the redshifts of the sources classified as quasar and galaxy by the DSC module. Finally, the Total Galactic Extinction (TGE) module uses the extinctions of individual stars determined by another CU8 module to determine the asymptotic extinction along all lines of sight for Galactic latitudes |b| > 5 degrees. Results: Gaia DR3 includes 1591 million sources with DSC classifications; 56 million sources to which the OA clustering is applied; 1.4 million sources with redshift estimates from UGC; 6.4 million sources with QSOC redshift; and 3.1 million level 9 HEALPixes of size 0 :013 deg(2) where the extinction is evaluated by TGE. Conclusions: Validation shows that results are in good agreement with values from external catalogues; for example 90% of the QSOC redshifts have absolute error lower than 0:1 for sources with empty

Published
2023
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2. Gaia Data Release 3 : Astrophysical parameters inference system (Apsis). I. Methods and content overview

Author

Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., Silvester, J., Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., and Silvester, J.

Abstract

Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are a major component of this release, and were produced by the Astrophysical parameters inference system (Apsis) within the Gaia Data Processing and Analysis Consortium (DPAC). The aim of this paper is to describe the overall content of the astrophysical parameters in Gaia DR3 and how they were produced. In Apsis, we use the mean BP /RP and mean RVS spectra along with astrometry and photometry, and we derive the following parameters: source classification and probabilities for 1.6 billion objects; interstellar medium characterisation and distances for up to 470 million sources, including a 2D total Galactic extinction map; 6 million redshifts of quasar candidates; 1.4 million redshifts of galaxy candidates; and an analysis of 50 million outlier sources through an unsupervised classification. The astrophysical parameters also include many stellar spectroscopic and evolutionary parameters for up to 470 million sources. These comprise T-eff, log g, and [M /H] (470 million using BP /RP, 6 million using RVS), radius (470 million), mass (140 million), age (120 million), chemical abundances (up to 5 million), diffuse interstellar band analysis (0.5 million), activity indices (2 million), H ff equivalent widths (200 million), and further classification of spectral types (220 million) and emission-line stars (50 000). This paper is the first in a series of three papers, and focusses on describing the global content of the parameters in Gaia DR3. The accompanying Papers II and III focus on the validation and use of the stellar and non-stellar products, respectively. This catalogue is the most extensive homogeneous database of astrophysical parameters to date, and is based uniquely on Gaia data. It will only be superseded by Gaia Data Release 4, and will therefore remain a key reference over the next four years, providing astrophysical parameters independent of other ground

Published
2023
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3. Gaia Data Release 3 : Analysis of the Gaia BP/RP spectra using the General Stellar Parameterizer from Photometry

Author

Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The astrophysical characterisation of sources is among the major new data products in the third Gaia Data Release (DR3). In particular, there are stellar parameters for 471 million sources estimated from low-resolution BP /RP spectra. Aims: We present the General Stellar Parameterizer from Photometry (GSP-Phot), which is part of the astrophysical parameters inference system (Apsis). GSP-Phot is designed to produce a homogeneous catalogue of parameters for hundreds of millions of single non-variable stars based on their astrometry, photometry, and low-resolution BP/RP spectra. These parameters are effective temperature, surface gravity, metallicity, absolute MG magnitude, radius, distance, and extinction for each star. Methods: GSP-Phot uses a Bayesian forward-modelling approach to simultaneously fit the BP /RP spectrum, parallax, and apparent G magnitude. A major design feature of GSP-Phot is the use of the apparent flux levels of BP /RP spectra to derive, in combination with isochrone models, tight observational constraints on radii and distances. We carefully validate the uncertainty estimates by exploiting repeat Gaia observations of the same source. Results: The data release includes GSP-Phot results for 471 million sources with G < 19. Typical differences to literature values are 110K for T-eff and 0.2-0.25 for log g, but these depend strongly on data quality. In particular, GSP-Phot results are significantly better for stars with good parallax measurements (pi/sigma(pi) > 20), mostly within 2 kpc. Metallicity estimates exhibit substantial biases compared to literature values and are only useful at a qualitative level. However, we provide an empirical calibration of our metallicity estimates that largely removes these biases. Extinctions A(0) and A(BP) show typical di fferences from reference values of 0.07-0.09 mag. MCMC samples of the parameters are also available for 95% of the sources. Conclusions: GSP-Phot provides a homogeneous catalogue of

Published
2023
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4. Gaia Data Release 3 : Analysis of RVS spectra using the General Stellar Parametriser from spectroscopy

Author

Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., Bakker, J., Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., and Bakker, J.

Abstract

Context: The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. A worldwide observational effort from the ground has provided, in one century, an extremely heterogeneous collection of chemical abundances for about two million stars in total, with fragmentary sky coverage. Aims: This situation is revolutionised by the Gaia third data release (DR3), which contains the parametrisation of Radial Velocity Spectrometer (RVS) data performed by the General Stellar Parametriser-spectroscopy, GSP-Spec, module. Here we describe the parametrisation of the first 34 months of Gaia RVS observations. Methods: GSP-Spec estimates the chemo-physical parameters from combined RVS spectra of single stars, without additional inputs from astrometric, photometric, or spectro-photometric BP /RP data. The main analysis workflow described here, MatisseGauguin, is based on projection and optimisation methods and provides the stellar atmospheric parameters; the individual chemical abundances of N, Mg, Si, S, Ca, Ti, Cr, Fe i, Fe ii, Ni, Zr, Ce and Nd; the di fferential equivalent width of a cyanogen line; and the parameters of a di ffuse interstellar band (DIB) feature. Another workflow, based on an artificial neural network (ANN) and referred to with the same acronym, provides a second set of atmospheric parameters that are useful for classification control. For both workflows, we implement a detailed quality flag chain considering different error sources. Results: With about 5.6 million stars, the Gaia DR3 GSP-Spec all-sky catalogue is the largest compilation of stellar chemo-physical parameters ever published and the first one from space data. Internal and external biases have been studied taking into account the implemented flags. In some cases, simple calibrations with low degree polynomials are suggested. The homogeneity and quality of the estimated parameters enables chemo-dynamical studie

Published
2023
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5. Gaia Data Release 3 : Stellar chromospheric activity and mass accretion from Ca II IRT observed by the Radial Velocity Spectrometer

Author

Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (lambda/Delta lambda similar to 11 500) in the near-infrared (845 872 nm). This wavelength range includes the Ca ii infrared triplet (IRT) at 850.03, 854.44, and 866.45 nm, which is a good indicator of magnetic activity in the chromosphere of late-type stars. Aims: Here we present the method devised for inferring the Gaia stellar activity index from the analysis of the Ca ii IRT in the RVS spectrum, together with its scientific validation. Methods: The Gaia stellar activity index is derived from the Ca ii IRT excess equivalent width with respect to a reference spectrum, taking the projected rotational velocity (v sin i) into account. We performed scientific validation of the Gaia stellar activity index by deriving a R'(IRT) index, which is largely independent of the photospheric parameters, and considering the correlation with the R'(HK) index for a sample of stars. A sample of well-studied pre-main-sequence (PMS) stars is considered to identify the regime in which the Gaia stellar activity index may be a ffected by mass accretion. The position of these stars in the colour-magnitude diagram and the correlation with the amplitude of the photometric rotational modulation is also scrutinised. Results: Gaia DR3 contains a stellar activity index derived from the Ca ii IRT for some 2 x 10(6) stars in the Galaxy. This represents a `gold mine' for studies on stellar magnetic activity and mass accretion in the solar vicinity. Three regimes of the chromospheric stellar activity are identified, confirming suggestions made by previous authors based on much smaller R-HK(') datasets. The highest stellar activity regime is associated with PMS stars and RS CVn systems, in which activity is enhanced by tidal interaction. Some evidence of a bimodal distribution in main sequence (MS) stars with T-eff >= 5000K is also found, which

Published
2023
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6. Gaia Data Release 3 : Analysis of RVS spectra using the General Stellar Parametriser from spectroscopy

Author

Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., Bakker, J., Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., and Bakker, J.

Abstract

Context: The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. A worldwide observational effort from the ground has provided, in one century, an extremely heterogeneous collection of chemical abundances for about two million stars in total, with fragmentary sky coverage. Aims: This situation is revolutionised by the Gaia third data release (DR3), which contains the parametrisation of Radial Velocity Spectrometer (RVS) data performed by the General Stellar Parametriser-spectroscopy, GSP-Spec, module. Here we describe the parametrisation of the first 34 months of Gaia RVS observations. Methods: GSP-Spec estimates the chemo-physical parameters from combined RVS spectra of single stars, without additional inputs from astrometric, photometric, or spectro-photometric BP /RP data. The main analysis workflow described here, MatisseGauguin, is based on projection and optimisation methods and provides the stellar atmospheric parameters; the individual chemical abundances of N, Mg, Si, S, Ca, Ti, Cr, Fe i, Fe ii, Ni, Zr, Ce and Nd; the di fferential equivalent width of a cyanogen line; and the parameters of a di ffuse interstellar band (DIB) feature. Another workflow, based on an artificial neural network (ANN) and referred to with the same acronym, provides a second set of atmospheric parameters that are useful for classification control. For both workflows, we implement a detailed quality flag chain considering different error sources. Results: With about 5.6 million stars, the Gaia DR3 GSP-Spec all-sky catalogue is the largest compilation of stellar chemo-physical parameters ever published and the first one from space data. Internal and external biases have been studied taking into account the implemented flags. In some cases, simple calibrations with low degree polynomials are suggested. The homogeneity and quality of the estimated parameters enables chemo-dynamical studie

Published
2023
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7. Gaia Data Release 3 : Astrophysical parameters inference system (Apsis). I. Methods and content overview

Author

Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., Silvester, J., Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., and Silvester, J.

Abstract

Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are a major component of this release, and were produced by the Astrophysical parameters inference system (Apsis) within the Gaia Data Processing and Analysis Consortium (DPAC). The aim of this paper is to describe the overall content of the astrophysical parameters in Gaia DR3 and how they were produced. In Apsis, we use the mean BP /RP and mean RVS spectra along with astrometry and photometry, and we derive the following parameters: source classification and probabilities for 1.6 billion objects; interstellar medium characterisation and distances for up to 470 million sources, including a 2D total Galactic extinction map; 6 million redshifts of quasar candidates; 1.4 million redshifts of galaxy candidates; and an analysis of 50 million outlier sources through an unsupervised classification. The astrophysical parameters also include many stellar spectroscopic and evolutionary parameters for up to 470 million sources. These comprise T-eff, log g, and [M /H] (470 million using BP /RP, 6 million using RVS), radius (470 million), mass (140 million), age (120 million), chemical abundances (up to 5 million), diffuse interstellar band analysis (0.5 million), activity indices (2 million), H ff equivalent widths (200 million), and further classification of spectral types (220 million) and emission-line stars (50 000). This paper is the first in a series of three papers, and focusses on describing the global content of the parameters in Gaia DR3. The accompanying Papers II and III focus on the validation and use of the stellar and non-stellar products, respectively. This catalogue is the most extensive homogeneous database of astrophysical parameters to date, and is based uniquely on Gaia data. It will only be superseded by Gaia Data Release 4, and will therefore remain a key reference over the next four years, providing astrophysical parameters independent of other ground

Published
2023
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8. Gaia Data Release 3 : Analysis of the Gaia BP/RP spectra using the General Stellar Parameterizer from Photometry

Author

Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The astrophysical characterisation of sources is among the major new data products in the third Gaia Data Release (DR3). In particular, there are stellar parameters for 471 million sources estimated from low-resolution BP /RP spectra. Aims: We present the General Stellar Parameterizer from Photometry (GSP-Phot), which is part of the astrophysical parameters inference system (Apsis). GSP-Phot is designed to produce a homogeneous catalogue of parameters for hundreds of millions of single non-variable stars based on their astrometry, photometry, and low-resolution BP/RP spectra. These parameters are effective temperature, surface gravity, metallicity, absolute MG magnitude, radius, distance, and extinction for each star. Methods: GSP-Phot uses a Bayesian forward-modelling approach to simultaneously fit the BP /RP spectrum, parallax, and apparent G magnitude. A major design feature of GSP-Phot is the use of the apparent flux levels of BP /RP spectra to derive, in combination with isochrone models, tight observational constraints on radii and distances. We carefully validate the uncertainty estimates by exploiting repeat Gaia observations of the same source. Results: The data release includes GSP-Phot results for 471 million sources with G < 19. Typical differences to literature values are 110K for T-eff and 0.2-0.25 for log g, but these depend strongly on data quality. In particular, GSP-Phot results are significantly better for stars with good parallax measurements (pi/sigma(pi) > 20), mostly within 2 kpc. Metallicity estimates exhibit substantial biases compared to literature values and are only useful at a qualitative level. However, we provide an empirical calibration of our metallicity estimates that largely removes these biases. Extinctions A(0) and A(BP) show typical di fferences from reference values of 0.07-0.09 mag. MCMC samples of the parameters are also available for 95% of the sources. Conclusions: GSP-Phot provides a homogeneous catalogue of

Published
2023
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9. Apsis. III. Non-stellar content and source classification

Author

Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: As part of the third Gaia Data Release, we present the contributions of the non-stellar and classification modules from the eighth coordination unit (CU8) of the Data Processing and Analysis Consortium, which is responsible for the determination of source astrophysical parameters using Gaia data. This is the third in a series of three papers describing the work done within CU8 for this release. Aims: For each of the five relevant modules from CU8, we summarise their objectives, the methods they employ, their performance, and the results they produce for Gaia DR3. We further advise how to use these data products and highlight some limitations. Methods: The Discrete Source Classifier (DSC) module provides classification probabilities associated with five types of sources: quasars, galaxies, stars, white dwarfs, and physical binary stars. A subset of these sources are processed by the Outlier Analysis (OA) module, which performs an unsupervised clustering analysis, and then associates labels with the clusters to complement the DSC classification. The Quasi Stellar Object Classifier (QSOC) and the Unresolved Galaxy Classifier (UGC) determine the redshifts of the sources classified as quasar and galaxy by the DSC module. Finally, the Total Galactic Extinction (TGE) module uses the extinctions of individual stars determined by another CU8 module to determine the asymptotic extinction along all lines of sight for Galactic latitudes |b| > 5 degrees. Results: Gaia DR3 includes 1591 million sources with DSC classifications; 56 million sources to which the OA clustering is applied; 1.4 million sources with redshift estimates from UGC; 6.4 million sources with QSOC redshift; and 3.1 million level 9 HEALPixes of size 0 :013 deg(2) where the extinction is evaluated by TGE. Conclusions: Validation shows that results are in good agreement with values from external catalogues; for example 90% of the QSOC redshifts have absolute error lower than 0:1 for sources with empty

Published
2023
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10. Gaia Data Release 3 : Stellar chromospheric activity and mass accretion from Ca II IRT observed by the Radial Velocity Spectrometer

Author

Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (lambda/Delta lambda similar to 11 500) in the near-infrared (845 872 nm). This wavelength range includes the Ca ii infrared triplet (IRT) at 850.03, 854.44, and 866.45 nm, which is a good indicator of magnetic activity in the chromosphere of late-type stars. Aims: Here we present the method devised for inferring the Gaia stellar activity index from the analysis of the Ca ii IRT in the RVS spectrum, together with its scientific validation. Methods: The Gaia stellar activity index is derived from the Ca ii IRT excess equivalent width with respect to a reference spectrum, taking the projected rotational velocity (v sin i) into account. We performed scientific validation of the Gaia stellar activity index by deriving a R'(IRT) index, which is largely independent of the photospheric parameters, and considering the correlation with the R'(HK) index for a sample of stars. A sample of well-studied pre-main-sequence (PMS) stars is considered to identify the regime in which the Gaia stellar activity index may be a ffected by mass accretion. The position of these stars in the colour-magnitude diagram and the correlation with the amplitude of the photometric rotational modulation is also scrutinised. Results: Gaia DR3 contains a stellar activity index derived from the Ca ii IRT for some 2 x 10(6) stars in the Galaxy. This represents a `gold mine' for studies on stellar magnetic activity and mass accretion in the solar vicinity. Three regimes of the chromospheric stellar activity are identified, confirming suggestions made by previous authors based on much smaller R-HK(') datasets. The highest stellar activity regime is associated with PMS stars and RS CVn systems, in which activity is enhanced by tidal interaction. Some evidence of a bimodal distribution in main sequence (MS) stars with T-eff >= 5000K is also found, which

Published
2023
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11. Gaia Data Release 3 : Astrophysical parameters inference system (Apsis). I. Methods and content overview

Author

Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., Silvester, J., Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., and Silvester, J.

Abstract

Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are a major component of this release, and were produced by the Astrophysical parameters inference system (Apsis) within the Gaia Data Processing and Analysis Consortium (DPAC). The aim of this paper is to describe the overall content of the astrophysical parameters in Gaia DR3 and how they were produced. In Apsis, we use the mean BP /RP and mean RVS spectra along with astrometry and photometry, and we derive the following parameters: source classification and probabilities for 1.6 billion objects; interstellar medium characterisation and distances for up to 470 million sources, including a 2D total Galactic extinction map; 6 million redshifts of quasar candidates; 1.4 million redshifts of galaxy candidates; and an analysis of 50 million outlier sources through an unsupervised classification. The astrophysical parameters also include many stellar spectroscopic and evolutionary parameters for up to 470 million sources. These comprise T-eff, log g, and [M /H] (470 million using BP /RP, 6 million using RVS), radius (470 million), mass (140 million), age (120 million), chemical abundances (up to 5 million), diffuse interstellar band analysis (0.5 million), activity indices (2 million), H ff equivalent widths (200 million), and further classification of spectral types (220 million) and emission-line stars (50 000). This paper is the first in a series of three papers, and focusses on describing the global content of the parameters in Gaia DR3. The accompanying Papers II and III focus on the validation and use of the stellar and non-stellar products, respectively. This catalogue is the most extensive homogeneous database of astrophysical parameters to date, and is based uniquely on Gaia data. It will only be superseded by Gaia Data Release 4, and will therefore remain a key reference over the next four years, providing astrophysical parameters independent of other ground

Published
2023
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12. Gaia Data Release 3 : Analysis of the Gaia BP/RP spectra using the General Stellar Parameterizer from Photometry

Author

Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The astrophysical characterisation of sources is among the major new data products in the third Gaia Data Release (DR3). In particular, there are stellar parameters for 471 million sources estimated from low-resolution BP /RP spectra. Aims: We present the General Stellar Parameterizer from Photometry (GSP-Phot), which is part of the astrophysical parameters inference system (Apsis). GSP-Phot is designed to produce a homogeneous catalogue of parameters for hundreds of millions of single non-variable stars based on their astrometry, photometry, and low-resolution BP/RP spectra. These parameters are effective temperature, surface gravity, metallicity, absolute MG magnitude, radius, distance, and extinction for each star. Methods: GSP-Phot uses a Bayesian forward-modelling approach to simultaneously fit the BP /RP spectrum, parallax, and apparent G magnitude. A major design feature of GSP-Phot is the use of the apparent flux levels of BP /RP spectra to derive, in combination with isochrone models, tight observational constraints on radii and distances. We carefully validate the uncertainty estimates by exploiting repeat Gaia observations of the same source. Results: The data release includes GSP-Phot results for 471 million sources with G < 19. Typical differences to literature values are 110K for T-eff and 0.2-0.25 for log g, but these depend strongly on data quality. In particular, GSP-Phot results are significantly better for stars with good parallax measurements (pi/sigma(pi) > 20), mostly within 2 kpc. Metallicity estimates exhibit substantial biases compared to literature values and are only useful at a qualitative level. However, we provide an empirical calibration of our metallicity estimates that largely removes these biases. Extinctions A(0) and A(BP) show typical di fferences from reference values of 0.07-0.09 mag. MCMC samples of the parameters are also available for 95% of the sources. Conclusions: GSP-Phot provides a homogeneous catalogue of

Published
2023
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13. Gaia Data Release 3 : Analysis of RVS spectra using the General Stellar Parametriser from spectroscopy

Author

Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., Bakker, J., Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., and Bakker, J.

Abstract

Context: The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. A worldwide observational effort from the ground has provided, in one century, an extremely heterogeneous collection of chemical abundances for about two million stars in total, with fragmentary sky coverage. Aims: This situation is revolutionised by the Gaia third data release (DR3), which contains the parametrisation of Radial Velocity Spectrometer (RVS) data performed by the General Stellar Parametriser-spectroscopy, GSP-Spec, module. Here we describe the parametrisation of the first 34 months of Gaia RVS observations. Methods: GSP-Spec estimates the chemo-physical parameters from combined RVS spectra of single stars, without additional inputs from astrometric, photometric, or spectro-photometric BP /RP data. The main analysis workflow described here, MatisseGauguin, is based on projection and optimisation methods and provides the stellar atmospheric parameters; the individual chemical abundances of N, Mg, Si, S, Ca, Ti, Cr, Fe i, Fe ii, Ni, Zr, Ce and Nd; the di fferential equivalent width of a cyanogen line; and the parameters of a di ffuse interstellar band (DIB) feature. Another workflow, based on an artificial neural network (ANN) and referred to with the same acronym, provides a second set of atmospheric parameters that are useful for classification control. For both workflows, we implement a detailed quality flag chain considering different error sources. Results: With about 5.6 million stars, the Gaia DR3 GSP-Spec all-sky catalogue is the largest compilation of stellar chemo-physical parameters ever published and the first one from space data. Internal and external biases have been studied taking into account the implemented flags. In some cases, simple calibrations with low degree polynomials are suggested. The homogeneity and quality of the estimated parameters enables chemo-dynamical studie

Published
2023
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14. Apsis. III. Non-stellar content and source classification

Author

Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: As part of the third Gaia Data Release, we present the contributions of the non-stellar and classification modules from the eighth coordination unit (CU8) of the Data Processing and Analysis Consortium, which is responsible for the determination of source astrophysical parameters using Gaia data. This is the third in a series of three papers describing the work done within CU8 for this release. Aims: For each of the five relevant modules from CU8, we summarise their objectives, the methods they employ, their performance, and the results they produce for Gaia DR3. We further advise how to use these data products and highlight some limitations. Methods: The Discrete Source Classifier (DSC) module provides classification probabilities associated with five types of sources: quasars, galaxies, stars, white dwarfs, and physical binary stars. A subset of these sources are processed by the Outlier Analysis (OA) module, which performs an unsupervised clustering analysis, and then associates labels with the clusters to complement the DSC classification. The Quasi Stellar Object Classifier (QSOC) and the Unresolved Galaxy Classifier (UGC) determine the redshifts of the sources classified as quasar and galaxy by the DSC module. Finally, the Total Galactic Extinction (TGE) module uses the extinctions of individual stars determined by another CU8 module to determine the asymptotic extinction along all lines of sight for Galactic latitudes |b| > 5 degrees. Results: Gaia DR3 includes 1591 million sources with DSC classifications; 56 million sources to which the OA clustering is applied; 1.4 million sources with redshift estimates from UGC; 6.4 million sources with QSOC redshift; and 3.1 million level 9 HEALPixes of size 0 :013 deg(2) where the extinction is evaluated by TGE. Conclusions: Validation shows that results are in good agreement with values from external catalogues; for example 90% of the QSOC redshifts have absolute error lower than 0:1 for sources with empty

Published
2023
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15. Gaia Data Release 3 : Stellar chromospheric activity and mass accretion from Ca II IRT observed by the Radial Velocity Spectrometer

Author

Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (lambda/Delta lambda similar to 11 500) in the near-infrared (845 872 nm). This wavelength range includes the Ca ii infrared triplet (IRT) at 850.03, 854.44, and 866.45 nm, which is a good indicator of magnetic activity in the chromosphere of late-type stars. Aims: Here we present the method devised for inferring the Gaia stellar activity index from the analysis of the Ca ii IRT in the RVS spectrum, together with its scientific validation. Methods: The Gaia stellar activity index is derived from the Ca ii IRT excess equivalent width with respect to a reference spectrum, taking the projected rotational velocity (v sin i) into account. We performed scientific validation of the Gaia stellar activity index by deriving a R'(IRT) index, which is largely independent of the photospheric parameters, and considering the correlation with the R'(HK) index for a sample of stars. A sample of well-studied pre-main-sequence (PMS) stars is considered to identify the regime in which the Gaia stellar activity index may be a ffected by mass accretion. The position of these stars in the colour-magnitude diagram and the correlation with the amplitude of the photometric rotational modulation is also scrutinised. Results: Gaia DR3 contains a stellar activity index derived from the Ca ii IRT for some 2 x 10(6) stars in the Galaxy. This represents a `gold mine' for studies on stellar magnetic activity and mass accretion in the solar vicinity. Three regimes of the chromospheric stellar activity are identified, confirming suggestions made by previous authors based on much smaller R-HK(') datasets. The highest stellar activity regime is associated with PMS stars and RS CVn systems, in which activity is enhanced by tidal interaction. Some evidence of a bimodal distribution in main sequence (MS) stars with T-eff >= 5000K is also found, which

Published
2023
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16. Gaia Data Release 3 : Analysis of RVS spectra using the General Stellar Parametriser from spectroscopy

Author

Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., Bakker, J., Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., and Bakker, J.

Abstract

Context: The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. A worldwide observational effort from the ground has provided, in one century, an extremely heterogeneous collection of chemical abundances for about two million stars in total, with fragmentary sky coverage. Aims: This situation is revolutionised by the Gaia third data release (DR3), which contains the parametrisation of Radial Velocity Spectrometer (RVS) data performed by the General Stellar Parametriser-spectroscopy, GSP-Spec, module. Here we describe the parametrisation of the first 34 months of Gaia RVS observations. Methods: GSP-Spec estimates the chemo-physical parameters from combined RVS spectra of single stars, without additional inputs from astrometric, photometric, or spectro-photometric BP /RP data. The main analysis workflow described here, MatisseGauguin, is based on projection and optimisation methods and provides the stellar atmospheric parameters; the individual chemical abundances of N, Mg, Si, S, Ca, Ti, Cr, Fe i, Fe ii, Ni, Zr, Ce and Nd; the di fferential equivalent width of a cyanogen line; and the parameters of a di ffuse interstellar band (DIB) feature. Another workflow, based on an artificial neural network (ANN) and referred to with the same acronym, provides a second set of atmospheric parameters that are useful for classification control. For both workflows, we implement a detailed quality flag chain considering different error sources. Results: With about 5.6 million stars, the Gaia DR3 GSP-Spec all-sky catalogue is the largest compilation of stellar chemo-physical parameters ever published and the first one from space data. Internal and external biases have been studied taking into account the implemented flags. In some cases, simple calibrations with low degree polynomials are suggested. The homogeneity and quality of the estimated parameters enables chemo-dynamical studie

Published
2023
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17. Gaia Data Release 3 : Astrophysical parameters inference system (Apsis). I. Methods and content overview

Author

Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., Silvester, J., Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., and Silvester, J.

Abstract

Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are a major component of this release, and were produced by the Astrophysical parameters inference system (Apsis) within the Gaia Data Processing and Analysis Consortium (DPAC). The aim of this paper is to describe the overall content of the astrophysical parameters in Gaia DR3 and how they were produced. In Apsis, we use the mean BP /RP and mean RVS spectra along with astrometry and photometry, and we derive the following parameters: source classification and probabilities for 1.6 billion objects; interstellar medium characterisation and distances for up to 470 million sources, including a 2D total Galactic extinction map; 6 million redshifts of quasar candidates; 1.4 million redshifts of galaxy candidates; and an analysis of 50 million outlier sources through an unsupervised classification. The astrophysical parameters also include many stellar spectroscopic and evolutionary parameters for up to 470 million sources. These comprise T-eff, log g, and [M /H] (470 million using BP /RP, 6 million using RVS), radius (470 million), mass (140 million), age (120 million), chemical abundances (up to 5 million), diffuse interstellar band analysis (0.5 million), activity indices (2 million), H ff equivalent widths (200 million), and further classification of spectral types (220 million) and emission-line stars (50 000). This paper is the first in a series of three papers, and focusses on describing the global content of the parameters in Gaia DR3. The accompanying Papers II and III focus on the validation and use of the stellar and non-stellar products, respectively. This catalogue is the most extensive homogeneous database of astrophysical parameters to date, and is based uniquely on Gaia data. It will only be superseded by Gaia Data Release 4, and will therefore remain a key reference over the next four years, providing astrophysical parameters independent of other ground

Published
2023
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18. Gaia Data Release 3 : Analysis of the Gaia BP/RP spectra using the General Stellar Parameterizer from Photometry

Author

Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The astrophysical characterisation of sources is among the major new data products in the third Gaia Data Release (DR3). In particular, there are stellar parameters for 471 million sources estimated from low-resolution BP /RP spectra. Aims: We present the General Stellar Parameterizer from Photometry (GSP-Phot), which is part of the astrophysical parameters inference system (Apsis). GSP-Phot is designed to produce a homogeneous catalogue of parameters for hundreds of millions of single non-variable stars based on their astrometry, photometry, and low-resolution BP/RP spectra. These parameters are effective temperature, surface gravity, metallicity, absolute MG magnitude, radius, distance, and extinction for each star. Methods: GSP-Phot uses a Bayesian forward-modelling approach to simultaneously fit the BP /RP spectrum, parallax, and apparent G magnitude. A major design feature of GSP-Phot is the use of the apparent flux levels of BP /RP spectra to derive, in combination with isochrone models, tight observational constraints on radii and distances. We carefully validate the uncertainty estimates by exploiting repeat Gaia observations of the same source. Results: The data release includes GSP-Phot results for 471 million sources with G < 19. Typical differences to literature values are 110K for T-eff and 0.2-0.25 for log g, but these depend strongly on data quality. In particular, GSP-Phot results are significantly better for stars with good parallax measurements (pi/sigma(pi) > 20), mostly within 2 kpc. Metallicity estimates exhibit substantial biases compared to literature values and are only useful at a qualitative level. However, we provide an empirical calibration of our metallicity estimates that largely removes these biases. Extinctions A(0) and A(BP) show typical di fferences from reference values of 0.07-0.09 mag. MCMC samples of the parameters are also available for 95% of the sources. Conclusions: GSP-Phot provides a homogeneous catalogue of

Published
2023
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19. Gaia Data Release 3 : Stellar chromospheric activity and mass accretion from Ca II IRT observed by the Radial Velocity Spectrometer

Author

Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (lambda/Delta lambda similar to 11 500) in the near-infrared (845 872 nm). This wavelength range includes the Ca ii infrared triplet (IRT) at 850.03, 854.44, and 866.45 nm, which is a good indicator of magnetic activity in the chromosphere of late-type stars. Aims: Here we present the method devised for inferring the Gaia stellar activity index from the analysis of the Ca ii IRT in the RVS spectrum, together with its scientific validation. Methods: The Gaia stellar activity index is derived from the Ca ii IRT excess equivalent width with respect to a reference spectrum, taking the projected rotational velocity (v sin i) into account. We performed scientific validation of the Gaia stellar activity index by deriving a R'(IRT) index, which is largely independent of the photospheric parameters, and considering the correlation with the R'(HK) index for a sample of stars. A sample of well-studied pre-main-sequence (PMS) stars is considered to identify the regime in which the Gaia stellar activity index may be a ffected by mass accretion. The position of these stars in the colour-magnitude diagram and the correlation with the amplitude of the photometric rotational modulation is also scrutinised. Results: Gaia DR3 contains a stellar activity index derived from the Ca ii IRT for some 2 x 10(6) stars in the Galaxy. This represents a `gold mine' for studies on stellar magnetic activity and mass accretion in the solar vicinity. Three regimes of the chromospheric stellar activity are identified, confirming suggestions made by previous authors based on much smaller R-HK(') datasets. The highest stellar activity regime is associated with PMS stars and RS CVn systems, in which activity is enhanced by tidal interaction. Some evidence of a bimodal distribution in main sequence (MS) stars with T-eff >= 5000K is also found, which

Published
2023
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20. Apsis. III. Non-stellar content and source classification

Author

Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: As part of the third Gaia Data Release, we present the contributions of the non-stellar and classification modules from the eighth coordination unit (CU8) of the Data Processing and Analysis Consortium, which is responsible for the determination of source astrophysical parameters using Gaia data. This is the third in a series of three papers describing the work done within CU8 for this release. Aims: For each of the five relevant modules from CU8, we summarise their objectives, the methods they employ, their performance, and the results they produce for Gaia DR3. We further advise how to use these data products and highlight some limitations. Methods: The Discrete Source Classifier (DSC) module provides classification probabilities associated with five types of sources: quasars, galaxies, stars, white dwarfs, and physical binary stars. A subset of these sources are processed by the Outlier Analysis (OA) module, which performs an unsupervised clustering analysis, and then associates labels with the clusters to complement the DSC classification. The Quasi Stellar Object Classifier (QSOC) and the Unresolved Galaxy Classifier (UGC) determine the redshifts of the sources classified as quasar and galaxy by the DSC module. Finally, the Total Galactic Extinction (TGE) module uses the extinctions of individual stars determined by another CU8 module to determine the asymptotic extinction along all lines of sight for Galactic latitudes |b| > 5 degrees. Results: Gaia DR3 includes 1591 million sources with DSC classifications; 56 million sources to which the OA clustering is applied; 1.4 million sources with redshift estimates from UGC; 6.4 million sources with QSOC redshift; and 3.1 million level 9 HEALPixes of size 0 :013 deg(2) where the extinction is evaluated by TGE. Conclusions: Validation shows that results are in good agreement with values from external catalogues; for example 90% of the QSOC redshifts have absolute error lower than 0:1 for sources with empty

Published
2023
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21. Gaia Data Release 3 Apsis. II. Stellar parameters

Author

Fouesneau, M., Fremat, Y., Andrae, R., Korn, Andreas, Soubiran, C., Kordopatis, G., Vallenari, A., Heiter, U., Creevey, O. L., Sarro, L. M., de laverny, P., Lanzafame, A. C., Lobel, A., Sordo, R., Rybizki, J., Slezak, I., Alvarez, M. A., Drimmel, R., Garabato, D., Delchambre, L., Bailer-Jones, C. A. L., Hatzidimitriou, D., Lorca, A., Le Fustec, Y., Pailler, F., Mary, N., Robin, C., Utrilla, E., Aramburu, A. Abreu, Bakker, J., Bellas-Velidis, I., Bijaoui, A., Blomme, R., Bouret, J. -C, Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Demouchy, C., Dharmawardena, T. E., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Piccolo, A. Jean-Antoine, Kontizas, M., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Martayan, C., Marshall, D. J., Nicolas, C., Ordenovic, C., Palicio, P. A., Pallas-Quintela, L., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Santovena, R., Schultheis, M. S., Segol, M., Silvelo, A., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., van Dillen, E., Zhao, H., Zorec, J., Fouesneau, M., Fremat, Y., Andrae, R., Korn, Andreas, Soubiran, C., Kordopatis, G., Vallenari, A., Heiter, U., Creevey, O. L., Sarro, L. M., de laverny, P., Lanzafame, A. C., Lobel, A., Sordo, R., Rybizki, J., Slezak, I., Alvarez, M. A., Drimmel, R., Garabato, D., Delchambre, L., Bailer-Jones, C. A. L., Hatzidimitriou, D., Lorca, A., Le Fustec, Y., Pailler, F., Mary, N., Robin, C., Utrilla, E., Aramburu, A. Abreu, Bakker, J., Bellas-Velidis, I., Bijaoui, A., Blomme, R., Bouret, J. -C, Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Demouchy, C., Dharmawardena, T. E., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Piccolo, A. Jean-Antoine, Kontizas, M., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Martayan, C., Marshall, D. J., Nicolas, C., Ordenovic, C., Palicio, P. A., Pallas-Quintela, L., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Santovena, R., Schultheis, M. S., Segol, M., Silvelo, A., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context. The third Gaia data release (Gaia DR3) contains, beyond the astrometry and photometry, dispersed light for hundreds of millions of sources from the Gaia prism spectra (BP and RP) and the spectrograph (RVS). This data release opens a new window on the chemo-dynamical properties of stars in our Galaxy, essential knowledge for understanding the structure, formation, and evolution of the Milky Way. Aims. To provide insight into the physical properties of Milky Way stars, we used these data to produce a uniformly derived all-sky catalogue of stellar astrophysical parameters: atmospheric properties (T-e ff, log g, [M /H], [alpha/Fe], activity index, emission lines, and rotation), 13 chemical abundance estimates, evolution characteristics (radius, age, mass, and bolometric luminosity), distance, and dust extinction. Methods. We developed the astrophysical parameter inference system (Apsis) pipeline to infer astrophysical parameters of Gaia objects by analysing their astrometry, photometry, BP /RP, and RVS spectra. We validate our results against those from other works in the literature, including benchmark stars, interferometry, and asteroseismology. Here we assess the stellar analysis performance from Apsis statistically. Results. We describe the quantities we obtained, including the underlying assumptions and the limitations of our results. We provide guidance and identify regimes in which our parameters should and should not be used. Conclusions. Despite some limitations, this is the most extensive catalogue of uniformly inferred stellar parameters to date. They comprise T-eff, log g, and [M/H] (470 million using BP/RP, 6 million using RVS), radius (470 million), mass (140 million), age (120 million), chemical abundances (5 million), di ffuse interstellar band analysis (half a million), activity indices (2 million), H ff equivalent widths (200 million), and further classifications of spectral types (220 million) and emission-line stars (50 thousand). More preci

Published
2023
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22. Gaia Data Release 3 Apsis. II. Stellar parameters

Author

Fouesneau, M., Fremat, Y., Andrae, R., Korn, Andreas, Soubiran, C., Kordopatis, G., Vallenari, A., Heiter, U., Creevey, O. L., Sarro, L. M., de laverny, P., Lanzafame, A. C., Lobel, A., Sordo, R., Rybizki, J., Slezak, I., Alvarez, M. A., Drimmel, R., Garabato, D., Delchambre, L., Bailer-Jones, C. A. L., Hatzidimitriou, D., Lorca, A., Le Fustec, Y., Pailler, F., Mary, N., Robin, C., Utrilla, E., Aramburu, A. Abreu, Bakker, J., Bellas-Velidis, I., Bijaoui, A., Blomme, R., Bouret, J. -C, Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Demouchy, C., Dharmawardena, T. E., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Piccolo, A. Jean-Antoine, Kontizas, M., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Martayan, C., Marshall, D. J., Nicolas, C., Ordenovic, C., Palicio, P. A., Pallas-Quintela, L., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Santovena, R., Schultheis, M. S., Segol, M., Silvelo, A., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., van Dillen, E., Zhao, H., Zorec, J., Fouesneau, M., Fremat, Y., Andrae, R., Korn, Andreas, Soubiran, C., Kordopatis, G., Vallenari, A., Heiter, U., Creevey, O. L., Sarro, L. M., de laverny, P., Lanzafame, A. C., Lobel, A., Sordo, R., Rybizki, J., Slezak, I., Alvarez, M. A., Drimmel, R., Garabato, D., Delchambre, L., Bailer-Jones, C. A. L., Hatzidimitriou, D., Lorca, A., Le Fustec, Y., Pailler, F., Mary, N., Robin, C., Utrilla, E., Aramburu, A. Abreu, Bakker, J., Bellas-Velidis, I., Bijaoui, A., Blomme, R., Bouret, J. -C, Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Demouchy, C., Dharmawardena, T. E., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Piccolo, A. Jean-Antoine, Kontizas, M., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Martayan, C., Marshall, D. J., Nicolas, C., Ordenovic, C., Palicio, P. A., Pallas-Quintela, L., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Santovena, R., Schultheis, M. S., Segol, M., Silvelo, A., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context. The third Gaia data release (Gaia DR3) contains, beyond the astrometry and photometry, dispersed light for hundreds of millions of sources from the Gaia prism spectra (BP and RP) and the spectrograph (RVS). This data release opens a new window on the chemo-dynamical properties of stars in our Galaxy, essential knowledge for understanding the structure, formation, and evolution of the Milky Way. Aims. To provide insight into the physical properties of Milky Way stars, we used these data to produce a uniformly derived all-sky catalogue of stellar astrophysical parameters: atmospheric properties (T-e ff, log g, [M /H], [alpha/Fe], activity index, emission lines, and rotation), 13 chemical abundance estimates, evolution characteristics (radius, age, mass, and bolometric luminosity), distance, and dust extinction. Methods. We developed the astrophysical parameter inference system (Apsis) pipeline to infer astrophysical parameters of Gaia objects by analysing their astrometry, photometry, BP /RP, and RVS spectra. We validate our results against those from other works in the literature, including benchmark stars, interferometry, and asteroseismology. Here we assess the stellar analysis performance from Apsis statistically. Results. We describe the quantities we obtained, including the underlying assumptions and the limitations of our results. We provide guidance and identify regimes in which our parameters should and should not be used. Conclusions. Despite some limitations, this is the most extensive catalogue of uniformly inferred stellar parameters to date. They comprise T-eff, log g, and [M/H] (470 million using BP/RP, 6 million using RVS), radius (470 million), mass (140 million), age (120 million), chemical abundances (5 million), di ffuse interstellar band analysis (half a million), activity indices (2 million), H ff equivalent widths (200 million), and further classifications of spectral types (220 million) and emission-line stars (50 thousand). More preci

Published
2023
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23. Gaia Data Release 3 : Stellar chromospheric activity and mass accretion from Ca II IRT observed by the Radial Velocity Spectrometer

Author

Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Lanzafame, A. C., Brugaletta, E., Fremat, Y., Sordo, R., Creevey, O. L., Andretta, V., Scandariato, G., Busa, I., Distefano, E., Korn, Andreas, de laverny, P., Recio-Blanco, A., Aramburu, A. Abreu, Alvarez, M. A., Andrae, R., Bailer-Jones, C. A. L., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., Delchambre, L., Demouchy, C., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (lambda/Delta lambda similar to 11 500) in the near-infrared (845 872 nm). This wavelength range includes the Ca ii infrared triplet (IRT) at 850.03, 854.44, and 866.45 nm, which is a good indicator of magnetic activity in the chromosphere of late-type stars. Aims: Here we present the method devised for inferring the Gaia stellar activity index from the analysis of the Ca ii IRT in the RVS spectrum, together with its scientific validation. Methods: The Gaia stellar activity index is derived from the Ca ii IRT excess equivalent width with respect to a reference spectrum, taking the projected rotational velocity (v sin i) into account. We performed scientific validation of the Gaia stellar activity index by deriving a R'(IRT) index, which is largely independent of the photospheric parameters, and considering the correlation with the R'(HK) index for a sample of stars. A sample of well-studied pre-main-sequence (PMS) stars is considered to identify the regime in which the Gaia stellar activity index may be a ffected by mass accretion. The position of these stars in the colour-magnitude diagram and the correlation with the amplitude of the photometric rotational modulation is also scrutinised. Results: Gaia DR3 contains a stellar activity index derived from the Ca ii IRT for some 2 x 10(6) stars in the Galaxy. This represents a `gold mine' for studies on stellar magnetic activity and mass accretion in the solar vicinity. Three regimes of the chromospheric stellar activity are identified, confirming suggestions made by previous authors based on much smaller R-HK(') datasets. The highest stellar activity regime is associated with PMS stars and RS CVn systems, in which activity is enhanced by tidal interaction. Some evidence of a bimodal distribution in main sequence (MS) stars with T-eff >= 5000K is also found, which

Published
2023
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24. Apsis. III. Non-stellar content and source classification

Author

Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Delchambre, L., Bailer-Jones, C. A. L., Bellas-Velidis, I., Drimmel, R., Garabato, D., Carballo, R., Hatzidimitriou, D., Marshall, D. J., Andrae, R., Dafonte, C., Livanou, E., Fouesneau, M., Licata, E. L., Lindstrom, H. E. P., Manteiga, M., Robin, C., Silvelo, A., Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bijaoui, A., Brouillet, N., Brugaletta, E., Burlacu, A., Casamiquela, L., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dapergolas, A., de laverny, P., Demouchy, C., Dharmawardena, T. E., Edvardsson, Bengt, Fremat, Y., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Rybizki, J., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Slezak, I., Smart, R. L., Sordo, R., Soubiran, C., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: As part of the third Gaia Data Release, we present the contributions of the non-stellar and classification modules from the eighth coordination unit (CU8) of the Data Processing and Analysis Consortium, which is responsible for the determination of source astrophysical parameters using Gaia data. This is the third in a series of three papers describing the work done within CU8 for this release. Aims: For each of the five relevant modules from CU8, we summarise their objectives, the methods they employ, their performance, and the results they produce for Gaia DR3. We further advise how to use these data products and highlight some limitations. Methods: The Discrete Source Classifier (DSC) module provides classification probabilities associated with five types of sources: quasars, galaxies, stars, white dwarfs, and physical binary stars. A subset of these sources are processed by the Outlier Analysis (OA) module, which performs an unsupervised clustering analysis, and then associates labels with the clusters to complement the DSC classification. The Quasi Stellar Object Classifier (QSOC) and the Unresolved Galaxy Classifier (UGC) determine the redshifts of the sources classified as quasar and galaxy by the DSC module. Finally, the Total Galactic Extinction (TGE) module uses the extinctions of individual stars determined by another CU8 module to determine the asymptotic extinction along all lines of sight for Galactic latitudes |b| > 5 degrees. Results: Gaia DR3 includes 1591 million sources with DSC classifications; 56 million sources to which the OA clustering is applied; 1.4 million sources with redshift estimates from UGC; 6.4 million sources with QSOC redshift; and 3.1 million level 9 HEALPixes of size 0 :013 deg(2) where the extinction is evaluated by TGE. Conclusions: Validation shows that results are in good agreement with values from external catalogues; for example 90% of the QSOC redshifts have absolute error lower than 0:1 for sources with empty

Published
2023
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25. Gaia Data Release 3 : Analysis of the Gaia BP/RP spectra using the General Stellar Parameterizer from Photometry

Author

Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., Zorec, J., Andrae, R., Fouesneau, M., Sordo, R., Bailer-Jones, C. A. L., Dharmawardena, T. E., Rybizki, J., De Angeli, F., Lindstrom, H. E. P., Marshall, D. J., Drimmel, R., Korn, Andreas, Soubiran, C., Brouillet, N., Casamiquela, L., Rix, H. -W, Aramburu, A. Abreu, Alvarez, M. A., Bakker, J., Bellas-Velidis, I., Bijaoui, A., Brugaletta, E., Burlacu, A., Carballo, R., Chaoul, L., Chiavassa, A., Contursi, G., Cooper, W. J., Creevey, O. L., Dafonte, C., Dapergolas, A., De laverny, P., Delchambre, L., Demouchy, C., Edvardsson, Bengt, Fremat, Y., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Mary, N., Nicolas, C., Ordenovic, C., Pailler, F., Palicio, P. A., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Recio-Blanco, A., Riclet, F., Robin, C., Santovena, R., Sarro, L. M., Schultheis, M. S., Segol, M., Silvelo, A., Slezak, I., Smart, R. L., Suveges, M., Thevenin, F., Elipe, G. Torralba, Ulla, A., Utrilla, E., Vallenari, A., van Dillen, E., Zhao, H., and Zorec, J.

Abstract

Context: The astrophysical characterisation of sources is among the major new data products in the third Gaia Data Release (DR3). In particular, there are stellar parameters for 471 million sources estimated from low-resolution BP /RP spectra. Aims: We present the General Stellar Parameterizer from Photometry (GSP-Phot), which is part of the astrophysical parameters inference system (Apsis). GSP-Phot is designed to produce a homogeneous catalogue of parameters for hundreds of millions of single non-variable stars based on their astrometry, photometry, and low-resolution BP/RP spectra. These parameters are effective temperature, surface gravity, metallicity, absolute MG magnitude, radius, distance, and extinction for each star. Methods: GSP-Phot uses a Bayesian forward-modelling approach to simultaneously fit the BP /RP spectrum, parallax, and apparent G magnitude. A major design feature of GSP-Phot is the use of the apparent flux levels of BP /RP spectra to derive, in combination with isochrone models, tight observational constraints on radii and distances. We carefully validate the uncertainty estimates by exploiting repeat Gaia observations of the same source. Results: The data release includes GSP-Phot results for 471 million sources with G < 19. Typical differences to literature values are 110K for T-eff and 0.2-0.25 for log g, but these depend strongly on data quality. In particular, GSP-Phot results are significantly better for stars with good parallax measurements (pi/sigma(pi) > 20), mostly within 2 kpc. Metallicity estimates exhibit substantial biases compared to literature values and are only useful at a qualitative level. However, we provide an empirical calibration of our metallicity estimates that largely removes these biases. Extinctions A(0) and A(BP) show typical di fferences from reference values of 0.07-0.09 mag. MCMC samples of the parameters are also available for 95% of the sources. Conclusions: GSP-Phot provides a homogeneous catalogue of

Published
2023
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26. Gaia Data Release 3 : Astrophysical parameters inference system (Apsis). I. Methods and content overview

Author

Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., Silvester, J., Creevey, O. L., Sordo, R., Pailler, F., Fremat, Y., Heiter, Ulrike, Thevenin, F., Andrae, R., Fouesneau, M., Lobel, A., Bailer-Jones, C. A. L., Garabato, D., Bellas-Velidis, I., Brugaletta, E., Lorca, A., Ordenovic, C., Palicio, P. A., Sarro, L. M., Delchambre, L., Drimmel, R., Rybizki, J., Elipe, G. Torralba, Korn, Andreas, Recio-Blanco, A., Schultheis, M. S., De Angeli, F., Montegri, P., Aramburu, A. Abreu, Accart, S., Alvarez, M. A., Bakker, J., Brouillet, N., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Contursi, G., Cooper, W. J., Dafonte, C., Dapergolas, A., de Laverny, P., Dharmawardena, T. E., Edvardsson, Bengt, Le Fustec, Y., Garcia-Lario, P., Garcia-Torres, M., Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Piccolo, A. Jean-Antoine, Kontiza, M., Kordopatis, G., Lanzafame, A. C., Lebreton, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Romeo, A. Magdaleno, Manteiga, M., Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Poggio, E., Riclet, F., Robin, C., Santovena, R., Silvelo, A., Slezak, I., Smart, R. L., Soubiran, C., Suveges, M., Ulla, A., Utrilla, E., Vallenari, A., Zhao, H., Zorec, J., Barrado, D., Bijaoui, A., Bouret, J. -C, Blomme, R., Brott, I., Cassisi, S., Kochukhov, Oleg, Martayan, C., Shulyak, D., and Silvester, J.

Abstract

Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are a major component of this release, and were produced by the Astrophysical parameters inference system (Apsis) within the Gaia Data Processing and Analysis Consortium (DPAC). The aim of this paper is to describe the overall content of the astrophysical parameters in Gaia DR3 and how they were produced. In Apsis, we use the mean BP /RP and mean RVS spectra along with astrometry and photometry, and we derive the following parameters: source classification and probabilities for 1.6 billion objects; interstellar medium characterisation and distances for up to 470 million sources, including a 2D total Galactic extinction map; 6 million redshifts of quasar candidates; 1.4 million redshifts of galaxy candidates; and an analysis of 50 million outlier sources through an unsupervised classification. The astrophysical parameters also include many stellar spectroscopic and evolutionary parameters for up to 470 million sources. These comprise T-eff, log g, and [M /H] (470 million using BP /RP, 6 million using RVS), radius (470 million), mass (140 million), age (120 million), chemical abundances (up to 5 million), diffuse interstellar band analysis (0.5 million), activity indices (2 million), H ff equivalent widths (200 million), and further classification of spectral types (220 million) and emission-line stars (50 000). This paper is the first in a series of three papers, and focusses on describing the global content of the parameters in Gaia DR3. The accompanying Papers II and III focus on the validation and use of the stellar and non-stellar products, respectively. This catalogue is the most extensive homogeneous database of astrophysical parameters to date, and is based uniquely on Gaia data. It will only be superseded by Gaia Data Release 4, and will therefore remain a key reference over the next four years, providing astrophysical parameters independent of other ground

Published
2023
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27. Gaia Data Release 3 : Analysis of RVS spectra using the General Stellar Parametriser from spectroscopy

Author

Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., Bakker, J., Recio-Blanco, A., De laverny, P., Palicio, P. A., Kordopatis, G., Alvarez, M. A., Schultheis, M., Contursi, G., Zhao, H., Elipe, G. Torralba, Ordenovic, C., Manteiga, M., Dafonte, C., Oreshina-Slezak, I., Bijaoui, A., Fremat, Y., Seabroke, G., Pailler, F., Spitoni, E., Poggio, E., Creevey, O. L., Aramburu, A. Abreu, Accart, S., Andrae, R., Bailer-Jones, C. A. L., Bellas-Velidis, I., Brouillet, N., Brugaletta, E., Burlacu, A., Carballo, R., Casamiquela, L., Chiavassa, A., Cooper, W. J., Dapergolas, A., Delchambre, L., Dharmawardena, T. E., Drimmel, R., Edvardsson, Bengt, Fouesneau, M., Garabato, D., Garcia-Lario, P., Garcia-Torres, M., Gavel, Alvin, Gomez, A., Gonzalez-Santamaria, I., Hatzidimitriou, D., Heiter, Ulrike, Piccolo, A. Jean-Antoine, Kontizas, M., Korn, Andreas, Lanzafame, A. C., Lebreton, Y., Le Fustec, Y., Licata, E. L., Lindstrom, H. E. P., Livanou, E., Lobel, A., Lorca, A., Romeo, A. Magdaleno, Marocco, F., Marshall, D. J., Mary, N., Nicolas, C., Pallas-Quintela, L., Panem, C., Pichon, B., Riclet, F., Robin, C., Rybizki, J., Santovena, R., Silvelo, A., Smart, R. L., Sarro, L. M., Sordo, R., Soubiran, C., Suveges, M., Ulla, A., Vallenari, A., Zorec, J., Utrilla, E., and Bakker, J.

Abstract

Context: The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. A worldwide observational effort from the ground has provided, in one century, an extremely heterogeneous collection of chemical abundances for about two million stars in total, with fragmentary sky coverage. Aims: This situation is revolutionised by the Gaia third data release (DR3), which contains the parametrisation of Radial Velocity Spectrometer (RVS) data performed by the General Stellar Parametriser-spectroscopy, GSP-Spec, module. Here we describe the parametrisation of the first 34 months of Gaia RVS observations. Methods: GSP-Spec estimates the chemo-physical parameters from combined RVS spectra of single stars, without additional inputs from astrometric, photometric, or spectro-photometric BP /RP data. The main analysis workflow described here, MatisseGauguin, is based on projection and optimisation methods and provides the stellar atmospheric parameters; the individual chemical abundances of N, Mg, Si, S, Ca, Ti, Cr, Fe i, Fe ii, Ni, Zr, Ce and Nd; the di fferential equivalent width of a cyanogen line; and the parameters of a di ffuse interstellar band (DIB) feature. Another workflow, based on an artificial neural network (ANN) and referred to with the same acronym, provides a second set of atmospheric parameters that are useful for classification control. For both workflows, we implement a detailed quality flag chain considering different error sources. Results: With about 5.6 million stars, the Gaia DR3 GSP-Spec all-sky catalogue is the largest compilation of stellar chemo-physical parameters ever published and the first one from space data. Internal and external biases have been studied taking into account the implemented flags. In some cases, simple calibrations with low degree polynomials are suggested. The homogeneity and quality of the estimated parameters enables chemo-dynamical studie

Published
2023
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28. Gaia Data Release 1 Summary of the astrometric, photometric, and survey properties

Author

Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Mignard, F., Drimmel, R., Babusiaux, C., Bailer-Jones, C. A. L., Bastian, U., Biermann, M., Evans, D. W., Eyer, L., Jansen, F., Jordi, C., Katz, D., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., O'Mullane, W., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Siddiqui, H. I., Soubiran, C., Valette, V., van Leeuwen, F., Walton, N. A., Aerts, C., Arenou, F., Cropper, M., Hog, E., Lattanzi, M. G., Grebel, E. K., Holland, A. D., Huc, C., Passot, X., Perryman, M., Bramante, L., Cacciari, C., Castaneda, J., Chaoul, L., Cheek, N., De Angeli, F., Fabricius, C., Guerra, R., Hernandez, J., Jean-Antoine-Piccolo, A., Masana, E., Messineo, R., Mowlavi, N., Nienartowicz, K., Ordonez-Blanco, D., Panuzzo, P., Portell, J., Richards, P. J., Riello, M., Seabroke, G. M., Tanga, P., Thevenin, F., Torra, J., Els, S. G., Gracia-Abril, G., Comoretto, G., Garcia-Reinaldos, M., Lock, T., Mercier, E., Altmann, M., Andrae, R., Astraatmadja, T. L., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Busso, G., Carry, B., Cellino, A., Clementini, G., Cowell, S., Creevey, O., Cuypers, J., Davidson, M., De Ridder, J., de Torres, A., Delchambre, L., Dell'Oro, A., Ducourant, C., Fremat, Y., Garcia-Torres, M., Gosset, E., Halbwachs, J. -L, Hambly, N. C., Harrison, D. L., Hauser, M., Hestroffer, D., Hodgkin, S. T., Huckle, H. E., Hutton, A., Jasniewicz, G., Jordan, S., Kontizas, M., Korn, Andreas J., Lanzafame, A. C., Manteiga, M., Moitinho, A., Muinonen, K., Osinde, J., Pancino, E., Pauwels, T., Petit, J. -M, Recio-Blanco, A., Robin, A. C., Sarro, L. M., Siopis, C., Smith, M., Smith, K. W., Sozzetti, A., Thuillot, W., van Reeven, W., Viala, Y., Abbas, U., Aramburu, A. Abreu, Accart, S., Aguado, J. J., Allan, P. M., Allasia, W., Altavilla, G., Alvarez, M. A., Alves, J., Anderson, R. I., Andrei, A. H., Varela, E. Anglada, Antiche, E., Antoja, T., Anton, S., Arcay, B., Bach, N., Baker, S. G., Balaguer-Nunez, L., Barache, C., Barata, C., Barbier, A., Barblan, F., Barrado y Navascues, D., Barros, M., Barstow, M. A., Becciani, U., Bellazzini, M., Garcia, A. Bello, Belokurov, V., Bendjoya, P., Berihuete, A., Bianchi, L., Bienayme, O., Billebaud, F., Blagorodnova, N., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Borrachero, R., Bouquillon, S., Bourda, G., Bouy, H., Bragaglia, A., Breddels, M. A., Brouillet, N., Bruesemeister, T., Bucciarelli, B., Burgess, P., Burgon, R., Burlacu, A., Busonero, D., Buzzi, R., Caffau, E., Cambras, J., Campbell, H., Cancelliere, R., Cantat-Gaudin, T., Carlucci, T., Carrasco, J. M., Castellani, M., Charlot, P., Charnas, J., Chiavassa, A., Clotet, M., Cocozza, G., Collins, R. S., Costigan, G., Crifo, F., Cross, N. J. G., Crosta, M., Crowley, C., Dafonte, C., Damerdji, Y., Dapergolas, A., David, P., David, M., De Cat, P., de Felice, F., de laverny, P., De Luise, F., De March, R., de Martino, D., de Souza, R., Debosscher, J., del Pozo, E., Delbo, M., Delgado, A., Delgado, H. E., Di Matteo, P., Diakite, S., Distefano, E., Dolding, C., Dos Anjos, S., Drazinos, P., Duran, J., Dzigan, Y., Edvardsson, Bengt, Enke, H., Evans, N. W., Bontemps, G. Eynard, Fabre, C., Fabrizio, M., Faigler, S., Falcao, A. J., Casas, M. Farras, Federici, L., Fedorets, G., Fernandez-Hernandez, J., Fernique, P., Fienga, A., Figueras, F., Filippi, F., Findeisen, K., Fonti, A., Fouesneau, M., Fraile, E., Fraser, M., Fuchs, J., Gai, M., Galleti, S., Galluccio, L., Garabato, D., Garcia-Sedano, F., Garofalo, A., Garralda, N., Gavras, P., Gerssen, J., Geyer, R., Gilmore, G., Girona, S., Giuffrida, G., Gomes, M., Gonzalez-Marcos, A., Gonzalez-Nunez, J., Gonzalez-Vidal, J. J., Granvik, M., Guerrier, A., Guillout, P., Guiraud, J., Gurpide, A., Gutierrez-Sanchez, R., Guy, L. P., Haigron, R., Hatzidimitriou, D., Haywood, M., Heiter, Ulrike, Helmi, A., Hobbs, D., Hofmann, W., Holl, B., Holland, G., Hunt, J. A. S., Hypki, A., Icardi, V., Irwin, M., de Fombelle, G. Jevardat, Jofre, P., Jonker, P. G., Jorissen, A., Julbe, F., Karampelas, A., Kochoska, A., Kohley, R., Kolenberg, K., Kontizas, E., Koposov, S. E., Kordopatis, G., Koubsky, P., Krone-Martins, A., Kudryashova, M., Kull, I., Bachchan, R. K., Lacoste-Seris, F., Lanza, A. F., Lavigne, J. -B, Le Poncin-Lafitte, C., Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Lemaitre, V., Lenhardt, H., Leroux, F., Liao, S., Licata, E., Lindstrom, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Loeffler, W., Lopez, M., Lorenz, D., MacDonald, I., Fernandes, T. Magalhacs, Managau, S., Mann, R. G., Mantelet, G., Marchal, O., Marchant, J. M., Marconi, M., Marinoni, S., Marrese, P. M., Marschalko, G., Marshall, D. J., Martin-Fleitas, J. M., Martino, M., Mary, N., Matijevic, G., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Miranda, B. M. H., Molina, D., Molinaro, R., Molinaro, M., Molnar, L., Moniez, M., Montegriffo, P., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morgenthaler, S., Morris, D., Mulone, A. F., Muraveva, T., Musella, I., Narbonne, J., Nelemans, G., Nicastro, L., Noval, L., Ordenovic, C., Ordieres-Mere, J., Osborne, P., Pagani, C., Pagano, I., Pailler, F., Palacin, H., Palaversa, L., Parsons, P., Pecoraro, M., Pedrosa, R., Pentikainen, H., Pichon, B., Piersimoni, A. M., Pincau, F. -X, Plachy, E., Plum, G., Poujoulet, E., Prsa, A., Pulone, L., Ragaini, S., Rago, S., Rambaux, N., Ramos-Lerate, M., Ranalli, P., Rauw, G., Read, A., Regibo, S., Reyle, C., Ribeiro, R. A., Rimoldini, L., Ripepi, V., Riva, A., Rixon, G., Roelens, M., Romero-Gomez, M., Rowell, N., Royer, F., Ruiz-Dern, L., Sadowski, G., Selles, T. Sagrista, Sahlmann, J., Salgado, J., Salguero, E., Sarasso, M., Savietto, H., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Segransan, D., Shih, I. -C, Smareglia, R., Smart, R. L., Solano, E., Solitro, F., Sordo, R., Nieto, S. Soria, Souchay, J., Spagna, A., Spoto, F., Stampa, U., Steele, I. A., Steidelmueller, H., Stephenson, C. A., Stoev, H., Suess, F. F., Suveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Tapiador, D., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Terrett, D., Tingley, B., Trager, S. C., Turon, C., Ulla, A., Utrilla, E., Valentini, G., van Elteren, A., Van Hemelryck, E., van Leeuwen, M., Varadi, M., Vecchiato, A., Veljanoski, J., Via, T., Vicente, D., Vogt, S., Voss, H., Votruba, V., Voutsinas, S., Walmsley, G., Weiler, M., Weingrill, K., Wevers, T., Wyrzykowski, L., Yoldas, A., Zerjal, M., Zucker, S., Zurbach, C., Zwitter, T., Alecu, A., Allen, M., Prieto, C. Allende, Amorim, A., Anglada-Escude, G., Arsenijevic, V., Azaz, S., Balm, P., Beck, M., Bernstein, H. -H, Bigot, L., Bijaoui, A., Blasco, C., Bonfigli, M., Bono, G., Boudreault, S., Bressan, A., Brown, S., Brunet, P. -M, Bunclark, P., Buonanno, R., Butkevich, A. G., Carret, C., Carrion, C., Chemin, L., Chereau, F., Corcione, L., Darmigny, E., de Boer, K. S., de Teodoro, P., de Zeeuw, P. T., Delle Luche, C., Domingues, C. D., Dubath, P., Fodor, F., Frezouls, B., Fries, A., Fustes, D., Fyfe, D., Gallardo, E., Gallegos, J., Gardiol, D., Gebran, M., Gomboc, A., Gomez, A., Grux, E., Gueguen, A., Heyrovsky, A., Hoar, J., Iannicola, G., Parache, Y. Isasi, Janotto, A. -M, Joliet, E., Jonckheere, A., Keil, R., Kim, D. -W, Klagyivik, P., Klar, J., Knude, J., Kochukhov, Oleg, Kolka, I., Kos, J., Kutka, A., Lainey, V., LeBouquin, D., Liu, C., Loreggia, D., Makarov, V. V., Marseille, M. G., Martayan, C., Martinez-Rubi, O., Massart, B., Meynadier, F., Mignot, S., Munari, U., Nguyen, A. -T, Nordlander, Thomas, Ocvirk, P., O'Flaherty, K. S., Sanz, A. Olias, Ortiz, P., Osorio, J., Oszkiewicz, D., Ouzounis, A., Palmer, M., Park, P., Pasquato, E., Peltzer, C., Peralta, J., Peturaud, F., Pieniluoma, T., Pigozzi, E., Poels, J., Prat, G., Prod'homme, T., Raison, F., Rebordao, J. M., Risquez, D., Rocca-Volmerange, B., Rosen, S., Ruiz-Fuertes, M. I., Russo, F., Sembay, S., Vizcaino, I. Serraller, Short, A., Siebert, A., Silva, H., Sinachopoulos, D., Slezak, E., Soffel, M., Sosnowska, D., Straizys, V., ter Linden, M., Terrell, D., Theil, S., Tiede, C., Troisi, L., Tsalmantza, P., Tur, D., Vaccari, M., Vachier, F., Valles, P., Van Hamme, W., Veltz, L., Virtanen, J., Wallut, J. -M, Wichmann, R., Wilkinson, M. I., Ziaeepour, H., Zschocke, S., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Mignard, F., Drimmel, R., Babusiaux, C., Bailer-Jones, C. A. L., Bastian, U., Biermann, M., Evans, D. W., Eyer, L., Jansen, F., Jordi, C., Katz, D., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., O'Mullane, W., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Siddiqui, H. I., Soubiran, C., Valette, V., van Leeuwen, F., Walton, N. A., Aerts, C., Arenou, F., Cropper, M., Hog, E., Lattanzi, M. G., Grebel, E. K., Holland, A. D., Huc, C., Passot, X., Perryman, M., Bramante, L., Cacciari, C., Castaneda, J., Chaoul, L., Cheek, N., De Angeli, F., Fabricius, C., Guerra, R., Hernandez, J., Jean-Antoine-Piccolo, A., Masana, E., Messineo, R., Mowlavi, N., Nienartowicz, K., Ordonez-Blanco, D., Panuzzo, P., Portell, J., Richards, P. J., Riello, M., Seabroke, G. M., Tanga, P., Thevenin, F., Torra, J., Els, S. G., Gracia-Abril, G., Comoretto, G., Garcia-Reinaldos, M., Lock, T., Mercier, E., Altmann, M., Andrae, R., Astraatmadja, T. L., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Busso, G., Carry, B., Cellino, A., Clementini, G., Cowell, S., Creevey, O., Cuypers, J., Davidson, M., De Ridder, J., de Torres, A., Delchambre, L., Dell'Oro, A., Ducourant, C., Fremat, Y., Garcia-Torres, M., Gosset, E., Halbwachs, J. -L, Hambly, N. C., Harrison, D. L., Hauser, M., Hestroffer, D., Hodgkin, S. T., Huckle, H. E., Hutton, A., Jasniewicz, G., Jordan, S., Kontizas, M., Korn, Andreas J., Lanzafame, A. C., Manteiga, M., Moitinho, A., Muinonen, K., Osinde, J., Pancino, E., Pauwels, T., Petit, J. -M, Recio-Blanco, A., Robin, A. C., Sarro, L. M., Siopis, C., Smith, M., Smith, K. W., Sozzetti, A., Thuillot, W., van Reeven, W., Viala, Y., Abbas, U., Aramburu, A. Abreu, Accart, S., Aguado, J. J., Allan, P. M., Allasia, W., Altavilla, G., Alvarez, M. A., Alves, J., Anderson, R. I., Andrei, A. H., Varela, E. Anglada, Antiche, E., Antoja, T., Anton, S., Arcay, B., Bach, N., Baker, S. G., Balaguer-Nunez, L., Barache, C., Barata, C., Barbier, A., Barblan, F., Barrado y Navascues, D., Barros, M., Barstow, M. A., Becciani, U., Bellazzini, M., Garcia, A. Bello, Belokurov, V., Bendjoya, P., Berihuete, A., Bianchi, L., Bienayme, O., Billebaud, F., Blagorodnova, N., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Borrachero, R., Bouquillon, S., Bourda, G., Bouy, H., Bragaglia, A., Breddels, M. A., Brouillet, N., Bruesemeister, T., Bucciarelli, B., Burgess, P., Burgon, R., Burlacu, A., Busonero, D., Buzzi, R., Caffau, E., Cambras, J., Campbell, H., Cancelliere, R., Cantat-Gaudin, T., Carlucci, T., Carrasco, J. M., Castellani, M., Charlot, P., Charnas, J., Chiavassa, A., Clotet, M., Cocozza, G., Collins, R. S., Costigan, G., Crifo, F., Cross, N. J. G., Crosta, M., Crowley, C., Dafonte, C., Damerdji, Y., Dapergolas, A., David, P., David, M., De Cat, P., de Felice, F., de laverny, P., De Luise, F., De March, R., de Martino, D., de Souza, R., Debosscher, J., del Pozo, E., Delbo, M., Delgado, A., Delgado, H. E., Di Matteo, P., Diakite, S., Distefano, E., Dolding, C., Dos Anjos, S., Drazinos, P., Duran, J., Dzigan, Y., Edvardsson, Bengt, Enke, H., Evans, N. W., Bontemps, G. Eynard, Fabre, C., Fabrizio, M., Faigler, S., Falcao, A. J., Casas, M. Farras, Federici, L., Fedorets, G., Fernandez-Hernandez, J., Fernique, P., Fienga, A., Figueras, F., Filippi, F., Findeisen, K., Fonti, A., Fouesneau, M., Fraile, E., Fraser, M., Fuchs, J., Gai, M., Galleti, S., Galluccio, L., Garabato, D., Garcia-Sedano, F., Garofalo, A., Garralda, N., Gavras, P., Gerssen, J., Geyer, R., Gilmore, G., Girona, S., Giuffrida, G., Gomes, M., Gonzalez-Marcos, A., Gonzalez-Nunez, J., Gonzalez-Vidal, J. J., Granvik, M., Guerrier, A., Guillout, P., Guiraud, J., Gurpide, A., Gutierrez-Sanchez, R., Guy, L. P., Haigron, R., Hatzidimitriou, D., Haywood, M., Heiter, Ulrike, Helmi, A., Hobbs, D., Hofmann, W., Holl, B., Holland, G., Hunt, J. A. S., Hypki, A., Icardi, V., Irwin, M., de Fombelle, G. Jevardat, Jofre, P., Jonker, P. G., Jorissen, A., Julbe, F., Karampelas, A., Kochoska, A., Kohley, R., Kolenberg, K., Kontizas, E., Koposov, S. E., Kordopatis, G., Koubsky, P., Krone-Martins, A., Kudryashova, M., Kull, I., Bachchan, R. K., Lacoste-Seris, F., Lanza, A. F., Lavigne, J. -B, Le Poncin-Lafitte, C., Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Lemaitre, V., Lenhardt, H., Leroux, F., Liao, S., Licata, E., Lindstrom, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Loeffler, W., Lopez, M., Lorenz, D., MacDonald, I., Fernandes, T. Magalhacs, Managau, S., Mann, R. G., Mantelet, G., Marchal, O., Marchant, J. M., Marconi, M., Marinoni, S., Marrese, P. M., Marschalko, G., Marshall, D. J., Martin-Fleitas, J. M., Martino, M., Mary, N., Matijevic, G., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Miranda, B. M. H., Molina, D., Molinaro, R., Molinaro, M., Molnar, L., Moniez, M., Montegriffo, P., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morgenthaler, S., Morris, D., Mulone, A. F., Muraveva, T., Musella, I., Narbonne, J., Nelemans, G., Nicastro, L., Noval, L., Ordenovic, C., Ordieres-Mere, J., Osborne, P., Pagani, C., Pagano, I., Pailler, F., Palacin, H., Palaversa, L., Parsons, P., Pecoraro, M., Pedrosa, R., Pentikainen, H., Pichon, B., Piersimoni, A. M., Pincau, F. -X, Plachy, E., Plum, G., Poujoulet, E., Prsa, A., Pulone, L., Ragaini, S., Rago, S., Rambaux, N., Ramos-Lerate, M., Ranalli, P., Rauw, G., Read, A., Regibo, S., Reyle, C., Ribeiro, R. A., Rimoldini, L., Ripepi, V., Riva, A., Rixon, G., Roelens, M., Romero-Gomez, M., Rowell, N., Royer, F., Ruiz-Dern, L., Sadowski, G., Selles, T. Sagrista, Sahlmann, J., Salgado, J., Salguero, E., Sarasso, M., Savietto, H., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Segransan, D., Shih, I. -C, Smareglia, R., Smart, R. L., Solano, E., Solitro, F., Sordo, R., Nieto, S. Soria, Souchay, J., Spagna, A., Spoto, F., Stampa, U., Steele, I. A., Steidelmueller, H., Stephenson, C. A., Stoev, H., Suess, F. F., Suveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Tapiador, D., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Terrett, D., Tingley, B., Trager, S. C., Turon, C., Ulla, A., Utrilla, E., Valentini, G., van Elteren, A., Van Hemelryck, E., van Leeuwen, M., Varadi, M., Vecchiato, A., Veljanoski, J., Via, T., Vicente, D., Vogt, S., Voss, H., Votruba, V., Voutsinas, S., Walmsley, G., Weiler, M., Weingrill, K., Wevers, T., Wyrzykowski, L., Yoldas, A., Zerjal, M., Zucker, S., Zurbach, C., Zwitter, T., Alecu, A., Allen, M., Prieto, C. Allende, Amorim, A., Anglada-Escude, G., Arsenijevic, V., Azaz, S., Balm, P., Beck, M., Bernstein, H. -H, Bigot, L., Bijaoui, A., Blasco, C., Bonfigli, M., Bono, G., Boudreault, S., Bressan, A., Brown, S., Brunet, P. -M, Bunclark, P., Buonanno, R., Butkevich, A. G., Carret, C., Carrion, C., Chemin, L., Chereau, F., Corcione, L., Darmigny, E., de Boer, K. S., de Teodoro, P., de Zeeuw, P. T., Delle Luche, C., Domingues, C. D., Dubath, P., Fodor, F., Frezouls, B., Fries, A., Fustes, D., Fyfe, D., Gallardo, E., Gallegos, J., Gardiol, D., Gebran, M., Gomboc, A., Gomez, A., Grux, E., Gueguen, A., Heyrovsky, A., Hoar, J., Iannicola, G., Parache, Y. Isasi, Janotto, A. -M, Joliet, E., Jonckheere, A., Keil, R., Kim, D. -W, Klagyivik, P., Klar, J., Knude, J., Kochukhov, Oleg, Kolka, I., Kos, J., Kutka, A., Lainey, V., LeBouquin, D., Liu, C., Loreggia, D., Makarov, V. V., Marseille, M. G., Martayan, C., Martinez-Rubi, O., Massart, B., Meynadier, F., Mignot, S., Munari, U., Nguyen, A. -T, Nordlander, Thomas, Ocvirk, P., O'Flaherty, K. S., Sanz, A. Olias, Ortiz, P., Osorio, J., Oszkiewicz, D., Ouzounis, A., Palmer, M., Park, P., Pasquato, E., Peltzer, C., Peralta, J., Peturaud, F., Pieniluoma, T., Pigozzi, E., Poels, J., Prat, G., Prod'homme, T., Raison, F., Rebordao, J. M., Risquez, D., Rocca-Volmerange, B., Rosen, S., Ruiz-Fuertes, M. I., Russo, F., Sembay, S., Vizcaino, I. Serraller, Short, A., Siebert, A., Silva, H., Sinachopoulos, D., Slezak, E., Soffel, M., Sosnowska, D., Straizys, V., ter Linden, M., Terrell, D., Theil, S., Tiede, C., Troisi, L., Tsalmantza, P., Tur, D., Vaccari, M., Vachier, F., Valles, P., Van Hamme, W., Veltz, L., Virtanen, J., Wallut, J. -M, Wichmann, R., Wilkinson, M. I., Ziaeepour, H., and Zschocke, S.

Abstract

Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues - a realisation of the Tycho-Gaia Astrometric Solution (TGAS) - and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of similar to 3000 Cepheid and RR Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr(-1) for the proper motions. A systematic component of similar to 0.3 mas should be added to the parallax uncertainties. For the subset of similar to 94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr(-1). For the secondary astrometric data set, the typical uncertainty of the positions is similar to 10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to similar to 0.03 mag over the magnitude range 5 to 20.7. Conclusions. Gaia DR1 is an important milestone ahead of the

Published
2016
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29. The Gaia mission

Author

Prusti, T., de Bruijne, J. H. J., Brown, A. G. A., Vallenari, A., Babusiaux, C., Bailer-Jones, C. A. L., Bastian, U., Biermann, M., Evans, D. W., Eyer, L., Jansen, F., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Mignard, F., Milligan, D. J., Panem, C., Poinsignon, V., Pourbaix, D., Randich, S., Sarri, G., Sartoretti, P., Siddiqui, H. I., Soubiran, C., Valette, V., van Leeuwen, F., Walton, N. A., Aerts, C., Arenou, F., Cropper, M., Drimmel, R., Hog, E., Katz, D., Lattanzi, M. G., O'Mullane, W., Grebel, E. K., Holland, A. D., Huc, C., Passot, X., Bramante, L., Cacciari, C., Castaneda, J., Chaoul, L., Cheek, N., De Angeli, F., Fabricius, C., Guerra, R., Hernandez, J., Jean-Antoine-Piccolo, A., Masana, E., Messineo, R., Mowlavi, N., Nienartowicz, K., Ordonez-Blanco, D., Panuzzo, P., Portell, J., Richards, P. J., Riello, M., Seabroke, G. M., Tanga, P., Thevenin, F., Torra, J., Els, S. G., Gracia-Abril, G., Comoretto, G., Garcia-Reinaldos, M., Lock, T., Mercier, E., Altmann, M., Andrae, R., Astraatmadja, T. L., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Busso, G., Carry, B., Cellino, A., Clementini, G., Cowell, S., Creevey, O., Cuypers, J., Davidson, M., De Ridder, J., de Torres, A., Delchambre, L., Dell'Oro, A., Ducourant, C., Fremat, Y., Garcia-Torres, M., Gosset, E., Halbwachs, J. -L, Hambly, N. C., Harrison, D. L., Hauser, M., Hestroffer, D., Hodgkin, S. T., Huckle, H. E., Hutton, A., Jasniewicz, G., Jordan, S., Kontizas, M., Korn, Andreas J., Lanzafame, A. C., Manteiga, M., Moitinho, A., Muinonen, K., Osinde, J., Pancino, E., Pauwels, T., Petit, J. -M, Recio-Blanco, A., Robin, A. C., Sarro, L. M., Siopis, C., Smith, M., Smith, K. W., Sozzetti, A., Thuillot, W., van Reeven, W., Viala, Y., Abbas, U., Aramburu, A. Abreu, Accart, S., Aguado, J. J., Allan, P. M., Allasia, W., Altavilla, G., Alvarez, M. A., Alves, J., Anderson, R. I., Andrei, A. H., Varela, E. Anglada, Antiche, E., Antoja, T., Anton, S., Arcay, B., Atzei, A., Ayache, L., Bach, N., Baker, S. G., Balaguer-Nunez, L., Barache, C., Barata, C., Barbier, A., Barblan, F., Baroni, M., Barrado y Navascues, D., Barros, M., Barstow, M. A., Becciani, U., Bellazzini, M., Bellei, G., Garcia, A. Bello, Belokurov, V., Bendjoya, P., Berihuete, A., Bianchi, L., Bienayme, O., Billebaud, F., Blagorodnova, N., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Borrachero, R., Bouquillon, S., Bourda, G., Bouy, H., Bragaglia, A., Breddels, M. A., Brouillet, N., Bruesemeister, T., Bucciarelli, B., Budnik, F., Burgess, P., Burgon, R., Burlacu, A., Busonero, D., Buzzi, R., Au, E. Ca Ff, Cambras, J., Campbell, H., Cancelliere, R., Cantat-Gaudin, T., Carlucci, T., Carrasco, J. M., Castellani, M., Charlot, P., Charnas, J., Charvet, P., Chassat, F., Chiavassa, A., Clotet, M., Cocozza, G., Collins, R. S., Collins, P., Costigan, G., Crifo, F., Cross, N. J. G., Crosta, M., Crowley, C., Dafonte, C., Damerdji, Y., Dapergolas, A., David, P., David, M., De Cat, P., de Felice, F., de Laverny, P., De Luise, F., De March, R., de Martino, D., de Souza, R., Debosscher, J., del Pozo, E., Delbo, M., Delgado, A., Delgado, H. E., di Marco, F., Di Matteo, P., Diakite, S., Distefano, E., Dolding, C., Dos Anjos, S., Drazinos, P., Duran, J., Dzigan, Y., Ecale, E., Edvardsson, Bengt, Enke, H., Erdmann, M., Escolar, D., Espina, M., Evans, N. W., Bontemps, G. Eynard, Fabre, C., Fabrizio, M., Faigler, S., Falcao, A. J., Farras Casas, M., Faye, F., Federici, L., Fedorets, G., Fernandez-Hernandez, J., Fernique, P., Fienga, A., Figueras, F., Filippi, F., Findeisen, K., Fonti, A., Fouesneau, M., Fraile, E., Fraser, M., Fuchs, J., Furnell, R., Gai, M., Galleti, S., Galluccio, L., Garabato, D., Garcia-Sedano, F., Gare, P., Garofalo, A., Garralda, N., Gavras, P., Gerssen, J., Geyer, R., Gilmore, G., Girona, S., Giuffrida, G., Gomes, M., Gonzalez-Marcos, A., Gonzalez-Nunez, J., Gonzalez-Vidal, J. J., Granvik, M., Guerrier, A., Guillout, P., Guiraud, J., Gurpide, A., Gutierrez-Sanchez, R., Guy, L. P., Haigron, R., Hatzidimitriou, D., Haywood, M., Heiter, Ulrike, Helmi, A., Hobbs, D., Hofmann, W., Holl, B., Holland, G., Hunt, J. A. S., Hypki, A., Icardi, V., Irwin, M., de Fombelle, G. Jevardat, Jofre, P., Jonker, P. G., Jorissen, A., Julbe, F., Karampelas, A., Kochoska, A., Kohley, R., Kolenberg, K., Kontizas, E., Koposov, S. E., Kordopatis, G., Koubsky, P., Kowalczyk, A., Krone-Martins, A., Kudryashova, M., Kull, I., Bachchan, R. K., Lacoste-Seris, F., Lanza, A. F., Lavigne, J. -B, Le Poncin-Lafitte, C., Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Lemaitre, V., Lenhardt, H., Leroux, F., Liao, S., Licata, E., Lindstrom, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Loeffler, W., Lopez, M., Lopez-Lozano, A., Lorenz, D., Loureiro, T., MacDonald, I., Magalhaes Fernandes, T., Managau, S., Mann, R. G., Mantelet, G., Marchal, O., Marchant, J. M., Marconi, M., Marie, J., Marinoni, S., Marrese, P. M., Marschalko, G., Marshall, D. J., Martin-Fleitas, J. M., Martino, M., Mary, N., Matijevic, G., Mazeh, T., McMillan, P. J., Messina, S., Mestre, A., Michalik, D., Millar, N. R., Miranda, B. M. H., Molina, D., Molinaro, R., Molinaro, M., Molnar, L., Moniez, M., Montegriffo, P., Monteiro, D., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morgenthaler, S., Morley, T., Morris, D., Mulone, A. F., Muraveva, T., Musella, I., Narbonne, J., Nelemans, G., Nicastro, L., Noval, L., Ordenovic, C., Ordieres-Mere, J., Osborne, P., Pagani, C., Pagano, I., Pailler, F., Palacin, H., Palaversa, L., Parsons, P., Paulsen, T., Pecoraro, M., Pedrosa, R., Pentikainen, H., Pereira, J., Pichon, B., Piersimoni, A. M., Pineau, F. -X, Plachy, E., Plum, G., Poujoulet, E., Prsa, A., Pulone, L., Ragaini, S., Rago, S., Rambaux, N., Ramos-Lerate, M., Ranalli, P., Rauw, G., Read, A., Regibo, S., Renk, F., Reyle, C., Ribeiro, R. A., Rimoldini, L., Ripepi, V., Riva, A., Rixon, G., Roelens, M., Romero-Gomez, M., Rowell, N., Royer, F., Rudolph, A., Ruiz-Dern, L., Sadowski, G., Selles, T. Sagrista, Sahlmann, J., Salgado, J., Salguero, E., Sarasso, M., Savietto, H., Schnorhk, A., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Segransan, D., Serpell, E., Shih, I-C, Smareglia, R., Smart, R. L., Smith, C., Solano, E., Solitro, F., Sordo, R., Nieto, S. Soria, Souchay, J., Spagna, A., Spoto, F., Stampa, U., Steele, I. A., Steidelmueller, H., Stephenson, C. A., Stoev, H., Suess, F. F., Suveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Tapiador, D., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Terrett, D., Tingley, B., Trager, S. C., Turon, C., Ulla, A., Utrilla, E., Valentini, G., van Elteren, A., Van Hemelryck, E., van Leeuwen, M., Varadi, M., Vecchiato, A., Veljanoski, J., Via, T., Vicente, D., Vogt, S., Voss, H., Votruba, V., Voutsinas, S., Walmsley, G., Weiler, M., Weingrill, K., Werner, D., Wevers, T., Whitehead, G., Wyrzykowski, L., Yoldas, A., Zerjal, M., Zucker, S., Zurbach, C., Zwitter, T., Alecu, A., Allen, M., Allende Prieto, C., Amorim, A., Anglada-Escude, G., Arsenijevic, V., Azaz, S., Balm, P., Beck, M., Bernstein, H. -H, Bigot, L., Bijaoui, A., Blasco, C., Bonfigli, M., Bono, G., Boudreault, S., Bressan, A., Brown, S., Brunet, P. -M, Bunclark, P., Buonanno, R., Butkevich, A. G., Carret, C., Carrion, C., Chemin, L., Chereau, F., Corcione, L., Darmigny, E., de Boer, K. S., de Teodoro, P., de Zeeuw, P. T., Delle Luche, C., Domingues, C. D., Dubath, P., Fodor, F., Frezouls, B., Fries, A., Fustes, D., Fyfe, D., Gallardo, E., Gallegos, J., Gardiol, D., Gebran, M., Gomboc, A., Gomez, A., Grux, E., Gueguen, A., Heyrovsky, A., Hoar, J., Iannicola, G., Parache, Y. Isasi, Janotto, A. -M, Joliet, E., Jonckheere, A., Keil, R., Kim, D. -W, Klagyivik, P., Klar, J., Knude, J., Kochukhov, Oleg, Kolka, I., Kos, J., Kutka, A., Lainey, V., LeBouquin, D., Liu, C., Loreggia, D., Makarov, V. V., Marseille, M. G., Martayan, C., Martinez-Rubi, O., Massart, B., Meynadier, F., Mignot, S., Munari, U., Nguyen, A. -T, Nordlander, Thomas, Ocvirk, P., O'Flaherty, K. S., Sanz, A. 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Abstract

Gaia is a cornerstone mission in the science programme of the European Space Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We pay special attention to the payload module, the performance of which is closely related to the scientific performance of the mission. We provide a summary of the commissioning activities and findings, followed by a description of the routine operational mode. We summarise scientific performance estimates on the basis of in-orbit operations. Several intermediate Gaia data releases are planned and the data can be retrieved from the Gaia Archive, which is available through the Gaia home page.

Published
2016
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