Search Results
Gaia Data Release 2 : Properties and validation of the radial velocities
2019, Katz, D., Sartoretti, P., Cropper, M., Panuzzo, P., Seabroke, G.M., Viala, Y., Benson, K., Blomme, R., Jasniewicz, G., Jean-Antoine, A., Huckle, H., Smith, M., Baker, S., Crifo, F., Damerdji, Y., David, M., Dolding, C., Frémat, Y., Gosset, E., Guerrier, A., Guy, L. P., Haigron, R., Janßen, K., Marchal, O., Plum, G., Soubiran, C., Thévenin, F., Ajaj, M., Allende Prieto, C., Babusiaux, C., Boudreault, S., Chemin, L., Delle Luche, C., Fabre, C., Gueguen, A., Hambly, N. C., Lasne, Y., Meynadier, F., Pailler, F., Panem, C., Royer, F., Tauran, G., Zurbach, C., Zwitter, T., Arenou, F., Bossini, D., Gerssen, J., Gómez, A., Lemaitre, V., Leclerc, N., Morel, T., Munari, U., Turon, C., Vallenari, A., Žerjal, M.
Context. For Gaia DR2, 280 million spectra collected by the Radial Velocity Spectrometer instrument on board Gaia were processed, and median radial velocities were derived for 9.8 million sources brighter than GRVS = 12 mag. Aims. This paper describes the validation and properties of the median radial velocities published in Gaia DR2. Methods. Quality tests and filters were applied to select those of the 9.8 million radial velocities that have the quality to be published in Gaia DR2. The accuracy of the selected sample was assessed with respect to ground-based catalogues. Its precision was estimated using both ground-based catalogues and the distribution of the Gaia radial velocity uncertainties. Results. Gaia DR2 contains median radial velocities for 7 224 631 stars, with Teff in the range [3550; 6900] K, which successfully passed the quality tests. The published median radial velocities provide a full-sky coverage and are complete with respect to the astrometric data to within 77.2% (for G ≤ 12:5 mag). The median radial velocity residuals with respect to the ground-based surveys vary from one catalogue to another, but do not exceed a few 100 m s-1. In addition, the Gaia radial velocities show a positive trend as a function of magnitude, which starts around GRVS ∼ 9 mag and reaches about +500 m s-1 at GRVS = 11:75 mag. The origin of the trend is under investigation, with the aim to correct for it in Gaia DR3. The overall precision, estimated from the median of the Gaia radial velocity uncertainties, is 1.05 km s-1. The radial velocity precision is a function of many parameters, in particular, the magnitude and effective temperature. For bright stars, GRVS 2 [4; 8] mag, the precision, estimated using the full dataset, is in the range 220-350 m s-1, which is about three to five times more precise than the pre-launch specification of 1 km s-1. At the faint end, GRVS = 11:75 mag, the precisions for Teff = 5000 and 6500 K are 1.4 and 3.7 km s-1, respectively.
Gaia Data Release 2 : Processing the spectroscopic data
2018, Sartoretti, P., Katz, D., Cropper, M., Panuzzo, P., Seabroke, G. M., Viala, Y., Benson, K., Blomme, R., Jasniewicz, G., Jean-Antoine, A., Huckle, H., Smith, M., Baker, S., Crifo, F., Damerdji, Y., David, M., Dolding, C., Frémat, Y., Gosset, E., Guerrier, A., Guy, L. P., Haigron, R., Janßen, K., Marchal, O., Plum, G., Soubiran, C., Thévenin, F., Ajaj, M., Allende Prieto, C., Babusiaux, C., Boudreault, S., Chemin, L., Delle Luche, C., Fabre, C., Gueguen, A., Hambly, N. C., Lasne, Y., Meynadier, F., Pailler, F., Panem, C., Riclet, F., Royer, F., Tauran, G., Zurbach, C., Zwitter, T., Arenou, F., Gomez, A., Lemaitre, V., Leclerc, N., Morel, T., Munari, U., Turon, C., Žerjal, M.
Context. The Gaia Data Release 2 (DR2 ) contains the first release of radial velocities complementing the kinematic data of a sample of about 7 million relatively bright, late-type stars. Aims. This paper provides a detailed description of the Gaia spectroscopic data processing pipeline, and of the approach adopted to derive the radial velocities presented in DR2 . Methods. The pipeline must perform four main tasks: (i) clean and reduce the spectra observed with the Radial Velocity Spectrometer (RVS); (ii) calibrate the RVS instrument, including wavelength, straylight, line-spread function, bias non-uniformity, and photometric zeropoint; (iii) extract the radial velocities; and (iv) verify the accuracy and precision of the results. The radial velocity of a star is obtained through a fit of the RVS spectrum relative to an appropriate synthetic template spectrum. An additional task of the spectroscopic pipeline was to provide first-order estimates of the stellar atmospheric parameters required to select such template spectra. We describe the pipeline features and present the detailed calibration algorithms and software solutions we used to produce the radial velocities published in DR2 . Results. The spectroscopic processing pipeline produced median radial velocities for Gaia stars with narrow-band near-IR magnitude GRVS ≤ 12 (i.e. brighter than V ∼ 13). Stars identified as double-lined spectroscopic binaries were removed from the pipeline, while variable stars, single-lined, and non-detected double-lined spectroscopic binaries were treated as single stars. The scatter in radial velocity among different observations of a same star, also published in Gaia DR2, provides information about radial velocity variability. For the hottest (Te≥ 7000 K) and coolest (Te≤ 3500 K) stars, the accuracy and precision of the stellar parameter estimates are not sufficient to allow selection of appropriate templates. The radial velocities obtained for these stars were removed from DR2 . The pipeline also provides a first-order estimate of the performance obtained. The overall accuracy of radial velocity measurements is around ∼200-300 m s-1, and the overall precision is ∼1 km s-1; it reaches ∼200 m s-1 for the brightest stars.
Abundance-age relations with red clump stars in open clusters
2021, Casamiquela, L., Soubiran, C., Jofré, P., Chiappini, C., Lagarde, N., Tarricq, Y., Carrera, R., Jordi, C., Balaguer-Núñez, L., Carbajo-Hijarrubia, J., Blanco-Cuaresma, S.
Context. Precise chemical abundances coupled with reliable ages are key ingredients to understanding the chemical history of our Galaxy. Open clusters (OCs) are useful for this purpose because they provide ages with good precision. Aims. The aim of this work is to investigate the relation between different chemical abundance ratios and age traced by red clump (RC) stars in OCs. Methods. We analyzed a large sample of 209 reliable members in 47 OCs with available high-resolution spectroscopy. We applied a differential line-by-line analysis, performing a comprehensive chemical study of 25 chemical species. This sample is among the largest samples of OCs homogeneously characterized in terms of atmospheric parameters, detailed chemistry, and age. Results. In our metallicity range (-0.2 < [M/H] < +0.2) we find that while most Fe-peak and α elements show a flat dependence on age, the s-process elements show a decreasing trend with increasing age with a remarkable knee at 1 Gyr. For Ba, Ce, Y, Mo, and Zr, we find a plateau at young ages (< 1 Gyr). We investigate the relations between all possible combinations among the computed chemical species and age. We find 19 combinations with significant slopes, including [Y/Mg] and [Y/Al]. The ratio [Ba/α] shows the most significant correlation. Conclusions. We find that the [Y/Mg] relation found in the literature using solar twins is compatible with the one found here in the solar neighborhood. The age-abundance relations in clusters at large distances(d > 1 kpc) show larger scatter than those in clusters in the solar neighborhood, particularly in the outer disk. We conclude that, in addition to pure nucleosynthetic arguments, the complexity of the chemical space introduced by the Galactic dynamics must be taken into account in order to understand these relations, especially outside of the local bubble. © L. Casamiquela et al. 2021.
Gaia Data Release 2 : The catalogue of radial velocity standard stars
2018, Soubiran, C., Jasniewicz, G., Chemin, L., Zurbach, C., Brouillet, N., Panuzzo, P., Sartoretti, P., Katz, D., Le Campion, J.-F., Marchal, O., Hestroffer, D., Thévenin, F., Crifo, F., Udry, S., Cropper, M., Seabroke, G., Viala, Y., Benson, K., Blomme, R., Jean-Antoine, A., Huckle, H., Smith, M., Baker, S. G., Damerdji, Y., Dolding, C., Frémat, Y., Gosset, E., Guerrier, A., Guy, L. P., Haigron, R., Janßen, K., Plum, G., Fabre, C., Lasne, Y., Pailler, F., Panem, C., Riclet, F., Royer, F., Tauran, G., Zwitter, T., Gueguen, A., Turon, C.
Aims. The Radial Velocity Spectrometer (RVS) on board the ESA satellite mission Gaia has no calibration device. Therefore, the radial velocity zero point needs to be calibrated with stars that are proved to be stable at a level of 300 m s-1 during the Gaia observations. Methods. We compiled a dataset of ~71 000 radial velocity measurements from five high-resolution spectrographs. A catalogue of 4813 stars was built by combining these individual measurements. The zero point was established using asteroids. Results. The resulting catalogue has seven observations per star on average on a typical time baseline of 6 yr, with a median standard deviation of 15 m s-1. A subset of the most stable stars fulfilling the RVS requirements was used to establish the radial velocity zero point provided in Gaia Data Release 2. The stars that were not used for calibration are used to validate the RVS data.
Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)
2022, Klioner, S.A., Lindegren, L., Mignard, F., Hernández, J., Ramos-Lerate, M., Bastian, U., Biermann, M., Bombrun, A., De Torres, A., Gerlach, E., Geyer, R., Fraile, E., Garabato, D., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J.-L., Hambly, N.C., Harrison, D.L., Hestroffer, D., Hodgkin, S.T., Hilger, T., Holl, B., Janben, K., Jevardat De Fombelle, G., Jordan, S., Krone-Martins, A., Lanzafame, A.C., Löffler, W., Marchal, O., Marrese, P.M., Moitinho, A., Hobbs, D., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Reylé, C., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Lammers, U.L., Sarro, L.M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., Van Leeuwen, M., Abbas, U., Ábrahám, P., Abreu Aramburu, A., Aerts, C., McMillan, P.J., Aguado, J.J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M.A., Alves, J., Anderson, R.I., Anglada Varela, E., Antoja, T., Baines, D., Steidelmüller, H., Baker, S.G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M.A., Bassilana, J.-L., Bauchet, N., Teyssier, D., Becciani, U., Bellazzini, M., Berihuete, A., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Boch, T., Bossini, D., Bouquillon, S., Raiteri, C.M., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A.G., Buzzi, R., Bartolomé, S., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M.I., Carrasco, J.M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Bernet, M., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W.J., Cornez, T., Castañeda, J., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., De Laverny, P., De Luise, F., Clotet, M., De March, R., De Ridder, J., De Souza, R., Del Peloso, E.F., Del Pozo, E., Delbo, M., Delgado, A., Delisle, J.-B., Demouchy, C., Dharmawardena, T.E., Davidson, M., Diakite, S., Diener, C., Distefano, E., Dolding, C., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fabricius, C., Fienga, A., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Garralda Torres, N., Gavel, A., Gavras, P., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., González-Núñez, J., González-Santamaría, I., González-Vidal, J.J., Granvik, M., Guillout, P., Guiraud, J., Gutiérrez-Sánchez, R., Guy, L.P., Hatzidimitriou, D., Hauser, M., Haywood, M., Helmer, A., Helmi, A., Portell, J., Sarmiento, M.H., Hidalgo, S.L., Hładczuk, N., Holland, G., Huckle, H.E., Jardine, K., Jasniewicz, G., Jean-Antoine Piccolo, A., Jiménez-Arranz, O., Juaristi Campillo, J., Rowell, N., Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kordopatis, G., Korn, A.J., Kóspál, A., Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Torra, F., Laizeau, P., Lambert, S., Lanza, A.F., Lasne, Y., Le Campion, J.-F., Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Torra, J., Liao, S., Licata, E.L., Lindstrøm, H.E.P., Lister, T.A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Madrero Pardo, P., Magdaleno Romeo, A., Brown, A.G.A., Managau, S., Mann, R.G., Manteiga, M., Marchant, J.M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Marín Pina, D., Marinoni, S., Marocco, F., Vallenari, A., Marshall, D.J., Polo, L. Martin, Martín-Fleitas, J.M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., Messina, S., Prusti, T., Michalik, D., Millar, N.R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., De Bruijne, J.H.J., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C.P., Musella, I., Nagy, Z., Noval, L., Arenou, F., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J.O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P.A., Pallas-Quintela, L., Panahi, A., Babusiaux, C., Payne-Wardenaar, S., Peñalosa Esteller, X., Penttilä, A., Pichon, B., Piersimoni, A.M., Pineau, F.-X., Plachy, E., Plum, G., Poggio, E., Prša, A., Creevey, O.L., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Rambaux, N., Ramos, P., Re Fiorentin, P., Regibo, S., Richards, P.J., Diaz, C. Rios, Ducourant, C., Ripepi, V., Riva, A., Rix, H.-W., Rixon, G., Robichon, N., Robin, A.C., Robin, C., Roelens, M., Rogues, H.R.O., Rohrbasser, L., Evans, D.W., Romero-Gómez, M., Royer, F., Ruz Mieres, D., Rybicki, K.A., Sadowski, G., Sáez Núñez, A., Sagristà Sellés, A., Sahlmann, J., Salguero, E., Samaras, N., Eyer, L., Sanchez Gimenez, V., Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J.C., Ségransan, D., Semeux, D., Guerra, R., Shahaf, S., Siddiqui, H.I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R.L., Snaith, O.N., Solano, E., Hutton, A., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I.A., Stephenson, C.A., Süveges, M., Surdej, J., Jordi, C., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M.B., Teixeira, R., Tolomei, L., Tonello, N., Torralba Elipe, G., Trabucchi, M., Tsounis, A.T., Luri, X., Turon, C., Ulla, A., Unger, N., Vaillant, M.V., Van Dillen, E., Van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Panem, C., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, L., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., Zwitter, T., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N.A., Bailer-Jones, C.A.L., Drimmel, R., Jansen, F., Katz, D., Lattanzi, M.G., Van Leeuwen, F., Bakker, J., Cacciari, C., De Angeli, F., Fouesneau, M., Frémat, Y., Galluccio, L., Guerrier, A., Heiter, U., Masana, E., Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Seabroke, G.M., Sordo, R., Thévenin, F., Gracia-Abril, G., Altmann, M., Andrae, R., Audard, M., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Burgess, P.W., Busonero, D., Busso, G., Cánovas, H., Carry, B., Cellino, A., Cheek, N., Clementini, G., Damerdji, Y., De Teodoro, P., Nuñez Campos, M., Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J.
Context. Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. Aims. We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International Celestial Reference Frame (ICRF3). Results. Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutions in Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13-21 with a peak density at 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of 12 μas yr-1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands, the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline the future of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extract information about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of an astrometric solution.