2019, Titarenko, A., Recio-Blanco, A., de Laverny, P., Hayden, M., Guiglion, G.

Chemical abundance dating methods open new paths for temporal evolution studies of the Milky Way stellar populations. In this paper, we use a high spectral resolution database of turn-off stars in the solar neighbourhood to study the age dependence of the [Y/Mg] chemical abundance ratio. Our analysis reveals a clear correlation between [Y/Mg] and age for thin disc stars of different metallicities, in synergy with previous studies of solar-type stars. In addition, no metallicity dependence with stellar age is detected, allowing us to use the [Y/Mg] ratio as a reliable age proxy. Finally, the [Y/Mg]-age relation presents a discontinuity between thin and thick disc stars around 9-10 Gyr. For thick disc stars, the correlation has a different zero point and probably a steeper trend with age, reflecting the different chemical evolution histories of the two disc components.

2018, Guiglion, G., de Laverny, P., Recio-Blanco, A., Prantzos, N.

Context. The chemical evolution of neutron capture elements in the Milky Way disc is still a matter of debate. There is a lack of statistically significant catalogues of such element abundances, especially those of the r-process. Aims. We aim to understand the chemical evolution of r-process elements in Milky Way disc. We focus on three pure r-process elements Eu, Gd, and Dy. We also consider a pure s-process element, Ba, in order to disentangle the different nucleosynthesis processes. Methods. We take advantage of high-resolution FEROS, HARPS, and UVES spectra from the ESO archive in order to perform a homogeneous analysis on 6500 FGK Milky Way stars. The chemical analysis is performed thanks to the automatic optimization pipeline GAUGUIN. We present abundances of Ba (5057 stars), Eu (6268 stars), Gd (5431 stars), and Dy (5479 stars). Based on the [α/Fe] ratio determined previously by the AMBRE Project, we chemically characterize the thin and the thick discs, and a metal-rich α-rich population. Results. First, we find that the [Eu/Fe] ratio follows a continuous sequence from the thin disc to the thick disc as a function of the metallicity. Second, in thick disc stars, the [Eu/Ba] ratio is found to be constant, while the [Gd/Ba] and [Dy/Ba] ratios decrease as a function of the metallicity. These observations clearly indicate a different nucleosynthesis history in the thick disc between Eu and Gd-Dy. The [r/Fe] ratio in the thin disc is roughly around +0.1 dex at solar metallicity, which is not the case for Ba. We also find that the α-rich metal-rich stars are also enriched in r-process elements (like thick disc stars), but their [Ba/Fe] is very different from thick disc stars. Finally, we find that the [r/α] ratio tends to decrease with metallicity, indicating that supernovae of different properties probably contribute differently to the synthesis of r-process elements and α-elements. Conclusions. We provide average abundance trends for [Ba/Fe] and [Eu/Fe] with rather small dispersions, and for the first time for [Gd/Fe] and [Dy/Fe]. This data may help to constrain chemical evolution models of Milky Way r- and s-process elements and the yields of massive stars. We emphasize that including yields of neutron-star or black hole mergers is now crucial if we want to quantitatively compare observations to Galactic chemical evolution models.

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.

2023, Magrini, L., Viscasillas Vázquez, C., Spina, L., Randich, S., Romano, D., Franciosini, E., Recio-Blanco, A., Nordlander, T., D'orazi, V., Baratella, M., Smiljanic, R., Dantas, M.L.L., Pasquini, L., Spitoni, E., Casali, G., Van Der Swaelmen, M., Bensby, T., Stonkute, E., Feltzing, S., Sacco, G.G., Bragaglia, A., Pancino, E., Heiter, U., Biazzo, K., Gilmore, G., Bergemann, M., Tautvaišienė, G., Worley, C., Hourihane, A., Gonneau, A., Morbidelli, L.

Context. The spatial distribution of elemental abundances and their time evolution are among the major constraints to disentangling the scenarios of formation and evolution of the Galaxy. Aims. In this paper we used the sample of open clusters available in the final release of the Gaia-ESO survey to trace the Galactic radial abundance and abundance-to-iron ratio gradients, and their time evolution. Methods. We selected member stars in 62 open clusters, with ages from 0.1 to about 7 Gyr, located in the Galactic thin disc at galactocentric radii (RGC) from about 6 to 21 kpc. We analysed the shape of the resulting [Fe/H] gradient, the average gradients [El/H] and [El/Fe] combining elements belonging to four different nucleosynthesis channels, and their individual abundance and abundance ratio gradients. We also investigated the time evolution of the gradients dividing open clusters in three age bins. Results. The [Fe/H] gradient has a slope of −0.054 dex kpc−1. It can be better approximated with a two-slope shape, steeper for RGC ≤ 11.2 kpc and flatter in the outer regions. We saw different behaviours for elements belonging to different channels. For the time evolution of the gradient, we found that the youngest clusters (age < 1 Gyr) in the inner disc have lower metallicity than their older counterparts and that they outline a flatter gradient. We considered some possible explanations, including the effects of gas inflow and migration. We suggest that the most likely one may be related to a bias introduced by the standard spectroscopic analysis producing lower metallicities in the analysis of low-gravity stars. Conclusions. To delineate the shape of the ‘true’ gradient, we should most likely limit our analysis to stars with low surface gravity log g >  2.5 and microturbulent parameter ξ <  1.8 km s−1. Based on this reduced sample, we can conclude that the gradient has minimally evolved over the time-frame outlined by the open clusters, indicating a slow and stationary formation of the thin disc over the last 3 Gyr. We found a secondary role of cluster migration in shaping the gradient, with a more prominent role of migration for the oldest clusters.