Author: "Haywood, M" - Searchworks@Jio Institute Digital Library Search Results

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508 results on '"Haywood, M"'

1. Discovery of a dormant 33 solar-mass black hole in pre-release Gaia astrometry

Author: Gaia Collaboration, Panuzzo, P., Mazeh, T., Arenou, F., Holl, B., Caffau, E., Jorissen, A., Babusiaux, C., Gavras, P., Sahlmann, J., Bastian, U., Wyrzykowski, Ł., Eyer, L., Leclerc, N., Bauchet, N., Bombrun, A., Mowlavi, N., Seabroke, G. M., Teyssier, D., Balbinot, E., Helmi, A., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Barbier, A., Biermann, M., Creevey, O. L., Ducourant, C., Evans, D. W., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Mignard, F., Nicolas, C., Randich, S., Sartoretti, P., Smiljanic, R., Tanga, P., Walton, N. A., Aerts, C., Bailer-Jones, C. A. L., Cropper, M., Drimmel, R., Jansen, F., Katz, D., Lattanzi, M. G., Soubiran, C., Thévenin, F., van Leeuwen, F., Andrae, R., Audard, M., Bakker, J., Blomme, R., Castañeda, J., De Angeli, F., Fabricius, C., Fouesneau, M., Frémat, Y., Galluccio, L., Guerrier, A., Heiter, U., Masana, E., Messineo, R., Nienartowicz, K., Pailler, F., Riclet, F., Roux, W., Sordo, R., Gracia-Abril, G., Portell, J., Altmann, M., Benson, K., Berthier, J., Burgess, P. W., Busonero, D., Busso, G., Cacciari, C., Cánovas, H., Carrasco, J. M., Carry, B., Cellino, A., Cheek, N., Clementini, G., Damerdji, Y., Davidson, M., de Teodoro, P., Delchambre, L., Dell'Oro, A., Garcia, E. Fraile, Garabato, D., García-Lario, P., Haigron, R., Hambly, N. C., Harrison, D. L., Hatzidimitriou, D., Hernández, J., Hestroffer, D., Hodgkin, S. T., Jamal, S., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Lorca, A., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Campos, M. Nuñez, Oreshina-Slezak, I., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Riello, M., Rimoldini, L., Robin, A. C., Roegiers, T., Sarro, L. M., Schultheis, M., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Weingrill, K., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Ahmed, S., Altavilla, G., Álvarez, M. A., Anders, F., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baig, S., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balog, Z., Barache, C., Barros, M., Barstow, M. A., Bartolomé, S., Bashi, D., Bassilana, J. -L., Baudeau, N., Becciani, U., Bedin, L. R., Bellas-Velidis, I., Bellazzini, M., Beordo, W., Bernet, M., Bertolotto, C., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Bland-Hawthorn, J., Blazere, A., Boch, T., Bossini, D., Bouquillon, S., Bragaglia, A., Braine, J., Bratsolis, E., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Butkevich, A. G., Buzzi, R., Camut, A., Cancelliere, R., Cantat-Gaudin, T., Guilarte, D. Capilla, Carballo, R., Carlucci, T., Carnerero, M. I., Carretero, J., Carton, S., Casamiquela, L., Casey, A., Castellani, M., Castro-Ginard, A., Ceraj, L., Cesare, V., Charlot, P., Chaudet, C., Chemin, L., Chiavassa, A., Chornay, N., Chosson, D., Cooper, W. J., Cornez, T., Cowell, S., Crosta, M., Crowley, C., Reyes, M. Cruz, Dafonte, C., Ponte, M. Dal, David, M., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Torres, A., del Peloso, E. F., Delbo, M., Delgado, A., Delisle, J. -B., Demouchy, C., Denis, E., Dharmawardena, T. E., Di Giacomo, F., Diener, C., Distefano, E., Dolding, C., Dsilva, K., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fatović, M., Fedorets, G., Fernández-Hernández, J., Fernique, P., Figueras, F., Fouron, C., Fragkoudi, F., Gai, M., Galinier, M., Garcia-Serrano, A., García-Torres, M., Garofalo, A., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomboc, A., Gomez, A., González-Santamaría, I., Gosset, E., Granvik, M., Barrera, V. Gregori, Gutiérrez-Sánchez, R., Haywood, M., Helmer, A., Hidalgo, S. L., Hilger, T., Hobbs, D., Hottier, C., Huckle, H. E., Jiménez-Arranz, Ó., Campillo, J. Juaristi, Kaczmarek, Z., Kervella, P., Khanna, S., Kontizas, M., Kordopatis, G., Korn, A. J., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Lambert, S., Lanza, A. F., Lebreton, Y., Lebzelter, T., Leccia, S., Lecoutre, G., Liao, S., Liberato, L., Licata, E., Livanou, E., Lobel, A., López-Miralles, J., Loup, C., Madarász, M., Mahy, L., Mann, R. G., Manteiga, M., Marinoni, S., Marcellino, C. P., Marshall, D. J., Mascarenhas, D., Marchant, J. M., Lozano, J. Martín, Masip, A., Marconi, M., Pina, D. Marín, Polo, L. Martin, Martín-Fleitas, J. M., Mastrobuono-Battisti, A., McMillan, P. J., Meichsner, J. G. Marton, Merc, J., Messina, S., Millar, N. R., Mints, A., Mohamed, D., Molina, D., Molinaro, R., Monguió, M., Montegriffo, P., Monti, L., Mora, A., Morbidelli, R., Morris, D., Mudimadugula, R., Muraveva, T., Musella, I., Nagy, Z., Nardetto, N., Navarrete, C., Oh, S., Ordenovic, C., Orenstein, O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Pawlak, M., Penttilä, A., Pesciullesi, P., Pinamonti, M., Plachy, E., Planquart, L., Plum, G., Poggio, E., Pourbaix, D., Price-Whelan, A. M., Pulone, L., Rabin, V., Rainer, M., Raiteri, C. M., Ramos, P., Ramos-Lerate, M., Ratajczak, M., Fiorentin, P. Re, Regibo, S., Reylé, C., Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robert, G., Robichon, N., Robin, C., Romero-Gómez, M., Rowell, N., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Sellés, A. Sagristà, Sanna, N., Santoveña, R., Sarasso, M., Sarmiento, M. H., Riera, C. Sarrate, Sciacca, E., Ségransan, D., Semczuk, M., Shahaf, S., Siebert, A., Slezak18, E., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spitoni, E., Spoto, F., Squillante, L. A., Steele, I. A., Steidelmüller, H., Surdej, J., Szabados, L., Taris, F., Taylor, M. B., Teixeira, R., Tepper-Garcia, T., Thuillot, W., Tolomei, L., Tonello, N., Torra, F., Elipe, G. Torralba, Trabucchi, M., Trentin, E., Tsantaki, M., Turon, C., Ulla, A., Unger, N., Valtchanov, I., Vanel, O., Vecchiato, A., Vicente, D., Villar, E., Weiler, M., Zhao, H., Zorec, J., Zucker, S., Župić, A., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: Gravitational waves from black-hole merging events have revealed a population of extra-galactic BHs residing in short-period binaries with masses that are higher than expected based on most stellar evolution models - and also higher than known stellar-origin black holes in our Galaxy. It has been proposed that those high-mass BHs are the remnants of massive metal-poor stars. Gaia astrometry is expected to uncover many Galactic wide-binary systems containing dormant BHs, which may not have been detected before. The study of this population will provide new information on the BH-mass distribution in binaries and shed light on their formation mechanisms and progenitors. As part of the validation efforts in preparation for the fourth Gaia data release (DR4), we analysed the preliminary astrometric binary solutions, obtained by the Gaia Non-Single Star pipeline, to verify their significance and to minimise false-detection rates in high-mass-function orbital solutions. The astrometric binary solution of one source, Gaia BH3, implies the presence of a 32.70 \pm 0.82 M\odot BH in a binary system with a period of 11.6 yr. Gaia radial velocities independently validate the astrometric orbit. Broad-band photometric and spectroscopic data show that the visible component is an old, very metal-poor giant of the Galactic halo, at a distance of 590 pc. The BH in the Gaia BH3 system is more massive than any other Galactic stellar-origin BH known thus far. The low metallicity of the star companion supports the scenario that metal-poor massive stars are progenitors of the high-mass BHs detected by gravitational-wave telescopes. The Galactic orbit of the system and its metallicity indicate that it might belong to the Sequoia halo substructure. Alternatively, and more plausibly, it could belong to the ED-2 stream, which likely originated from a globular cluster that had been disrupted by the Milky Way., Comment: 23 pages, accepted fro publication in A&A Letters. New version with small fixes
Published: 2024
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2. The Gaia RVS benchmark stars II. A sample of stars selected for their Gaia high radial velocity

Author: Caffau, E., Katz, D., Gómez, A., Bonifacio, P., Lallement, R., Sartoretti, P., Sbordone, L., Spite, M., Mucciarelli, A., Ibata, R., Chemin, L., Thévenin, F., Panuzzo, P., Leclerc, N., François, P., Ludwig, H. -G., Monaco, L., Haywood, M., and Soubiran, C.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The Gaia satellite has already provided the astronomical community with three data releases, and the Radial Velocity Spectrometer (RVS) on board Gaia has provided the radial velocity for 33 million stars. When deriving the radial velocity from the RVS spectra, several stars are measured to have large values. To verify the credibility of these measurements, we selected some bright stars with the modulus of radial velocity in excess of 500\ to be observed with SOPHIE at OHP and UVES at VLT. This paper is devoted to investigating the chemical composition of the stars observed with UVES. We derived atmospheric parameters using Gaia photometry and parallaxes, and we performed a chemical analysis using the code. We find that the sample consists of metal-poor stars, although none have extremely low metallicities. The abundance patterns match what has been found in other samples of metal-poor stars selected irrespective of their radial velocities. We highlight the presence of three stars with low Cu and Zn abundances that are likely descendants of pair-instability supernovae. Two stars are apparently younger than 1\,Ga, and their masses exceed twice the turn-off mass of metal-poor populations. This makes it unlikely that they are blue stragglers because it would imply they formed from triple or multiple systems. We suggest instead that they are young metal-poor stars accreted from a dwarf galaxy. Finally, we find that the star RVS721 is associated with the Gjoll stream, which itself is associated with the Globular Cluster NGC\,3201., Comment: Astronomy and Astrophysics - A\&A, In press
Published: 2024
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3. Metallicity distributions of halo stars: do they trace the Galactic accretion history?

Author: Mori, A., Di Matteo, P., Salvadori, S., Khoperskov, S., Pagnini, G., and Haywood, M.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The standard cosmological scenario predicts a hierarchical formation for galaxies. Many substructures were found in the Galactic halo, identified as clumps in kinematic spaces, like the energy-angular momentum one (E-Lz), under the hypothesis of the conservation of these quantities. If these clumps also feature different chemical properties, e.g. metallicity distribution functions (MDF), they are often associated to independent merger debris. The aim of this study is to explore to what extent we can couple kinematics and metallicities of stars in the Galactic halo to reconstruct the accretion history of the Milky Way. In particular, we want to understand whether different clumps in the E-Lz space with different MDF should be associated to distinct merger debris. We analysed dissipationless, self-consistent high-resolution N-body simulations of a MW-type galaxy accreting a satellite with mass ratio 1:10, with different orbital parameters and metallicity gradients (assigned a posteriori). We confirm that accreted stars from a ~1:10 satellite redistribute in a wide range of E and Lz, due to the dynamical friction, thus not being associated to a single clump. Because satellite stars with different metallicities can be deposited in different regions of the E-Lz space (on average the more metal-rich ones end up more gravitationally bound to the MW), this implies that a single ~1:10 accretion can manifest with different MDFs, in different regions of the E-Lz space. Groups of stars with different E, Lz and metallicities may be interpreted as originating from different satellites, but our analysis shows that these interpretations are not physically motivated. In fact, the coupling of kinematics with MDFs to reconstruct the accretion history of the MW can bias the reconstructed merger tree towards increasing the number of past accretions and decreasing the masses of the progenitor galaxies., Comment: Submitted to A&A. Comments are welcome
Published: 2024

4. Gaia Focused Product Release: Sources from Service Interface Function image analysis -- Half a million new sources in omega Centauri

Author: Gaia Collaboration, Weingrill, K., Mints, A., Castañeda, J., Kostrzewa-Rutkowska, Z., Davidson, M., De Angeli, F., Hernández, J., Torra, F., Ramos-Lerate, M., Babusiaux, C., Biermann, M., Crowley, C., Evans, D. W., Lindegren, L., Martín-Fleitas, J. M., Palaversa, L., Mieres, D. Ruz, Tisanić, K., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Barbier, A., Creevey, O. L., Ducourant, C., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U., Luri, X., Mignard, F., Randich, S., Sartoretti, P., Smiljanic, R., Tanga, P., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Cropper, M., Drimmel, R., Katz, D., Soubiran, C., van Leeuwen, F., Audard, M., Bakker, J., Blomme, R., Fabricius, C., Fouesneau, M., Frémat, Y., Galluccio, L., Guerrier, A., Masana, E., Messineo, R., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Seabroke, G. M., Sordo, R., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Benson, K., Berthier, J., Burgess, P. W., Busonero, D., Busso, G., Cánovas, H., Carry, B., Cheek, N., Clementini, G., Damerdji, Y., de Teodoro, P., Delchambre, L., DellÓro, A., Garcia, E. Fraile, Garabato, D., García-Lario, P., Torres, N. Garralda, Gavras, P., Haigron, R., Hambly, N. C., Harrison, D. L., Hatzidimitriou, D., Hodgkin, S. T., Holl, B., Jamal, S., Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Lorca, A., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Campos, M. Nuñez, Oreshina-Slezak, I., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Riello, M., Rimoldini, L., Robin, A. C., Roegiers, T., Sarro, L. M., Schultheis, M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Altavilla, G., Álvarez, M. A., Alves, J., Anders, F., Anderson, R. I., Antoja, T., Baines, D., Baker, S. G., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bashi, D., Bauchet, N., Baudeau, N., Becciani, U., Bedin, L. R., Bellas-Velidis, I., Bellazzini, M., Beordo, W., Berihuete, A., Bernet, M., Bertolotto, C., Bertone, S., Bianchi, L., Binnenfeld, A., Blazere, A., Boch, T., Bombrun, A., Bouquillon, S., Bragaglia, A., Braine, J., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cannizzo, S., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Carretero, J., Carton, S., Casamiquela, L., Castellani, M., Castro-Ginard, A., Cesare, V., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Collins, R., Contursi, G., Cooper, W. J., Cornez, T., Crosta, M., Dafonte, C., de Laverny, P., De Luise, F., De March, R., de Souza, R., de Torres, A., del Peloso, E. F., Delbo, M., Delgado, A., Dharmawardena, T. E., Diakite, S., Diener, C., Distefano, E., Dolding, C., Dsilva, K., Durán, J., Enke, H., Esquej, P., Fabre, C., Fabrizio, M., Faigler, S., Fatović, M., Fedorets, G., Fernández-Hernández, J., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Gai, M., Galinier, M., Garcia-Gutierrez, A., García-Torres, M., Garofalo, A., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., González-Núñez, J., González-Santamaría, I., Gosset, E., Granvik, M., Barrera, V. Gregori, Gutiérrez-Sánchez, R., Haywood, M., Helmer, A., Helmi, A., Henares, K., Hidalgo, S. L., Hilger, T., Hobbs, D., Hottier, C., Huckle, H. E., Jabłońska, M., Jansen, F., Jiménez-Arranz, Ó., Campillo, J. Juaristi, Khanna, S., Kordopatis, G., Kóspál, Á, Kun, M., Lambert, S., Lanza, A. F., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Lecoeur-Taibi, I., Lecoutre, G., Liao, S., Liberato, L., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Loup, C., Mahy, L., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Pina, D. Marín, Marinoni, S., Marshall, D. J., Lozano, J. Martín, Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Meichsner, J., Messina, S., Michalik, D., Millar, N. R., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Mowlavi, N., Munoz, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Nieto, S., Noval, L., Ogden, A., Ordenovic, C., Pagani, C., Pagano, I., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Panem, C., Payne-Wardenaar, S., Pegoraro, L., Penttilä, A., Pesciullesi, P., Piersimoni, A. M., Pinamonti, M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Pourbaix, D., Prša, A., Pulone, L., Racero, E., Rainer, M., Raiteri, C. M., Ramos, P., Ratajczak, M., Fiorentin, P. Re, Regibo, S., Reylé, C., Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, C., Romero-Gómez, M., Rowell, N., Royer, F., Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Riera, C. Sarrate, Sciacca, E., Segovia, J. C., Ségransan, D., Shahaf, S., Siebert, A., Siltala, L., Slezak, E., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spina, L., Spitoni, E., Spoto, F., Squillante, L. A., Steele, I. A., Steidelmüller, H., Surdej, J., Szabados, L., Taris, F., Taylor, M. B., Teixeira, R., Tolomei, L., Elipe, G. Torralba, Trabucchi, M., Tsantaki, M., Ulla, A., Unger, N., Vanel, O., Vecchiato, A., Vicente, D., Voutsinas, S., Weiler, M., Wyrzykowski, Ł., Zhao, H., Zorec, J., Zwitter, T., Balaguer-Núñez, L., Leclerc, N., Morgenthaler, S., Robert, G., and Zucker, S.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: Gaia's readout window strategy is challenged by very dense fields in the sky. Therefore, in addition to standard Gaia observations, full Sky Mapper (SM) images were recorded for nine selected regions in the sky. A new software pipeline exploits these Service Interface Function (SIF) images of crowded fields (CFs), making use of the availability of the full two-dimensional (2D) information. This new pipeline produced half a million additional Gaia sources in the region of the omega Centauri ($\omega$ Cen) cluster, which are published with this Focused Product Release. We discuss the dedicated SIF CF data reduction pipeline, validate its data products, and introduce their Gaia archive table. Our aim is to improve the completeness of the {\it Gaia} source inventory in a very dense region in the sky, $\omega$ Cen. An adapted version of {\it Gaia}'s Source Detection and Image Parameter Determination software located sources in the 2D SIF CF images. We validated the results by comparing them to the public {\it Gaia} DR3 catalogue and external Hubble Space Telescope data. With this Focused Product Release, 526\,587 new sources have been added to the {\it Gaia} catalogue in $\omega$ Cen. Apart from positions and brightnesses, the additional catalogue contains parallaxes and proper motions, but no meaningful colour information. While SIF CF source parameters generally have a lower precision than nominal {\it Gaia} sources, in the cluster centre they increase the depth of the combined catalogue by three magnitudes and improve the source density by a factor of ten. This first SIF CF data publication already adds great value to the {\it Gaia} catalogue. It demonstrates what to expect for the fourth {\it Gaia} catalogue, which will contain additional sources for all nine SIF CF regions.
Published: 2023
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5. Gaia Focused Product Release: A catalogue of sources around quasars to search for strongly lensed quasars

Author: Gaia Collaboration, Krone-Martins, A., Ducourant, C., Galluccio, L., Delchambre, L., Oreshina-Slezak, I., Teixeira, R., Braine, J., Campion, J. -F. Le, Mignard, F., Roux, W., Blazere, A., Pegoraro, L., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Barbier, A., Biermann, M., Creevey, O. L., Evans, D. W., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Randich, S., Sartoretti, P., Smiljanic, R., Tanga, P., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Cropper, M., Drimmel, R., Katz, D., Soubiran, C., van Leeuwen, F., Audard, M., Bakker, J., Blomme, R., Castaneda, J., De Angeli, F., Fabricius, C., Fouesneau, M., Fremat, Y., Guerrier, A., Masana, E., Messineo, R., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Seabroke, G. M., Sordo, R., Thevenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Benson, K., Berthier, J., Burgess, P. W., Busonero, D., Busso, G., Canovas, H., Carry, B., Cheek, N., Clementini, G., Damerdji, Y., Davidson, M., de Teodoro, P., Dell'Oro, A., Garcia, E. Fraile, Garabato, D., Garcia-Lario, P., Torres, N. Garralda, Gavras, P., Haigron, R., Hambly, N. C., Harrison, D. L., Hatzidimitriou, D., Hernandez, J., Hodgkin, S. T., Holl, B., Jamal, S., Jordan, S., Lanzafame, A. C., Loffler, W., Lorca, A., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Campos, M. Nunez, Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Riello, M., Rimoldini, L., Robin, A. C., Roegiers, T., Sarro, L. M., Schultheis, M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Weingrill, K., Abbas, U., Abraham, P., Aramburu, A. Abreu, Aerts, C., Altavilla, G., Alvarez, M. A., Alves, J., Anderson, R. I., Antoja, T., Baines, D., Baker, S. G., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolome, S., Bashi, D., Bauchet, N., Baudeau, N., Becciani, U., Bedin, L. R., Bellas-Velidis, I., Bellazzini, M., Beordo, W., Berihuete, A., Bernet, M., Bertolotto, C., Bertone, S., Bianchi, L., Binnenfeld, A., Boch, T., Bombrun, A., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cannizzo, S., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Carretero, J., Carton, S., Casamiquela, L., Castellani, M., Castro-Ginard, A., Cesare, V., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Collins, R., Contursi, G., Cooper, W. J., Cornez, T., Crosta, M., Crowley, C., Dafonte, C., de Laverny, P., De Luise, F., De March, R., de Souza, R., de Torres, A., del Peloso, E. F., Delbo, M., Delgado, A., Dharmawardena, T. E., Diakite, S., Diener, C., Distefano, E., Dolding, C., Dsilva, K., Duran, J., Enke, H., Esquej, P., Fabre, C., Fabrizio, M., Faigler, S., Fatovic, M., Fedorets, G., Fernandez-Hernandez, J., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Gai, M., Galinier, M., Garcia-Gutierrez, A., Garcia-Torres, M., Garofalo, A., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., Gonzalez-Nunez, J., Gonzalez-Santamaria, I., Gosset, E., Granvik, M., Barrera, V. Gregori, Gutierrez-Sanchez, R., Haywood, M., Helmer, A., Helmi, A., Henares, K., Hidalgo, S. L., Hilger, T., Hobbs, D., Hottier, C., Huckle, H. E., Jablonska, M., Jansen, F., Jimenez-Arranz, O., Campillo, J. Juaristi, Khanna, S., Kordopatis, G., Kospal, A., Kostrzewa-Rutkowska, Z., Kun, M., Lambert, S., Lanza, A. F., Lebreton, Y., Lebzelter, T., Leccia, S., Lecoeur-Taibi, I., Lecoutre, G., Liao, S., Liberato, L., Licata, E., Lindstrom, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Loup, C., Mahy, L., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Pina, D. Marin, Marinoni, S., Marshall, D. J., Lozano, J. Martin, Martin-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Meichsner, J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnar, L., Monari, G., Monguio, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Mowlavi, N., Munoz, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Nieto, S., Noval, L., Ogden, A., Ordenovic, C., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Panem, C., Payne-Wardenaar, S., Penttila, A., Pesciullesi, P., Piersimoni, A. M., Pinamonti, M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Pourbaix, D., Prsa, A., Pulone, L., Racero, E., Rainer, M., Raiteri, C. M., Ramos, P., Ramos-Lerate, M., Ratajczak, M., Fiorentin, P. Re, Regibo, S., Reyle, C., Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, C., Romero-Gomez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Nunez, A. Saez, Selles, A. Sagrista, Sahlmann, J., Gimenez, V. Sanchez, Sanna, N., Santovena, R., Sarasso, M., Riera, C. Sarrate, Sciacca, E., Segovia, J. C., Segransan, D., Shahaf, S., Siebert, A., Siltala, L., Slezak, E., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spina, L., Spitoni, E., Spoto, F., Squillante, L. A., Steele, I. A., Steidelmuller, H., Surdej, J., Szabados, L., Taris, F., Taylor, M. B., Tisanic, K., Tolomei, L., Torra, F., Elipe, G. Torralba, Trabucchi, M., Tsantaki, M., Ulla, A., Unger, N., Vanel, O., Vecchiato, A., Vicente, D., Voutsinas, S., Weiler, M., Wyrzykowski, L., Zhao, H., Zorec, J., Zwitter, T., Balaguer-Nunez, L., Leclerc, N., Morgenthaler, S., Robert, G., and Zucker, S.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Context. Strongly lensed quasars are fundamental sources for cosmology. The Gaia space mission covers the entire sky with the unprecedented resolution of $0.18$" in the optical, making it an ideal instrument to search for gravitational lenses down to the limiting magnitude of 21. Nevertheless, the previous Gaia Data Releases are known to be incomplete for small angular separations such as those expected for most lenses. Aims. We present the Data Processing and Analysis Consortium GravLens pipeline, which was built to analyse all Gaia detections around quasars and to cluster them into sources, thus producing a catalogue of secondary sources around each quasar. We analysed the resulting catalogue to produce scores that indicate source configurations that are compatible with strongly lensed quasars. Methods. GravLens uses the DBSCAN unsupervised clustering algorithm to detect sources around quasars. The resulting catalogue of multiplets is then analysed with several methods to identify potential gravitational lenses. We developed and applied an outlier scoring method, a comparison between the average BP and RP spectra of the components, and we also used an extremely randomised tree algorithm. These methods produce scores to identify the most probable configurations and to establish a list of lens candidates. Results. We analysed the environment of 3 760 032 quasars. A total of 4 760 920 sources, including the quasars, were found within 6" of the quasar positions. This list is given in the Gaia archive. In 87\% of cases, the quasar remains a single source, and in 501 385 cases neighbouring sources were detected. We propose a list of 381 lensed candidates, of which we identified 49 as the most promising. Beyond these candidates, the associate tables in this Focused Product Release allow the entire community to explore the unique Gaia data for strong lensing studies further., Comment: 35 pages, 60 figures, accepted for publication by Astronomy and Astrophysics
Published: 2023
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6. Gaia Focused Product Release: Radial velocity time series of long-period variables

Author: Gaia Collaboration, Trabucchi, M., Mowlavi, N., Lebzelter, T., Lecoeur-Taibi, I., Audard, M., Eyer, L., García-Lario, P., Gavras, P., Holl, B., de Fombelle, G. Jevardat, Nienartowicz, K., Rimoldini, L., Sartoretti, P., Blomme, R., Frémat, Y., Marchal, O., Damerdji, Y., Brown, A. G. A., Guerrier, A., Panuzzo, P., Katz, D., Seabroke, G. M., Benson, K., Haigron, R., Smith, M., Lobel, A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Barbier, A., Biermann, M., Creevey, O. L., Ducourant, C., Evans, D. W., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Mignard, F., Randich, S., Smiljanic, R., Tanga, P., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Cropper, M., Drimmel, R., Lattanzi, M. G., Soubiran, C., van Leeuwen, F., Bakker, J., Castañeda, J., De Angeli, F., Fabricius, C., Fouesneau, M., Galluccio, L., Masana, E., Messineo, R., Nicolas, C., Pailler, F., Riclet, F., Roux, W., Sordo, R., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Berthier, J., Burgess, P. W., Busonero, D., Busso, G., Cánovas, H., Carry, B., Cheek, N., Clementini, G., Davidson, M., de Teodoro, P., Delchambre, L., Dell'Oro, A., Garcia, E. Fraile, Garabato, D., Torres, N. Garralda, Hambly, N. C., Harrison, D. L., Hatzidimitriou, D., Hernández, J., Hodgkin, S. T., Jamal, S., Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Lorca, A., Marrese, P. M., Moitinho, A., Muinonen, K., Campos, M. Nuñez, Oreshina-Slezak, I., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Riello, M., Robin, A. C., Roegiers, T., Sarro, L. M., Schultheis, M., Siopis, C., Sozzetti, A., Utrilla, E., van Leeuwen, M., Weingrill, K., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Altavilla, G., Álvarez, M. A., Alves, J., Anders, F., Anderson, R. I., Antoja, T., Baines, D., Baker, S. G., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bashi, D., Bauchet, N., Baudeau, N., Becciani, U., Bedin, L. R., Bellas-Velidis, I., Bellazzini, M., Beordo, W., Berihuete, A., Bernet, M., Bertolotto, C., Bertone, S., Bianchi, L., Binnenfeld, A., Blazere, A., Boch, T., Bombrun, A., Bouquillon, S., Bragaglia, A., Braine, J., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cannizzo, S., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Carretero, J., Carton, S., Casamiquela, L., Castellani, M., Castro-Ginard, A., Cesare, V., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Collins, R., Contursi, G., Cooper, W. J., Cornez, T., Crosta, M., Crowley, C., Dafonte, C., David, M., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Torres, A., del Peloso, E. F., Delbo, M., Delgado, A., Dharmawardena, T. E., Diakite, S., Diener, C., Distefano, E., Dolding, C., Dsilva, K., Durán, J., Enke, H., Esquej, P., Fabre, C., Fabrizio, M., Faigler, S., Fatović, M., Fedorets, G., Fernández-Hernández, J., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Gai, M., Galinier, M., Garcia-Gutierrez, A., García-Torres, M., Garofalo, A., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., González-Núñez, J., González-Santamaría, I., Gosset, E., Granvik, M., Barrera, V. Gregori, Gutiérrez-Sánchez, R., Haywood, M., Helmer, A., Helmi, A., Henares, K., Hidalgo, S. L., Hilger, T., Hobbs, D., Hottier, C., Huckle, H. E., Jabłońska, M., Jansen, F., Jiménez-Arranz, Ó., Campillo, J. Juaristi, Khanna, S., Kordopatis, G., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kun, M., Lambert, S., Lanza, A. F., Campion, J. -F. Le, Lebreton, Y., Leccia, S., Lecoutre, G., Liao, S., Liberato, L., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Loup, C., Mahy, L., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Pina, D. Marín, Marinoni, S., Marshall, D. J., Lozano, J. Martín, Martín-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Meichsner, J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Munoz, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Nieto, S., Noval, L., Ogden, A., Ordenovic, C., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Panem, C., Payne-Wardenaar, S., Pegoraro, L., Penttilä, A., Pesciullesi, P., Piersimoni, A. M., Pinamonti, M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Pourbaix, D., Prša, A., Pulone, L., Racero, E., Rainer, M., Raiteri, C. M., Ramos, P., Ramos-Lerate, M., Ratajczak, M., Fiorentin, P. Re, Regibo, S., Reylé, C., Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, C., Romero-Gómez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Riera, C. Sarrate, Sciacca, E., Segovia, J. C., Ségransan, D., Shahaf, S., Siebert, A., Siltala, L., Slezak, E., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spina, L., Spitoni, E., Spoto, F., Squillante, L. A., Steele, I. A., Steidelmüller, H., Surdej, J., Szabados, L., Taris, F., Taylor, M. B., Teixeira, R., Tisanić, K., Tolomei, L., Torra, F., Elipe, G. Torralba, Tsantaki, M., Ulla, A., Unger, N., Vanel, O., Vecchiato, A., Vicente, D., Voutsinas, S., Weiler, M., Wyrzykowski, Ł., Zhao, H., Zorec, J., Zwitter, T., Balaguer-Núñez, L., Leclerc, N., Morgenthaler, S., Robert, G., and Zucker, S.
Subjects: Astrophysics - Solar and Stellar Astrophysics
Abstract: The third Gaia Data Release (DR3) provided photometric time series of more than 2 million long-period variable (LPV) candidates. Anticipating the publication of full radial-velocity (RV) in DR4, this Focused Product Release (FPR) provides RV time series for a selection of LPVs with high-quality observations. We describe the production and content of the Gaia catalog of LPV RV time series, and the methods used to compute variability parameters published in the Gaia FPR. Starting from the DR3 LPVs catalog, we applied filters to construct a sample of sources with high-quality RV measurements. We modeled their RV and photometric time series to derive their periods and amplitudes, and further refined the sample by requiring compatibility between the RV period and at least one of the $G$, $G_{\rm BP}$, or $G_{\rm RP}$ photometric periods. The catalog includes RV time series and variability parameters for 9\,614 sources in the magnitude range $6\lesssim G/{\rm mag}\lesssim 14$, including a flagged top-quality subsample of 6\,093 stars whose RV periods are fully compatible with the values derived from the $G$, $G_{\rm BP}$, and $G_{\rm RP}$ photometric time series. The RV time series contain a mean of 24 measurements per source taken unevenly over a duration of about three years. We identify the great most sources (88%) as genuine LPVs, with about half of them showing a pulsation period and the other half displaying a long secondary period. The remaining 12% consists of candidate ellipsoidal binaries. Quality checks against RVs available in the literature show excellent agreement. We provide illustrative examples and cautionary remarks. The publication of RV time series for almost 10\,000 LPVs constitutes, by far, the largest such database available to date in the literature. The availability of simultaneous photometric measurements gives a unique added value to the Gaia catalog (abridged), Comment: 36 pages, 38 figures
Published: 2023

7. Gaia Data Release 3: Summary of the content and survey properties

Author: Gaia Collaboration, Vallenari, A., Brown, A. G. A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Biermann, M., Creevey, O. L., Ducourant, C., Evans, D. W., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U. L., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Drimmel, R., Jansen, F., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Cacciari, C., Castañeda, J., De Angeli, F., Fabricius, C., 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., Sordoørcit, R., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., 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., Davidson, M., de Teodoro, P., Campos, M. Nuñez, Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J., Fraile, E., Garabato, D., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Reylé, C., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anders, F., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Becciani, U., Bellazzini, M., Berihuete, A., Bernet, M., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Blazere, A., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, M., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Torres, A., del Peloso, E. F., del Pozo, E., Delbo, M., Delgado, A., Delisle, J. -B., Demouchy, C., Dharmawardena, T. E., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Edvardsson, B., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fienga, A., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Gavel, A., Gavras, P., Gerlach, E., Geyer, R., 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., Sarmiento, M. H., Hidalgo, S. L., Hilger, T., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jardine, K., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Jorissen, A., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kontizas, M., Kordopatis, G., Korn, A. J., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Peñalosa, Penttilä, A., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Rambaux, N., Ramos, P., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Richards, P. J., Diaz, C. Rios, Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylo, M. B., Teixeira, R., Tolomei, L., Tonello, N., Torra, F., Torra, J., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, L., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the third data release of the European Space Agency's Gaia mission, GDR3. The GDR3 catalogue is the outcome of the processing of raw data collected with the Gaia instruments during the first 34 months of the mission by the Gaia Data Processing and Analysis Consortium. The GDR3 catalogue contains the same source list, celestial positions, proper motions, parallaxes, and broad band photometry in the G, G$_{BP}$, and G$_{RP}$ pass-bands already present in the Early Third Data Release. GDR3 introduces an impressive wealth of new data products. More than 33 million objects in the ranges $G_{rvs} < 14$ and $3100
Published: 2022
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8. Gaia Data Release 3: Reflectance spectra of Solar System small bodies

Author: Gaia Collaboration, Galluccio, L., Delbo, M., De Angeli, F., Pauwels, T., Tanga, P., Mignard, F., Cellino, A., Brown, A. G. A., Muinonen, K., Penttila, A., Jordan, S., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Biermann, M., Creevey, O. L., Ducourant, C., Evans, D. W., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U. L., Lindegren, L., Luri, X., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Drimmel, R., Jansen, F., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Cacciari, C., Castaneda, J., Fabricius, C., Fouesneau, M., Frémat, Y., 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., Portell, J., Teyssier, D., 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., Cheek, N., Clementini, G., Damerdji, Y., Davidson, M., de Teodoro, P., Campos, M. Nunez, Delchambre, L., Oro, A. Dell, Esquej, P., Fernández-Hernández, J., Fraile, E., Garabato, D., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janssen, K., de Fombelle, G. Jevardat, Krone-Martins, A., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Osborne, P., Pancino, E., Recio-Blanco, A., Reylé, C., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baines, D., Baker, S. G., Balaguer-Núnez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Becciani, U., Bellazzini, M., Berihuete, A., Bernet, M., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Torres, A., del Peloso, E. F., del Pozo, E., Delgado, A., Delisle, J. -B., Demouchy, C., Dharmawardena, T. E., Diakite, S., Diener, C., Distefano, E., Dolding, C., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Gavel, A., Gavras, P., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., González-Núnez, 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., Sarmiento, M. H., Hidalgo, S. L., Hadczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jardine, K., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kordopatis, G., Korn, A. J., Kospál, A, Kostrzewa-Rutkowska, Z., Kruszynska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrom, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocana, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Penalosa, Petit, J. -M., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Prsa, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Ramos, P., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Richards, P. J., Diaz, C. Rios, Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núnez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santovena, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M. B., Teixeira, R., Tolomei, L., Tonello, N., Torra, F., Torra, J., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, L., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., and Zwitter, T.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: The Gaia mission of the European Space Agency (ESA) has been routinely observing Solar System objects (SSOs) since the beginning of its operations in August 2014. The Gaia data release three (DR3) includes, for the first time, the mean reflectance spectra of a selected sample of 60 518 SSOs, primarily asteroids, observed between August 5, 2014, and May 28, 2017. Each reflectance spectrum was derived from measurements obtained by means of the Blue and Red photometers (BP/RP), which were binned in 16 discrete wavelength bands. We describe the processing of the Gaia spectral data of SSOs, explaining both the criteria used to select the subset of asteroid spectra published in Gaia DR3, and the different steps of our internal validation procedures. In order to further assess the quality of Gaia SSO reflectance spectra, we carried out external validation against SSO reflectance spectra obtained from ground-based and space-borne telescopes and available in the literature. For each selected SSO, an epoch reflectance was computed by dividing the calibrated spectrum observed by the BP/RP at each transit on the focal plane by the mean spectrum of a solar analogue. The latter was obtained by averaging the Gaia spectral measurements of a selected sample of stars known to have very similar spectra to that of the Sun. Finally, a mean of the epoch reflectance spectra was calculated in 16 spectral bands for each SSO. The agreement between Gaia mean reflectance spectra and those available in the literature is good for bright SSOs, regardless of their taxonomic spectral class. We identify an increase in the spectral slope of S-type SSOs with increasing phase angle. Moreover, we show that the spectral slope increases and the depth of the 1 um absorption band decreases for increasing ages of S-type asteroid families., Comment: 30 pages, 26 figures
Published: 2022
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9. Gaia Data Release 3 Properties and validation of the radial velocities

Author: Katz, D., Sartoretti, P., Guerrier, A., Panuzzo, P., Seabroke, G. M., Thévenin, F., Cropper, M., Benson, K., Blomme, R., Haigron, R., Marchal, O., Smith, M., Baker, S., Chemin, L., Damerdji, Y., David, M., Dolding, C., Frémat, Y., Gosset, E., Janßen, K., Jasniewicz, G., Lobel, A., Plum, G., Samaras, N., Snaith, O., Soubiran, C., Vanel, O., Zwitter, T., Antoja, T., Arenou, F., Babusiaux, C., Brouillet, N., Caffau, E., Di Matteo, P., Fabre, C., Fabricius, C., Frakgoudi, F., Haywood, M., Huckle, H. E., Hottier, C., Lasne, Y., Leclerc, N., Mastrobuono-Battisti, A., Royer, F., Teyssier, D., Zorec, J., Crifo, F., Piccolo, A. Jean-Antoine, Turon, C., and Viala, Y.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Gaia Data Release 3 (Gaia DR3) contains the second release of the combined radial velocities. It is based on the spectra collected during the first 34 months of the nominal mission. The longer time baseline and the improvements of the pipeline made it possible to push the processing limit, from Grvs = 12 in Gaia DR2, to Grvs = 14 mag. In this article, we describe the new functionalities implemented for Gaia DR3, the quality filters applied during processing and post-processing and the properties and performance of the published velocities. For Gaia DR3, several functionalities were upgraded or added. (Abridged) Gaia DR3 contains the combined radial velocities of 33 812 183 stars. With respect to Gaia DR2, the interval of temperature has been expanded from Teff \in [3600, 6750] K to Teff \in [3100, 14500] K for the bright stars ( Grvs \leq 12 mag) and [3100, 6750] K for the fainter stars. The radial velocities sample a significant part of the Milky Way: they reach a few kilo-parsecs beyond the Galactic centre in the disc and up to about 10-15 kpc vertically into the inner halo. The median formal precision of the velocities is of 1.3 km/s at Grvs = 12 and 6.4 km/s at Grvs = 14 mag. The velocity zero point exhibits a small systematic trend with magnitude starting around Grvs = 11 mag and reaching about 400 m/s at Grvs = 14 mag. A correction formula is provided, which can be applied to the published data. The Gaia DR3 velocity scale is in satisfactory agreement with APOGEE, GALAH, GES and RAVE, with systematic differences that mostly do not exceed a few hundreds m/s. The properties of the radial velocities are also illustrated with specific objects: open clusters, globular clusters as well as the Large Magellanic Cloud (LMC). For example, the precision of the data allows to map the line-of-sight rotational velocities of the globular cluster 47 Tuc and of the LMC., Comment: Sumitted to A&A
Published: 2022
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10. Gaia Data Release 3: Mapping the asymmetric disc of the Milky Way

Author: Gaia Collaboration, Drimmel, R., Romero-Gomez, M., Chemin, L., Ramos, P., Poggio, E., Ripepi, V., Andrae, R., Blomme, R., Cantat-Gaudin, T., Castro-Ginard, A., Clementini, G., Figueras, F., Fouesneau, M., Fremat, Y., Jardine, K., Khanna, S., Lobel, A., Marshall, D. J., Muraveva, T., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Biermann, M., Creevey, O. L., Ducourant, C., Evans, D. W., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U. L., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Jansen, F., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Cacciari, C., Castañeda, J., De Angeli, F., Fabricius, C., 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., Sordoørcit, R., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Audard, M., Bellas-Velidis, I., Benson, K., Berthier, J., Burgess, P. W., Busonero, D., Busso, G., Cánovas, H., Carry, B., Cellino, A., Cheek, N., Damerdji, Y., Davidson, M., de Teodoro, P., Campos, M. Nuñez, Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J., Fraile, E., Garabato, D., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Reylé, C., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anders, F., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Becciani, U., Bellazzini, M., Berihuete, A., Bernet, M., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Blazere, A., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Casamiquela, L., Castellani, M., Chaoul, L., Charlot, P., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, M., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Torres, A., del Peloso, E. F., del Pozo, E., Delbo, M., Delgado, A., Delisle, J. -B., Demouchy, C., Dharmawardena, T. E., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Edvardsson, B., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fienga, A., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Gavel, A., Gavras, P., Gerlach, E., Geyer, R., 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., Sarmiento, M. H., Hidalgo, S. L., Hilger, T., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Jorissen, A., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Kontizas, M., Kordopatis, G., Korn, A. J., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., Polo, L. Martin, Martín-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Peñalosa, Penttilä, A., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Rambaux, N., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Richards, P. J., Diaz, C. Rios, Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylo, M. B., Teixeira, R., Tolomei, L., Tonello, N., Torra, F., Torra, J., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, L., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: With the most recent Gaia data release the number of sources with complete 6D phase space information (position and velocity) has increased to well over 33 million stars, while stellar astrophysical parameters are provided for more than 470 million sources, in addition to the identification of over 11 million variable stars. Using the astrophysical parameters and variability classifications provided in Gaia DR3, we select various stellar populations to explore and identify non-axisymmetric features in the disc of the Milky Way in both configuration and velocity space. Using more about 580 thousand sources identified as hot OB stars, together with 988 known open clusters younger than 100 million years, we map the spiral structure associated with star formation 4-5 kpc from the Sun. We select over 2800 Classical Cepheids younger than 200 million years, which show spiral features extending as far as 10 kpc from the Sun in the outer disc. We also identify more than 8.7 million sources on the red giant branch (RGB), of which 5.7 million have line-of-sight velocities, allowing the velocity field of the Milky Way to be mapped as far as 8 kpc from the Sun, including the inner disc. The spiral structure revealed by the young populations is consistent with recent results using Gaia EDR3 astrometry and source lists based on near infrared photometry, showing the Local (Orion) arm to be at least 8 kpc long, and an outer arm consistent with what is seen in HI surveys, which seems to be a continuation of the Perseus arm into the third quadrant. Meanwhile, the subset of RGB stars with velocities clearly reveals the large scale kinematic signature of the bar in the inner disc, as well as evidence of streaming motions in the outer disc that might be associated with spiral arms or bar resonances. (abridged), Comment: 35 pages, 27 figures, accepted for publication in A&A special Gaia DR3 issue. V2: abstract completed. V3: complete author list and link to data: https://drive.google.com/drive/u/1/folders/1yOJPjYmM7QK5XVsqaiSOTuwDQNti2LlZ
Published: 2022
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11. Gaia Data Release 3: Pulsations in main sequence OBAF-type stars

Author: Gaia Collaboration, De Ridder, J., Ripepi, V., Aerts, C., Palaversa, L., Eyer, L., Holl, B., Audard, M., Rimoldini, L., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Biermann, M., Creevey, O. L., Ducourant, C., Evans, D. W., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U. L., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Drimmel, R., Jansen, F., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Cacciari, C., Castañeda, J., De Angeli, F., Fabricius, C., 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., Portell, J., Teyssier, D., Altmann, M., Andrae, R., 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., Davidson, M., de Teodoro, P., Campos, M. Nuñez, Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J., Fraile, E., Garabato, D., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hernández, J., Hestroffer, D., Hilger, T., Hodgkin, S. T., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Reylé, C., Riello, M., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anders, F., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Becciani, U., Bellazzini, M., Berihuete, A., Bernet, M., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., de Laverny, P., De Luise, F., De March, R., de Souza, R., de Torres, A., del Peloso, E. F., del Pozo, E., Delbo, M., Delgado, A., Delisle, J. -B., Demouchy, C., Dharmawardena, T. E., Diakite, S., Diener, C., Distefano, E., Dolding, C., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Gavel, A., Gavras, P., Gerlach, E., Geyer, R., 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., Sarmiento, M. H., Hidalgo, S. L., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jardine, K., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kordopatis, G., Korn, A. J., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Peñalosa, Penttilä, A., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Ramos, P., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Richards, P. J., Diaz, C. Rios, Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M. B., Teixeira, R., Tolomei, L., Tonello, N., Torra, F., Torra, J., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., and Zwitter, T.
Subjects: Astrophysics - Solar and Stellar Astrophysics
Abstract: The third Gaia data release provides photometric time series covering 34 months for about 10 million stars. For many of those stars, a characterisation in Fourier space and their variability classification are also provided. This paper focuses on intermediate- to high-mass (IHM) main sequence pulsators M >= 1.3 Msun) of spectral types O, B, A, or F, known as beta Cep, slowly pulsating B (SPB), delta Sct, and gamma Dor stars. These stars are often multi-periodic and display low amplitudes, making them challenging targets to analyse with sparse time series. All datasets used in this analysis are part of the Gaia DR3 data release. The photometric time series were used to perform a Fourier analysis, while the global astrophysical parameters necessary for the empirical instability strips were taken from the Gaia DR3 gspphot tables, and the vsini data were taken from the Gaia DR3 esphs tables. We show that for nearby OBAF-type pulsators, the Gaia DR3 data are precise and accurate enough to pinpoint them in the Hertzsprung-Russell diagram. We find empirical instability strips covering broader regions than theoretically predicted. In particular, our study reveals the presence of fast rotating gravity-mode pulsators outside the strips, as well as the co-existence of rotationally modulated variables inside the strips as reported before in the literature. We derive an extensive period-luminosity relation for delta Sct stars and provide evidence that the relation features different regimes depending on the oscillation period. Finally, we demonstrate how stellar rotation attenuates the amplitude of the dominant oscillation mode of delta Sct stars.
Published: 2022
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12. Gaia Data Release 3: A Golden Sample of Astrophysical Parameters

Author: Gaia Collaboration, Creevey, O. L., Sarro, L. M., Lobel, A., Pancino, E., Andrae, R., Smart, R. L., Clementini, G., Heiter, U., Korn, A. J., Fouesneau, M., Frémat, Y., De Angeli, F., Vallenari, A., Harrison, D. L., Thévenin, F., Reylé, C., Sordo, R., Garofalo, A., Brown, A. G. A., Eyer, L., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Biermann, M., Ducourant, C., Evans, D. W., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U. L., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Drimmel, R., Jansen, F., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Cacciari, C., Castañeda, J., Fabricius, C., Galluccio, L., Guerrier, A., Masana, E., Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Seabroke, G. M., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., 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., Damerdji, Y., Davidson, M., de Teodoro, P., Campos, M. Nuñez, Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J., Fraile, E., Garabato, D., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Osborne, P., Pauwels, T., Recio-Blanco, A., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anders, F., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Becciani, U., Bellazzini, M., Berihuete, A., Bernet, M., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Torres, A., del Peloso, E. F., del Pozo, E., Delbo, M., Delgado, A., Delisle, J. -B., Demouchy, C., Dharmawardena, T. E., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Gavel, A., Gavras, P., Gerlach, E., Geyer, R., 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., Sarmiento, M. H., Hidalgo, S. L., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jardine, K., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kordopatis, G., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Peñalosa, Penttilä, A., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Ramos, P., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Richards, P. J., Diaz, C. Rios, Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M. B., Teixeira, R., Tolomei, L., Tonello, N., Torra, F., Torra, J., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., and Zwitter, T.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Gaia Data Release 3 (DR3) provides a wealth of new data products for the astronomical community to exploit, including astrophysical parameters for a half billion stars. In this work we demonstrate the high quality of these data products and illustrate their use in different astrophysical contexts. We query the astrophysical parameter tables along with other tables in Gaia DR3 to derive the samples of the stars of interest. We validate our results by using the Gaia catalogue itself and by comparison with external data. We have produced six homogeneous samples of stars with high quality astrophysical parameters across the HR diagram for the community to exploit. We first focus on three samples that span a large parameter space: young massive disk stars (~3M), FGKM spectral type stars (~3M), and UCDs (~20K). We provide these sources along with additional information (either a flag or complementary parameters) as tables that are made available in the Gaia archive. We furthermore identify 15740 bone fide carbon stars, 5863 solar-analogues, and provide the first homogeneous set of stellar parameters of the Spectro Photometric Standard Stars. We use a subset of the OBA sample to illustrate its usefulness to analyse the Milky Way rotation curve. We then use the properties of the FGKM stars to analyse known exoplanet systems. We also analyse the ages of some unseen UCD-companions to the FGKM stars. We additionally predict the colours of the Sun in various passbands (Gaia, 2MASS, WISE) using the solar-analogue sample., Comment: 35 pages, (incl 6 pages references, acknowledgements, affiliations), 37 figures, A&A accepted
Published: 2022
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13. Gaia Data Release 3: The extragalactic content

Author: Gaia Collaboration, Bailer-Jones, C. A. L., Teyssier, D., Delchambre, L., Ducourant, C., Garabato, D., Hatzidimitriou, D., Klioner, S. A., Rimoldini, L., Bellas-Velidis, I., Carballo, R., Carnerero, M. I., Diener, C., Fouesneau, M., Galluccio, L., Gavras, P., Krone-Martins, A., Raiteri, C. M., Teixeira, R., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Biermann, M., Creevey, O. L., Evans, D. W., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Lammers, U. L., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N. A., Bastian, U., Drimmel, R., Jansen, F., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Cacciari, C., Castañeda, J., De Angeli, F., Fabricius, C., Frémat, Y., 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., Portell, J., Altmann, M., Andrae, R., Audard, M., 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., Davidson, M., de Teodoro, P., Campos, M. Nuñez, Dell'Oro, A., Esquej, P., Fernández-Hernández, J., Fraile, E., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Reylé, C., Riello, M., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Becciani, U., Bellazzini, M., Berihuete, A., Bernet, M., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carlucci, T., Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Torres, A., del Peloso, E. F., del Pozo, E., Delbo, M., Delgado, A., Delisle, J. -B., Demouchy, C., Dharmawardena, T. E., Diakite, S., Distefano, E., Dolding, C., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Gavel, A., Gerlach, E., Geyer, R., 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., Hauser, M., Haywood, M., Helmer, A., Helmi, A., Sarmiento, M. H., Hidalgo, S. L., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jardine, K., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kontizas, M., Kordopatis, G., Korn, A. J., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Peñalosa, Penttilä, A., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Ramos, P., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Richards, P. J., Diaz, C. Rios, Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M. S., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M. B., Tolomei, L., Tonello, N., Torra, F., Torra, J., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The Gaia Galactic survey mission is designed and optimized to obtain astrometry, photometry, and spectroscopy of nearly two billion stars in our Galaxy. Yet as an all-sky multi-epoch survey, Gaia also observes several million extragalactic objects down to a magnitude of G~21 mag. Due to the nature of the Gaia onboard selection algorithms, these are mostly point-source-like objects. Using data provided by the satellite, we have identified quasar and galaxy candidates via supervised machine learning methods, and estimate their redshifts using the low resolution BP/RP spectra. We further characterise the surface brightness profiles of host galaxies of quasars and of galaxies from pre-defined input lists. Here we give an overview of the processing of extragalactic objects, describe the data products in Gaia DR3, and analyse their properties. Two integrated tables contain the main results for a high completeness, but low purity (50-70%), set of 6.6 million candidate quasars and 4.8 million candidate galaxies. We provide queries that select purer sub-samples of these containing 1.9 million probable quasars and 2.9 million probable galaxies (both 95% purity). We also use high quality BP/RP spectra of 43 thousand high probability quasars over the redshift range 0.05-4.36 to construct a composite quasar spectrum spanning restframe wavelengths from 72-100 nm., Comment: Accepted to A&A
Published: 2022
Full Text: View/download PDF

14. Gaia Data Release 3: Stellar multiplicity, a teaser for the hidden treasure

Author: Gaia Collaboration, Arenou, F., Babusiaux, C., Barstow, M. A., Faigler, S., Jorissen, A., Kervella, P., Mazeh, T., Mowlavi, N., Panuzzo, P., Sahlmann, J., Shahaf, S., Sozzetti, A., Bauchet, N., Damerdji, Y., Gavras, P., Giacobbe, P., Gosset, E., Halbwachs, J. -L., Holl, B., Lattanzi, M. G., Leclerc, N., Morel, T., Pourbaix, D., Fiorentin, P. Re, Sadowski, G., Ségransan, D., Siopis, C., Teyssier, D., Zwitter, T., Planquart, L., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Biermann, M., Creevey, O. L., Ducourant, C., Evans, D. W., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U. L., Lindegren, L., Luri, X., Mignard, F., Panem, C., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N. A., Bailer-Jones, C. A. L., Bastian, U., Drimmel, R., Jansen, F., Katz, D., van Leeuwen, F., Bakker, J., Cacciari, C., Castañeda, J., De Angeli, F., Fabricius, C., Fouesneau, M., Frémat, Y., Galluccio, L., Guerrier, A., Heiter, U., Masana, E., Messineo, R., Nicolas, C., Nienartowicz, K., Pailler, F., Riclet, F., Roux, W., Seabroke, G. M., Sordo, R., Thévenin, F., Gracia-Abril, G., Portell, J., 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., Davidson, M., de Teodoro, P., Campos, M. Nuñez, Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J., Fraile, E., Garabato, D., García-Lario, P., Haigron, R., Hambly, N. C., Harrison, D. L., Hernández, J., Hestroffer, D., Hodgkin, S. T., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Reylé, C., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Sarro, L. M., Smith, M., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anders, F., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Bartolomé, S., Bassilana, J. -L., Becciani, U., Bellazzini, M., Berihuete, A., Bernet, M., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Blazere, A., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Torres, A., del Peloso, E. F., del Pozo, E., Delbo, M., Delgado, A., Delisle, J. -B., Demouchy, C., Dharmawardena, T. E., Diakite, S., Diener, C., Distefano, E., Dolding, C., Enke, H., Fabre, C., Fabrizio, M., Fedorets, G., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Gavel, A., Gerlach, E., Geyer, R., 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., Sarmiento, M. H., Hidalgo, S. L., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jardine, K., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Khanna, S., Kordopatis, G., Korn, A. J., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Marton, G., Mary, N., Masip, A., Massari, D., Mastrobuono-Battisti, A., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morris, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Peñalosa, Penttilä, A., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Ramos, P., Ramos-Lerate, M., Regibo, S., Richards, P. J., Diaz, C. Rios, Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Núñez, A. Sáez, Sellés, A. Sagristà, Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M. S., Sciacca, E., Segol, M., Segovia, J. C., Semeux, D., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M. B., Teixeira, R., Tolomei, L., Tonello, N., Torra, F., Torra, J., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., and Zucker, S.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The Gaia DR3 Catalogue contains for the first time about eight hundred thousand solutions with either orbital elements or trend parameters for astrometric, spectroscopic and eclipsing binaries, and combinations of them. This paper aims to illustrate the huge potential of this large non-single star catalogue. Using the orbital solutions together with models of the binaries, a catalogue of tens of thousands of stellar masses, or lower limits, partly together with consistent flux ratios, has been built. Properties concerning the completeness of the binary catalogues are discussed, statistical features of the orbital elements are explained and a comparison with other catalogues is performed. Illustrative applications are proposed for binaries across the H-R diagram. The binarity is studied in the RGB/AGB and a search for genuine SB1 among long-period variables is performed. The discovery of new EL CVn systems illustrates the potential of combining variability and binarity catalogues. Potential compact object companions are presented, mainly white dwarf companions or double degenerates, but one candidate neutron star is also presented. Towards the bottom of the main sequence, the orbits of previously-suspected binary ultracool dwarfs are determined and new candidate binaries are discovered. The long awaited contribution of Gaia to the analysis of the substellar regime shows the brown dwarf desert around solar-type stars using true, rather than minimum, masses, and provides new important constraints on the occurrence rates of substellar companions to M dwarfs. Several dozen new exoplanets are proposed, including two with validated orbital solutions and one super-Jupiter orbiting a white dwarf, all being candidates requiring confirmation. Beside binarity, higher order multiple systems are also found., Comment: 60 pages, 60 figures. Accepted for publication in Astronomy & Astrophysics (2022-06-09). The catalogue of binary masses is available for download from the ESA Gaia DR3 Archive and will be available from the CDS/VizieR service
Published: 2022
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15. Gaia Data Release 3: Chemical cartography of the Milky Way

Author: Gaia Collaboration, Recio-Blanco, A., Kordopatis, G., de Laverny, P., Palicio, P. A., Spagna, A., Spina, L., Katz, D., Fiorentin, P. Re, Poggio, E., McMillan, P. J., Vallenari, A., Lattanzi, M. G., Seabroke, G. M., Casamiquela, L., Bragaglia, A., Antoja, T., Bailer-Jones, C. A. L., Andrae, R., Fouesneau, M., Cropper, M., Cantat-Gaudin, T., Heiter, U., Bijaoui, A., Brown, A. G. A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Biermann, M., Creevey, O. L., Ducourant, C., Evans, D. W., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Klioner, S. A., Lammers, U. L., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Tanga, P., Walton, N. A., Bastian, U., Drimmel, R., Jansen, F., van Leeuwen, F., Bakker, J., Cacciari, C., Castañeda, J., De Angeli, F., Fabricius, C., Frémat, Y., Galluccio, L., Guerrier, A., Masana, E., Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Sordo, R., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., 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., Davidson, M., de Teodoro, P., Campos, M. Nuñez, Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J., Fraile, E., Garabato, D., García-Lario, P., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Reylé, C., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anders, F., Anderson, R. I., Varela, E. Anglada, Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Becciani, U., Bellazzini, M., Berihuete, A., Bernet, M., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Castellani, M., Castro-Ginard, A., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Torres, A., del Peloso, E. F., del Pozo, E., Delbo, M., Delgado, A., Delisle, J. -B., Demouchy, C., Dharmawardena, T. E., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Edvardsson, B., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Gavel, A., Gavras, P., Gerlach, E., Geyer, R., 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., Sarmiento, M. H., Hidalgo, S. L., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jardine, K., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Korn, A. J., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., 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., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palaversa, L., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Peñalosa, Penttilä, A., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Ramos, P., Ramos-Lerate, M., Regibo, S., Richards, P. J., Diaz, C. Rios, Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M. B., Teixeira, R., Tolomei, L., Tonello, N., Torra, F., Torra, J., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract: Gaia DR3 opens a new era of all-sky spectral analysis of stellar populations thanks to the nearly 5.6 million stars observed by the RVS and parametrised by the GSP-spec module. The all-sky Gaia chemical cartography allows a powerful and precise chemo-dynamical view of the Milky Way with unprecedented spatial coverage and statistical robustness. First, it reveals the strong vertical symmetry of the Galaxy and the flared structure of the disc. Second, the observed kinematic disturbances of the disc -- seen as phase space correlations -- and kinematic or orbital substructures are associated with chemical patterns that favour stars with enhanced metallicities and lower [alpha/Fe] abundance ratios compared to the median values in the radial distributions. This is detected both for young objects that trace the spiral arms and older populations. Several alpha, iron-peak elements and at least one heavy element trace the thin and thick disc properties in the solar cylinder. Third, young disc stars show a recent chemical impoverishment in several elements. Fourth, the largest chemo-dynamical sample of open clusters analysed so far shows a steepening of the radial metallicity gradient with age, which is also observed in the young field population. Finally, the Gaia chemical data have the required coverage and precision to unveil galaxy accretion debris and heated disc stars on halo orbits through their [alpha/Fe] ratio, and to allow the study of the chemo-dynamical properties of globular clusters. Gaia DR3 chemo-dynamical diagnostics open new horizons before the era of ground-based wide-field spectroscopic surveys. They unveil a complex Milky Way that is the outcome of an eventful evolution, shaping it to the present day (abridged)., Comment: Astronomy and Astrophysics (accepted, in press)
Published: 2022
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16. Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)

Author: Gaia Collaboration, 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., Hilger, T., Hobbs, D., Lammers, U. L., McMillan, P. J., Steidelmüller, H., Teyssier, D., Raiteri, C. M., Bartolomé, S., Bernet, M., Castañeda, J., Clotet, M., Davidson, M., Fabricius, C., Torres, N. Garralda, González-Vidal, J. J., Portell, J., Rowell, N., Torra, F., Torra, J., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Arenou, F., Babusiaux, C., Creevey, O. L., Ducourant, C., Evans, D. W., Eyer, L., Guerra, R., Hutton, A., Jordi, C., Luri, X., Panem, C., 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., Campos, M. Nuñez, Delchambre, L., Dell'Oro, A., Esquej, P., Fernández-Hernández, J., 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., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Marchal, O., Marrese, P. M., Moitinho, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Reylé, C., Riello, M., Rimoldini, L., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Utrilla, E., van Leeuwen, M., Abbas, U., Ábrahám, P., Aramburu, A. Abreu, Aerts, C., Aguado, J. J., Ajaj, M., Aldea-Montero, F., Altavilla, G., Álvarez, M. A., Alves, J., Anderson, R. I., Varela, E. Anglada, Antoja, T., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bassilana, J. -L., Bauchet, N., Becciani, U., Bellazzini, M., Berihuete, A., Bertone, S., Bianchi, L., Binnenfeld, A., Blanco-Cuaresma, S., Boch, T., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Brugaletta, E., Bucciarelli, B., Burlacu, A., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I., Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Chaoul, L., Charlot, P., Chemin, L., Chiaramida, V., Chiavassa, A., Chornay, N., Comoretto, G., Contursi, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Cropper, M., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, P., de Laverny, P., De Luise, F., 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., Diakite, S., Diener, C., Distefano, E., Dolding, C., Enke, H., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fienga, A., Figueras, F., Fournier, Y., Fouron, C., Fragkoudi, F., Gai, M., Garcia-Gutierrez, A., Garcia-Reinaldos, M., García-Torres, M., Garofalo, A., Gavel, A., Gavras, P., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., González-Núñez, J., González-Santamaría, I., Granvik, M., Guillout, P., Guiraud, J., Gutiérrez-Sánchez, R., Guy, L. P., Hatzidimitriou, D., Hauser, M., Haywood, M., Helmer, A., Helmi, A., Sarmiento, M. H., Hidalgo, S. L., Hładczuk, N., Holland, G., Huckle, H. E., Jardine, K., Jasniewicz, G., Piccolo, A. Jean-Antoine, Jiménez-Arranz, Ó., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kordopatis, G., Korn, A. J., Kóspál, Á, Kostrzewa-Rutkowska, Z., Kruszyńska, K., Kun, M., Laizeau, P., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E. L., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Lorca, A., Loup, C., Pardo, P. Madrero, Romeo, A. Magdaleno, Managau, S., Mann, R. G., Manteiga, M., Marchant, J. M., Marconi, M., Marcos, J., Santos, M. M. S. Marcos, Pina, D. Marín, Marinoni, S., Marocco, F., 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., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Monari, G., Monguió, M., Montegriffo, P., Montero, A., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morris, D., Muraveva, T., Murphy, C. P., Musella, I., Nagy, Z., Noval, L., Ocaña, F., Ogden, A., Ordenovic, C., Osinde, J. O., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Pallas-Quintela, L., Panahi, A., Payne-Wardenaar, S., Esteller, X. Peñalosa, Penttilä, A., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Rambaux, N., Ramos, P., Fiorentin, P. Re, Regibo, S., Richards, P. J., Diaz, C. Rios, Ripepi, V., Riva, A., Rix, H. -W., Rixon, G., Robichon, N., Robin, A. C., Robin, C., Roelens, M., Rogues, H. R. O., Rohrbasser, L., Romero-Gómez, M., Royer, F., Mieres, D. Ruz, Rybicki, K. A., Sadowski, G., Núñez, A. Sáez, Sellés, A. Sagristà, Sahlmann, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Silvelo, A., Slezak, E., Slezak, I., Smart, R. L., Snaith, O. N., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spina, L., Spoto, F., Steele, I. A., Stephenson, C. A., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Taris, F., Taylor, M. B., Teixeira, R., Tolomei, L., Tonello, N., Elipe, G. Torralba, Trabucchi, M., Tsounis, A. T., Turon, C., Ulla, A., Unger, N., Vaillant, M. V., van Dillen, E., van Reeven, W., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., and Zwitter, T.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: 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. We describe the construction of Gaia-CRF3, and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasars (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). The 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 to 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 ${\mu}$as 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 exceeds 4 mas in either coordinate for 127 sources. We outline the future of the Gaia-CRF in the next Gaia data releases.
Published: 2022
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17. TOPoS VI. The metal-weak tail of the metallicity distribution functions of the Milky Way and of the Gaia-Sausage-Enceladus structure

Author: Bonifacio, P, Monaco, L, Salvadori, S, Caffau, E, Spite, M, Sbordone, L, Spite, F, Ludwig, H. -G, Di Matteo, P, Haywood, M, François, P, Koch-Hansen, A. J., Christlieb, N, and Zaggia, S
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Context. The TOPoS project has the goal to find and analyse Turn-Off (TO) stars of extremely low metallicity. To select the targets for spectroscopic follow-up at high spectral resolution, we have relied on low-resolution spectra from the Sloan Digital Sky Survey. Aims. In this paper we use the metallicity estimates we have obtained from our analysis of the SDSS spectra to construct the metallicity distribution function (MDF) of the Milky Way, with special emphasis on its metal-weak tail. The goal is to provide the underlying distribution out of which the TOPoS sample was extracted. Methods. We make use of SDSS photometry, Gaia photometry and distance estimates derived from the Gaia parallaxes to derive a metallicity estimate for a large sample of over 24 million TO stars. This sample is used to derive the metallicity bias of the sample for which SDSS spectra are available. Results. We determined that the spectroscopic sample is strongly biased in favour of metal-poor stars, as intended. A comparison with the unbiased photometric sample allows to correct for the selection bias. We select a sub-sample of stars with reliable parallaxes for which we combine the SDSS radial velocities with Gaia proper motions and parallaxes to compute actions and orbital parameters in the Galactic potential. This allows us to characterize the stars dynamically, and in particular to select a sub-sample that belongs to the Gaia-Sausage-Enceladus (GSE) accretion event. We are thus able to provide also the MDF of GSE. Conclusions. The metal-weak tail derived in our study is very similar to that derived in the H3 survey and in the Hamburg/ESO Survey. This allows us to average the three MDFs and provide an error bar for each metallicity bin. Inasmuch the GSE structure is representative of the progenitor galaxy that collided with the Milky Way, that galaxy appears to be strongly deficient in metal-poor stars compared to the Milky Way, suggesting that the metal-weak tail of the latter has been largely formed by accretion of low mass galaxies rather than massive galaxies, such as the GSE progenitor., Comment: Astronomy and Astrophysics - A\&A, EDP Sciences, in press
Published: 2021
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18. Radial structure and formation of the Milky Way disc

Author: Katz, D., Gomez, A., Haywood, M., Snaith, O., and Di Matteo, P.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The formation of the Galactic disc is an enthusiastically debated issue. Numerous studies and models seek to identify the dominant physical process(es) that shaped its observed properties. Taking advantage of the improved coverage of the inner Milky Way provided by the SDSS DR16 APOGEE catalogue and of the ages published in the APOGEE-AstroNN Value Added Catalogue (VAC), we examine the radial evolution of the chemical and age properties of the Galactic stellar disc, with the aim to better constrain its formation. Using a sample of 199,307 giant stars with precise APOGEE abundances and APOGEE-astroNN ages, selected in a +/-2 kpc layer around the galactic plane, we assess the dependency with guiding radius of: (i) the median metallicity, (ii) the ridge lines of the [Fe/H]-[Mg/Fe] and age-[Mg/Fe] distributions and (iii) the Age Distribution Function (ADF). The giant star sample allows us to probe the radial behaviour of the Galactic disc from Rg = 0 to 14-16 kpc. The thick disc [Fe/H]-[Mg/Fe] ridge lines follow closely grouped parallel paths, supporting the idea that the thick disc did form from a well-mixed medium. However, the ridge lines present a small drift in [Mg/Fe], which decreases with increasing guiding radius. At sub-solar metallicity, the intermediate and outer thin disc [Fe/H]-[Mg/Fe] ridge lines follow parallel sequences shifted to lower metallicity as the guiding radius increases. We interpret this pattern, as the signature of a dilution of the inter-stellar medium from Rg~6 kpc to the outskirt of the disc, which occured before the onset of the thin disc formation. The APOGEE-AstroNN VAC provides stellar ages for statistically significant samples of thin disc stars from the Galactic centre up to Rg~14 kpc. An important result provided by this dataset, is that the thin disc presents evidence of an inside-out formation up to R_g~10-12 kpc.(Abridged), Comment: 18 pages, 21 figures, submitted to A&A on 29/01/2021
Published: 2021
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19. Gaia Early Data Release 3: The Galactic anticentre

Author: Gaia Collaboration, Antoja, T., McMillan, P., Kordopatis, G., Ramos, P., Helmi, A., Balbinot, E., Cantat-Gaudin, T., Chemin, L., Figueras, F., Jordi, C., Khanna, S., Romero-Gomez, M., Seabroke, G., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Babusiaux, C., Biermann, M., Creevey, O. L., Evans, D. W., Eyer, L., Hutton, A., Jansen, F., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Walton, N. A., Arenou, F., Bailer-Jones, C. A. L., Bastian, U., Cropper, M., Drimmel, R., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Castañeda, J., De Angeli, F., Ducourant, C., Fabricius, C., Fouesneau, M., Frémat, Y., Guerra, R., Guerrier, A., Guiraud, J., Piccolo, A. Jean-Antoine, Masana, E., Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Sordo, R., Tanga, P., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Andrae, R., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Brugaletta, E., Burgess, P. W., Busso, G., Carry, B., Cellino, A., Cheek, N., Clementini, G., Damerdji, Y., Davidson, M., Delchambre, L., Dell'Oro, A., Fernández-Hernández, J., Galluccio, L., García-Lario, P., Garcia-Reinaldos, M., González-Núñez, J., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hatzidimitriou, D., Heiter, U., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Lorca, A., Manteiga, M., Marchal, O., Marrese, P. M., Moitinho, A., Mora, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Richards, P. J., Riello, M., Rimoldini, L., Robin, A. C., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Ulla, A., Utrilla, E., van Leeuwen, M., van Reeven, W., Abbas, U., Aramburu, A. Abreu, Accart, S., Aerts, C., Aguado, Ajaj, M., Altavilla, G., Álvarez, M. A., Cid-Fuentes, J. Álvarez, Alves, J., Anderson, J. J. R. I., Varela, E. Anglada, Audard, M., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Baudesson-Stella, A., Becciani, U., Bellazzini, M., Bernet, M., Bertone, S., Bianchi, L., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Bucciarelli, B., Burlacu, A., Busonero, D., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cánovas, H., Carballo, R., Carlucci, T., Carnerero, M. I, Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Sampol, P. Castro, Chaoul, L., Charlot, P., Chiavassa, A., Cioni, M. -R. L., Comoretto, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, M., David, P., deLaverny, P., DeLuise, F., DeMarch, R., DeRidder, J., deSouza, R., de Teodoro, P., de Torres, A., del Peloso, E. F., del Pozo, E., Delgado, A., Delgado, H. E., Delisle, J. -B., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Eappachen, D., Enke, H., Esquej, P., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fienga, A., Fouron, C., Fragkoudi, F., Fraile, E., Franke, F., Gai, M., Garabato, D., Garcia-Gutierrez, A., García-Torres, M., Garofalo, A., Gavras, P., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomez, A., Gonzalez-Santamaria, I., González-Vidal, J. J., Granvik, M., Gutiérrez-Sánchez, R., Guy, L. P., Hauser, M., Haywood, M., Hidalgo, S. L., Hilger, T., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jasniewicz, G., Jonker, P. G., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Kochoska, A., Kontizas, M., Korn, A. J., Kostrzewa-Rutkowska, Z., Kruszyńska, K., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Fustec, Y. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Pardo, P. Madrero, Managau, S., Mann, R. G., Marchant, J. M., Marconi, M., Santos, M. M. S. Marcos, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Montegriffo, P., Mor, R., Morbidelli, R., Morel, T., Morris, D., Mulone, A. F., Munoz, D., Muraveva, T., Murphy, C. P., Musella, I., Noval, L., Ordénovic, C., Orrù, G., Osinde, J., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Panahi, A., Pawlak, M., Esteller, X. Peñalosa, Penttilä, A., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Poretti, E., Poujoulet, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Rambaux, N., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Reylé, C., Ripepi, V., Riva, A., Rixon, G., Robichon, N., Robin, C., Roelens, M., Rohrbasser, L., Rowell, N., Royer, F., Rybicki, K. A., Sadowski, G., Sellés, A. Sagristà, Sahlmann, J., Salgado, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Siddiqui, H. I., Siebert, A., Siltala, L., Slezak, E., Smart, R. L., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Szabados, L., Szegedi-Elek, E., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Thuillot, W., Tonello, N., Torra, F., Torra, J., Turon, C., Unger, N., Vaillant, M., van Dillen, E., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, L., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., Zurbach, C., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We aim to demonstrate the scientific potential of the Gaia Early Data Release 3 (EDR3) for the study of the Milky Way structure and evolution. We used astrometric positions, proper motions, parallaxes, and photometry from EDR3 to select different populations and components and to calculate the distances and velocities in the direction of the anticentre. We explore the disturbances of the current disc, the spatial and kinematical distributions of early accreted versus in-situ stars, the structures in the outer parts of the disc, and the orbits of open clusters Berkeley 29 and Saurer 1. We find that: i) the dynamics of the Galactic disc are very complex with vertical asymmetries, and new correlations, including a bimodality with disc stars with large angular momentum moving vertically upwards from below the plane, and disc stars with slightly lower angular momentum moving preferentially downwards; ii) we resolve the kinematic substructure (diagonal ridges) in the outer parts of the disc for the first time; iii) the red sequence that has been associated with the proto-Galactic disc that was present at the time of the merger with Gaia-Enceladus-Sausage is currently radially concentrated up to around 14 kpc, while the blue sequence that has been associated with debris of the satellite extends beyond that; iv) there are density structures in the outer disc, both above and below the plane, most probably related to Monoceros, the Anticentre Stream, and TriAnd, for which the Gaia data allow an exhaustive selection of candidate member stars and dynamical study; and v) the open clusters Berkeley~29 and Saurer~1, despite being located at large distances from the Galactic centre, are on nearly circular disc-like orbits. We demonstrate how, once again, the Gaia are crucial for our understanding of the different pieces of our Galaxy and their connection to its global structure and history., Comment: Gaia EDR3 performance verification paper, version 2 closer to published version in A&A, complete list of authors
Published: 2021
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20. Gaia Early Data Release 3: The Gaia Catalogue of Nearby Stars

Author: Gaia Collaboration, Smart, R. L., Sarro, L. M., Rybizki, J., Reylé, C., Robin, A. C., Hambly, N. C., Abbas, U., Barstow, M. A., de Bruijne, J. H. J., Bucciarelli, B., Carrasco, J. M., Cooper, W. J., Hodgkin, S. T., Masana, E., Michalik, D., Sahlmann, J., Sozzetti, A., Brown, A. G. A., Vallenari, A., Prusti, T., Babusiaux, C., Biermann, M., Creevey, O. L., Evans, D. W., Eyer, L., Hutton, A., Jansen, F., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Walton, N. A., Arenou, F., Bailer-Jones, C. A. L., Bastian, U., Cropper, M., Drimmel, R., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Castañeda, J., De Angeli, F., Ducourant, C., Fabricius, C., Fouesneau, M., Frémat, Y., Guerra, R., Guerrier, A., Guiraud, J., Piccolo, A. Jean-Antoine, Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Seabroke, G. M., Sordo, R., Tanga, P., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Andrae, R., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Brugaletta, E., Burgess, P. W., Busso, G., Carry, B., Cellino, A., Cheek, N., Clementini, G., Damerdji, Y., Davidson, M., Delchambre, L., Dell'Oro, A., Fernández-Hernández, J., Galluccio, L., García-Lario, P., Garcia-Reinaldos, M., González-Núñez, J., Gosset, E., Haigron, R., Halbwachs, J. -L., Harrison, D. L., Hatzidimitriou, D., Heiter, U., Hernández, J., Hestroffer, D., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Lorca, A., Manteiga, M., Marchal, O., Marrese, P. M., Moitinho, A., Mora, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Richards, P. J., Riello, M., Rimoldini, L., Roegiers, T., Siopis, C., Smith, M., Ulla, A., Utrilla, E., van Leeuwen, M., van Reeven, W., Aramburu, A. Abreu, Accart, S., Aerts, C., Aguado, J. J., Ajaj, M., Altavilla, G., Álvarez, M. A., Cid-Fuentes, J. Álvarez, Alves, J., Anderson, R. I., Varela, E. Anglada, Antoja, T., Audard, M., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Baudesson-Stella, A., Becciani, U., Bellazzini, M., Bernet, M., Bertone, S., Bianchi, L., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Burlacu, A., Busonero, D., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cánovas, H., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I, Casamiquela, L., Castellani, M., Castro-Ginard, A., Sampol, P. Castro, Chaoul, L., Charlot, P., Chemin, L., Chiavassa, A., Cioni, M. -R. L., Comoretto, G., Cornez, T., Cowell, S., Crifo, F., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, M., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Teodoro, P., de Torres, A., del Peloso, E. F., del Pozo, E., Delgado, A., Delgado, H. E., Delisle, J. -B., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Eappachen, D., Edvardsson, B., Enke, H., Esquej, P., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fienga, A., Figueras, F., Fouron, C., Fragkoudi, F., Fraile, E., Franke, F., Gai, M., Garabato, D., Garcia-Gutierrez, A., García-Torres, M., Garofalo, A., Gavras, P., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., Gonzalez-Santamaria, I., González-Vidal, J. J., Granvik, M., Gutiérrez-Sánchez, R., Guy, L. P., Hauser, M., Haywood, M., Helmi, A., Hidalgo, S. L., Hilger, T., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jasniewicz, G., Jonker, P. G., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kochoska, A., Kontizas, M., Kordopatis, G., Korn, A. J., Kostrzewa-Rutkowska, Z., Kruszyńska, K., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Fustec, Y. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Pardo, P. Madrero, Managau, S., Mann, R. G., Marchant, J. M., Marconi, M., Santos, M. M. S. Marcos, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Messina, S., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Montegriffo, P., Mor, R., Morbidelli, R., Morel, T., Morris, D., Mulone, A. F., Munoz, D., Muraveva, T., Murphy, C. P., Musella, I., Noval, L., Ordénovic, C., Orrù, G., Osinde, J., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Panahi, A., Pawlak, M., Esteller, X. Peñalosa, Penttilä, A., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Poretti, E., Poujoulet, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Rambaux, N., Ramos, P., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Ripepi, V., Riva, A., Rixon, G., Robichon, N., Robin, C., Roelens, M., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Rybicki, K. A., Sadowski, G., Sellés, A. Sagristà, Salgado, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Slezak, E., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Szabados, L., Szegedi-Elek, E., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Thuillot, W., Tonello, N., Torra, F., Torra, J., Turon, C., Unger, N., Vaillant, M., van Dillen, E., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, L., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., Zurbach, C., and Zwitter, T.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We produce a clean and well-characterised catalogue of objects within 100\,pc of the Sun from the \G\ Early Data Release 3. We characterise the catalogue through comparisons to the full data release, external catalogues, and simulations. We carry out a first analysis of the science that is possible with this sample to demonstrate its potential and best practices for its use. The selection of objects within 100\,pc from the full catalogue used selected training sets, machine-learning procedures, astrometric quantities, and solution quality indicators to determine a probability that the astrometric solution is reliable. The training set construction exploited the astrometric data, quality flags, and external photometry. For all candidates we calculated distance posterior probability densities using Bayesian procedures and mock catalogues to define priors. Any object with reliable astrometry and a non-zero probability of being within 100\,pc is included in the catalogue. We have produced a catalogue of \NFINAL\ objects that we estimate contains at least 92\% of stars of stellar type M9 within 100\,pc of the Sun. We estimate that 9\% of the stars in this catalogue probably lie outside 100\,pc, but when the distance probability function is used, a correct treatment of this contamination is possible. We produced luminosity functions with a high signal-to-noise ratio for the main-sequence stars, giants, and white dwarfs. We examined in detail the Hyades cluster, the white dwarf population, and wide-binary systems and produced candidate lists for all three samples. We detected local manifestations of several streams, superclusters, and halo objects, in which we identified 12 members of \G\ Enceladus. We present the first direct parallaxes of five objects in multiple systems within 10\,pc of the Sun., Comment: 45 Pages, 39 figures in main part and 18 in appendix, tables on CDS
Published: 2020
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21. Gaia Early Data Release 3: Acceleration of the solar system from Gaia astrometry

Author: Gaia Collaboration, Klioner, S. A., Mignard, F., Lindegren, L., Bastian, U., McMillan, P. J., Hernández, J., Hobbs, D., Ramos-Lerate, M., Biermann, M., Bombrun, A., de Torres, A., Gerlach, E., Geyer, R., Hilger, T., Lammers, U., Steidelmüller, H., Stephenson, C. A., Brown, A. G. A., Vallenari, A., Prusti, T., de Bruijne, J. H. J., Babusiaux, C., Creevey, O. L., Evans, D. W., Eyer, L., Hutton, A., Jansen, F., Jordi, C., Luri, X., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Walton, N. A., Arenou, F., Bailer-Jones, C. A. L., Cropper, M., Drimmel, R., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Castañeda, J., De Angeli, F., Ducourant, C., Fabricius, C., Fouesneau, M., Frémat, Y., Guerra, R., Guerrier, A., Guiraud, J., Piccolo, A. Jean-Antoine, Masana, E., Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Seabroke, G. M., Sordo, R., Tanga, P., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Andrae, R., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Brugaletta, E., Burgess, P. W., Busso, G., Carry, B., Cellino, A., Cheek, N., Clementini, G., Damerdji, Y., Davidson, M., Delchambre, L., Dell'Oro, A., Fernández-Hernández, J., Galluccio, L., García-Lario, P., Garcia-Reinaldos, M., González-Núñez, J., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hatzidimitriou, D., Heiter, U., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Lorca, A., Manteiga, M., Marchal, O., Marrese, P. M., Moitinho, A., Mora, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Richards, P. J., Riello, M., Rimoldini, L., Robin, A. C., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Ulla, A., Utrilla, E., van Leeuwen, M., van Reeven, W., Abbas, U., Aramburu, A. Abreu, Accart, S., Aerts, C., Aguado, J. J., Ajaj, M., Altavilla, G., Álvarez, M. A., Cid-Fuentes, J. Álvarez, Alves, J., Anderson, R. I., Varela, E. Anglada, Antoja, T., Audard, M., Baines, D., Baker, S. G., Balaguer-Nú\-nez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Baudesson-Stella, A., Becciani, U., Bellazzini, M., Bernet, M., Bertone, S., Bianchi, L., Blanco-Cuaresma, S., Boch, T., Bossini, D., Bouquillon, S., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Bucciarelli, B., Burlacu, A., Busonero, D., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cánovas, H., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I, Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Sampol, P. Castro, Chaoul, L., Charlot, P., Chemin, L., Chiavassa, A., Comoretto, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, M., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Teodoro, P., del Peloso, E. F., del Pozo, E., Delgado, A., Delgado, H. E., Delisle, J. -B., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Eappachen, D., Enke, H., Esquej, P., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fienga, A., Figueras, F., Fouron, C., Fragkoudi, F., Fraile, E., Franke, F., Gai, M., Garabato, D., Garcia-Gutierrez, A., García-Torres, M., Garofalo, A., Gavras, P., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomez, A., Gonzalez-Santamaria, I., González-Vidal, J. J., Granvik, M., Gutiérrez-Sánchez, R., Guy, L. P., Hauser, M., Haywood, M., Helmi, A., Hidalgo, S. L., Hładczuk, N., Holland, G., Huckle, H. E., Jasniewicz, G., Jonker, P. G., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kochoska, A., Kordopatis, G., Korn, A. J., Kostrzewa-Rutkowska, Z., Kruszyńska, K., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Fustec, Y. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Pardo, P. Madrero, Managau, S., Mann, R. G., Marchant, J. M., Marconi, M., Santos, M. M. S. Marcos, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Montegriffo, P., Mor, R., Morbidelli, R., Morel, T., Morris, D., Mulone, A. F., Munoz, D., Muraveva, T., Murphy, C. P., Musella, I., Noval, L., Ordénovic, C., Orrù, G., Osinde, J., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Panahi, A., Pawlak, M., Esteller, X. Pe\-nalosa, Penttilä, A., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Poretti, E., Poujoulet, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Rambaux, N., Ramos, P., Fiorentin, P. Re, Regibo, S., Reylé, C., Ripepi, V., Riva, A., Rixon, G., Robichon, N., Robin, C., Roelens, M., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Rybicki, K. A., Sadowski, G., Sellés, A. Sagristà, Sahlmann, J., Salgado, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Siddiqui, H. I., Siebert, A., Siltala, L., Slezak, E., Smart, R. L., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spoto, F., Steele, I. A., Süveges, M., Szabados, L., Szegedi-Elek, E., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Thuillot, W., Tonello, N., Torra, F., Torray, J., Turon, C., Unger, N., Vaillant, M., van Dillen, E., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., Zurbach, C., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions. Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar system barycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution. Methods. The effect of the acceleration is obtained as a part of the general expansion of the vector field of proper motions in Vector Spherical Harmonics (VSH). Various versions of the VSH fit and various subsets of the sources are tried and compared to get the most consistent result and a realistic estimate of its uncertainty. Additional tests with the Gaia astrometric solution are used to get a better idea on possible systematic errors in the estimate. Results. Our best estimate of the acceleration based on Gaia EDR3 is $(2.32 \pm 0.16) \times 10^{-10}$ m s${}^{-2}$ (or $7.33 \pm 0.51$ km s$^{-1}$ Myr${}^{-1}$) towards $\alpha = 269.1^\circ \pm 5.4^\circ$, $\delta = -31.6^\circ \pm 4.1^\circ$, corresponding to a proper motion amplitude of $5.05 \pm 0.35$ $\mu$as yr${}^{-1}$. This is in good agreement with the acceleration expected from current models of the Galactic gravitational potential. We expect that future Gaia data releases will provide estimates of the acceleration with uncertainties substantially below 0.1 $\mu$as yr${}^{-1}$., Comment: A&A, accepted
Published: 2020
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22. Gaia Early Data Release 3: Structure and properties of the Magellanic Clouds

Author: Gaia Collaboration, Luri, X., Chemin, L., Clementini, G., Delgado, H. E., McMillan, P. J., Romero-Gómez, M., Balbinot, E., Castro-Ginard, A., Mor, R., Ripepi, V., Sarro, L. M., Cioni, M. -R. L., Fabricius, C., Garofalo, A., Helmi, A., Muraveva, T., Brown, A. G. A., Vallenari, A., Prusti, T., de, J. H. J., Babusiaux, C., Biermann, M., Creevey, O. L., Evans, D. W., Eyer, L., Hutton, A., Jansen, F., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Walton, N. A., Arenou, F., Bailer-Jones, C. A. L., Bastian, U., Cropper, M., Drimmel, R., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Castañeda, J., De, F., Ducourant, C., Fouesneau, M., Frémat, Y., Guerra, R., Guerrier, A., Guiraud, J., Jean-Antoine, A., Masana, E., Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Seabroke, G. M., Sordo, R., Tanga, P., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Andrae, R., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Brugaletta, E., Burgess, P. W., Busso, G., Carry, B., Cellino, A., Cheek, N., Damerdji, Y., Davidson, M., Delchambre, L., Dell'Oro, A., Fernández-Hernández, J., Galluccio, L., García-Lario, P., Garcia-Reinaldos, M., González-Núñez, J., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hatzidimitriou, D., Heiter, U., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., Löffler, W., Lorca, A., Manteiga, M., Marchal, O., Marrese, P. M., Moitinho, A., Mora, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Recio-Blanco, A., Richards, P. J., Riello, M., Rimoldini, L., Robin, A. C., Roegiers, T., Rybizki, J., Siopis, C., Smith, M., Sozzetti, A., Ulla, A., Utrilla, E., van Leeuwen, M., van Reeven, W., Abbas, U., Abreu, A., Accart, S., Aerts, C., Aguado, J. J., Ajaj, M., Altavilla, G., Álvarez, M. A., Cid-Fuentes, J. Álvarez, Alves, J., Anderson, R. I., Varela, E. Anglada, Antoja, T., Audard, M., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Baudesson-Stella, A., Becciani, U., Bellazzini, M., Bernet, M., Bertone, S., Bianchi, L., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Bucciarelli, B., Burlacu, A., Busonero, D., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cánovas, H., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I, Carrasco, J. M., Casamiquela, L., Castellani, M., Sampol, P. Castro, Chaoul, L., Charlot, P., Chiavassa, A., Comoretto, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, M., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Teodoro, P., de Torres, A., del Peloso, E. F., del Pozo, E., Delgado, A., Delisle, J. -B., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Eappachen, D., Enke, H., Esquej, P., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fienga, A., Figueras, F., Fouron, C., Fragkoudi, F., Fraile, E., Franke, F., Gai, M., Garabato, D., Garcia-Gutierrez, A., García-Torres, M., Gavras, P., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomez, A., Gonzalez-Santamaria, I., González-Vidal, J. J., Granvik, M., Gutiérrez-Sánchez, R., Guy, L. P., Hauser, M., Haywood, M., Hidalgo, S. L., Hilger, T., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jasniewicz, G., Jonker, P. G., Juaristi, J., Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kochoska, A., Kontizas, M., Kordopatis, G., Korn, A. J., Kostrzewa-Rutkowska, Z., Kruszyńska, K., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Fustec, Y. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Madrero, P., Managau, S., Mann, R. G., Marchant, J. M., Marconi, M., Marcos, M. M. S., Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Montegriffo, P., Morbidelli, R., Morel, T., Morris, D., Mulone, A. F., Munoz, D., Murphy, C. P., Musella, I., Noval, L., Ordénovic, C., Orrù, G., Osinde, J., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Panahi, A., Pawlak, M., Peñalosa, X., Penttilä, A., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Poretti, E., Poujoulet, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Rambaux, N., Ramos, P., Ramos-Lerate, M., Re, P., Regibo, S., Reylé, C., Riva, A., Rixon, G., Robichon, N., Robin, C., Roelens, M., Rohrbasser, L., Rowell, N., Royer, F., Rybicki, K. A., Sadowski, G., Sagristà, A., Sahlmann, J., Salgado, J., Salguero, E., Samaras, N., Sanchez, V., Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Siddiqui, H. I., Siebert, A., Siltala, L., Slezak, E., Smart, R. L., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spoto, F., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Süveges, M., Szabados, L., Szegedi-Elek, E., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Thuillot, W., Tonello, N., Torra, F., Torra, J., Turon, C., Unger, N., Vaillant, M., van, E., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., Zurbach, C., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We compare the Gaia DR2 and Gaia EDR3 performances in the study of the Magellanic Clouds and show the clear improvements in precision and accuracy in the new release. We also show that the systematics still present in the data make the determination of the 3D geometry of the LMC a difficult endeavour; this is at the very limit of the usefulness of the Gaia EDR3 astrometry, but it may become feasible with the use of additional external data. We derive radial and tangential velocity maps and global profiles for the LMC for the several subsamples we defined. To our knowledge, this is the first time that the two planar components of the ordered and random motions are derived for multiple stellar evolutionary phases in a galactic disc outside the Milky Way, showing the differences between younger and older phases. We also analyse the spatial structure and motions in the central region, the bar, and the disc, providing new insights into features and kinematics. Finally, we show that the Gaia EDR3 data allows clearly resolving the Magellanic Bridge, and we trace the density and velocity flow of the stars from the SMC towards the LMC not only globally, but also separately for young and evolved populations. This allows us to confirm an evolved population in the Bridge that is slightly shift from the younger population. Additionally, we were able to study the outskirts of both Magellanic Clouds, in which we detected some well-known features and indications of new ones., Comment: This paper is part of the "demonstration papers" released with Gaia EDR3: https://www.cosmos.esa.int/web/gaia/earlydr3
Published: 2020
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23. Gaia Early Data Release 3: Summary of the contents and survey properties

Author: Gaia Collaboration, Brown, A. G. A, Vallenari, A., Prusti, T., de Bruijne, J. H. J., Babusiaux, C., Biermann, M., Creevey, O. L., Evans, D. W., Eyer, L., Hutton, A., Jansen, F., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Soubiran, C., Walton, N. A., Arenou, F., Bailer-Jones, C. A. L., Bastian, U., Cropper, M., Drimmel, R., Katz, D., Lattanzi, M. G., van Leeuwen, F., Bakker, J., Cacciari, C., Castañeda, J., De Angeli, F., Ducourant, C., Fabricius, C., Fouesneau, M., Frémat, Y., Guerra, R., Guerrier, A., Guiraud, J., Piccolo, A. Jean-Antoine, Masana, E., Messineo, R., Mowlavi, N., Nicolas, C., Nienartowicz, K., Pailler, F., Panuzzo, P., Riclet, F., Roux, W., Seabroke, G. M., Sordo, R., Tanga, P., Thévenin, F., Gracia-Abril, G., Portell, J., Teyssier, D., Altmann, M., Andrae, R., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Brugaletta, E., Burgess, P. W., Busso, G., Carry, B., Cellino, A., Cheek, N., Clementini, G., Damerdji, Y., Davidson, M., Delchambre, L., Dell'Oro, A., Fernández-Hernández, J., Galluccio, L., García-Lario, P., Garcia-Reinaldos, M., González-Núñez, J., Gosset, E., Haigron, R., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hatzidimitriou, D., Heiter, U., Hernández, J., Hestroffer, D., Hodgkin, S. T., Holl, B., Janßen, K., de Fombelle, G. Jevardat, Jordan, S., Krone-Martins, A., Lanzafame, A. C., o}ffler, W. L\"{, Lorca, A., Manteiga, M., Marchal, O., Marrese, P. M., Moitinho, A., Mora, A., Muinonen, K., Osborne, P., Pancino, E., Pauwels, T., Petit, J. -M., Recio-Blanco, A., Richards, P. J., Riello, M., Rimoldini, L., Robin, A. C., Roegiers, T., Rybizki, J., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Ulla, A., Utrilla, E., van Leeuwen, M., van Reeven, W., Abbas, U., Aramburu, A. Abreu, Accart, S., Aerts, C., Aguado, J. J., Ajaj, M., Altavilla, G., Álvarez, M. A., Cid-Fuentes, J. Álvarez, Alves, J., Anderson, R. I., Varela, E. Anglada, Antoja, T., Audard, M., Baines, D., Baker, S. G., Balaguer-Núñez, L., Balbinot, E., Balog, Z., Barache, C., Barbato, D., Barros, M., Barstow, M. A., Bartolomé, S., Bassilana, J. -L., Bauchet, N., Baudesson-Stella, A., Becciani, U., Bellazzini, M., Bernet, M., Bertone, S., Bianchi, L., Blanco-Cuaresma, S., Boch, T., Bombrun, A., Bossini, D., Bouquillon, S., Bragaglia, A., Bramante, L., Breedt, E., Bressan, A., Brouillet, N., Bucciarelli, B., Burlacu, A., Busonero, D., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cánovas, H., Cantat-Gaudin, T., Carballo, R., Carlucci, T., Carnerero, M. I, Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Sampol, P. Castro, Chaoul, L., Charlot, P., Chemin, L., Chiavassa, A., Cioni, M. -R. L., Comoretto, G., Cooper, W. J., Cornez, T., Cowell, S., Crifo, F., Crosta, M., Crowley, C., Dafonte, C., Dapergolas, A., David, M., David, P., de Laverny, P., De Luise, F., De March, R., De Ridder, J., de Souza, R., de Teodoro, P., de Torres, A., del Peloso, E. F., del Pozo, E., Delbo, M., Delgado, A., Delgado, H. E., Delisle, J. -B., Di Matteo, P., Diakite, S., Diener, C., Distefano, E., Dolding, C., Eappachen, D., Edvardsson, B., Enke, H., Esquej, P., Fabre, C., Fabrizio, M., Faigler, S., Fedorets, G., Fernique, P., Fienga, A., Figueras, F., Fouron, C., Fragkoudi, F., Fraile, E., Franke, F., Gai, M., Garabato, D., Garcia-Gutierrez, A., García-Torres, M., Garofalo, A., Gavras, P., Gerlach, E., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Gomel, R., Gomez, A., Gonzalez-Santamaria, I., González-Vidal, J. J., Granvik, M., Gutiérrez-Sánchez, R., Guy, L. P., Hauser, M., Haywood, M., Helmi, A., Hidalgo, S. L., Hilger, T., Hładczuk, N., Hobbs, D., Holland, G., Huckle, H. E., Jasniewicz, G., Jonker, P. G., Campillo, J. Juaristi, Julbe, F., Karbevska, L., Kervella, P., Khanna, S., Kochoska, A., Kontizas, M., Kordopatis, G., Korn, A. J., Kostrzewa-Rutkowska, Z., Kruszyńska, K., Lambert, S., Lanza, A. F., Lasne, Y., Campion, J. -F. Le, Fustec, Y. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Liao, S., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Pardo, P. Madrero, Managau, S., Mann, R. G., Marchant, J. M., Marconi, M., Santos, M. M. S. Marcos, Marinoni, S., Marocco, F., Marshall, D. J., Polo, L. Martin, Martín-Fleitas, J. M., Masip, A., Massari, D., Mastrobuono-Battisti, A., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Mints, A., Molina, D., Molinaro, R., Molnár, L., Montegriffo, P., Mor, R., Morbidelli, R., Morel, T., Morris, D., Mulone, A. F., Munoz, D., Muraveva, T., Murphy, C. P., Musella, I., Noval, L., Ordénovic, C., Orrù, G., Osinde, J., Pagani, C., Pagano, I., Palaversa, L., Palicio, P. A., Panahi, A., Pawlak, M., Esteller, X. Peñalosa, a}, A. Penttil\"{, Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Poretti, E., Poujoulet, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rainer, M., Raiteri, C. M., Rambaux, N., Ramos, P., Ramos-Lerate, M., Fiorentin, P. Re, Regibo, S., Reylé, C., Ripepi, V., Riva, A., Rixon, G., Robichon, N., Robin, C., Roelens, M., Rohrbasser, L., Romero-Gómez, M., Rowell, N., Royer, F., Rybicki, K. A., Sadowski, G., Sellés, A. Sagristà, Sahlmann, J., Salgado, J., Salguero, E., Samaras, N., Gimenez, V. Sanchez, Sanna, N., Santoveña, R., Sarasso, M., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Semeux, D., Shahaf, S., Siddiqui, H. I., Siebert, A., Siltala, L., Slezak, E., Smart, R. L., Solano, E., Solitro, F., Souami, D., Souchay, J., Spagna, A., Spoto, F., Steele, I. A., u}ller, H. Steidelm\"{, Stephenson, C. A., u}veges, M. S\"{, Szabados, L., Szegedi-Elek, E., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Thuillot, W., Tonello, N., Torra, F., Torra, J., Turon, C., Unger, N., Vaillant, M., van Dillen, E., Vanel, O., Vecchiato, A., Viala, Y., Vicente, D., Voutsinas, S., Weiler, M., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Yvard, P., Zhao, H., Zorec, J., Zucker, S., Zurbach, C., and Zwitter, T.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the early installment of the third Gaia data release, Gaia EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from Gaia DR2. Gaia EDR3 contains celestial positions and the apparent brightness in G for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (G_BP-G_RP) colour are also available. The passbands for G, G_BP, and G_RP are provided as part of the release. For ease of use, the 7 million radial velocities from Gaia DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of Gaia DR3. Finally, Gaia EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the Gaia-CRF3, which is based solely on extragalactic sources. The creation of the source list for Gaia EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for Gaia DR2, but it does feature new sources and there are some notable changes. The source list will not change for Gaia DR3. Gaia EDR3 represents a significant advance over Gaia DR2, with parallax precisions increased by 30 percent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30--40 percent for the parallaxes and by a factor ~2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for G, G_BP, and G_RP is valid over the entire magnitude and colour range, with no systematics above the 1 percent level., Comment: Accepted for A&A Special Issue on Gaia EDR3, 21 pages, 2 figures. This version includes the updates in the erratum (https://doi.org/10.1051/0004-6361/202039657e)
Published: 2020
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24. MOONS Surveys of the Milky Way and its Satellites

Author: Gonzalez, O. A., Mucciarelli, A., Origlia, L., Schultheis, M., Caffau, E., Di Matteo, P., Randich, S., Recio-Blanco, A., Zoccali, M., Bonifacio, P., Dalessandro, E., Schiavon, R. P., Pancino, E., Taylor, W., Valenti, E., Rojas-Arriagada, A., Sacco, G., Biazzo, K., Bellazzini, M., Cioni, M. -R. L., Clementini, G., Ramos, R. Contreras, de Laverny, P., Evans, C., Haywood, M., Hill, V., Ibata, R., Lucatello, S., Magrini, L., Martin, N., Nisini, B., Sanna, N., Cirasuolo, M., Maiolino, R., Afonso, J., Lilly, S., Flores, H., Oliva, E., Paltani, S., and Vanzi, L.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The study of resolved stellar populations in the Milky Way and other Local Group galaxies can provide us with a fossil record of their chemo-dynamical and star-formation histories over timescales of many billions of years. In the galactic components and stellar systems of the Milky Way and its satellites, individual stars can be resolved. Therefore, they represent a unique laboratory in which to investigate the details of the processes behind the formation and evolution of the disc and dwarf/irregular galaxies. MOONS at the VLT represents a unique combination of an efficient infrared multi-object spectrograph and a large-aperture 8-m-class telescope which will sample the cool stellar populations of the dense central regions of the Milky Way and its satellites, delivering accurate radial velocities, metallicities, and other chemical abundances for several millions of stars over its lifetime (see Cirasuolo et al., this issue). MOONS will observe up to 1000 targets across a 25-arcminute field of view in the optical and near-infrared (0.6-1.8 micron) simultaneously. A high-resolution (R~19700) setting in the H band has been designed for the accurate determination of stellar abundances such as alpha, light, iron-peak and neutron-capture elements., Comment: 6 pages, 2 figures, Published on the ESO Messenger No. 180
Published: 2020
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25. Escapees from the bar resonances. On the presence of low-eccentricity, metal-rich stars at the Solar vicinity

Author: Khoperskov, S., Di Matteo, P., Haywood, M., Gomez, A., and Snaith, O. N.
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: Understanding radial migration is a crucial point to build relevant chemical and dynamical evolution models of the Milky Way disk. In this paper, we analyze a high-resolution N-body simulation of a Milky Way-type galaxy to study the role that the slowing down of a stellar bar has is generating migration from the inner to the outer disk. Stellar particles are trapped by the main resonances (corotation and Outer Lindblad resonance) which then propagate outwards across the disk due to the bar slowing down. Once the bar strength reaches its maximal amplitude, some of the stars, delivered to the outer disk, escape the resonances and some of them settle on nearly circular orbits. The number of the escaped stars gradually increases also due to the decrease of the bar strength when the boxy/peanut bulge forms. We show that this mechanism is not limited only to stars on nearly circular orbits: also stars initially on more eccentric orbits can be transferred outwards (out to the OLR location) and can end up on nearly circular orbits. Therefore, the propagation of the bar resonances outwards can induce the circularization of the orbits of some of the migrating stars. The mechanism investigated in this paper can explain the presence of metal-rich stars at the solar vicinity and more generally in the outer galactic disk. Our dynamical model predicts that up to 3% of stars in between of corotation and the OLR can be formed in the innermost region of the Milky Way. The epoch of the Milky Way bar formation can be potentially constrained by analyzing the age distribution of the most metal-rich stars at the solar vicinity., Comment: 9 pages, 8 figures, A&A in press
Published: 2019
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26. Reviving old controversies: is the early Galaxy flat or round? Investigations into the early phases of the Milky Way formation through stellar kinematics and chemical abundances

Author: Di Matteo, P., Spite, M., Haywood, M., Bonifacio, P., Gómez, A., Spite, F., and Caffau, E.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We analyse a set of very metal-poor stars for which accurate chemical abundances have been obtained as part of the ESO Large Program "First stars" in the light of the Gaia DR2 data. The kinematics and orbital properties of the stars in the sample show they probably belong to the thick disc, partially heated to halo kinematics, and to the accreted Nissen & Schuster-Gaia Sausage-Enceladus satellite. The continuity of these properties with stars at both higher ($\rm [Fe/H]>-2$) and lower metallicities ($\rm [Fe/H]<-4.$) suggests that the Galaxy at $\rm [Fe/H] \lesssim -0.5$ and down to at least $\rm [Fe/H]\sim-6$ is dominated by these two populations. In particular, we show that the disc extends continuously from $\rm [Fe/H] \le -4$ (where stars with disc-like kinematics have been recently discovered) up to $\rm [Fe/H] \ge -2$, the metallicity regime of the Galactic thick disc. There exists indeed an "ultra-metal poor thick disc", which constitutes the extremely metal-poor tail of the canonical Galactic thick disc, and which extends this latter from $\rm [Fe/H] \sim -0.5$ up to the most metal-poor stars discovered in the Galaxy up to date. These results suggest that the disc may be the main, and possibly the only stellar population that has formed in the Galaxy at these metallicities. This requires that the dissipative collapse that led to the formation of the old Galactic disc must have been extremely fast. We also discuss these results in the light of recent simulation efforts made to reproduce the first stages of Milky Way-type galaxies., Comment: 30 pages, 18 figures, A&A, in press
Published: 2019
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27. Hic sunt dracones: Cartography of the Milky Way spiral arms and bar resonances with Gaia Data Release 2

Author: Khoperskov, S., Gerhard, O., Di Matteo, P., Haywood, M., Katz, D., Khrapov, S., Khoperskov, A., and Arnaboldi, M.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: In this paper we introduce a new method for analysing Milky Way phase-space which allows us to reveal the imprint left by the Milky Way bar and spiral arms on the stars with full phase-space data in Gaia Data Release 2. The unprecedented quality and extended spatial coverage of these data enable us to discover six prominent stellar density structures in the disc to a distance of 5 kpc from the Sun. Four of these structures correspond to the spiral arms detected previously in the gas and young stars (Scutum-Centaurus, Sagittarius, Local and Perseus). The remaining two are associated with the main resonances of the Milky Way bar where corotation is placed at around 6.2 kpc and the outer Lindblad resonance beyond the Solar radius, at around 9 kpc. For the first time we provide evidence of the imprint left by spiral arms and resonances in the stellar densities not relying on a specific tracer, through enhancing the signatures left by these asymmetries. Our method offers new avenues for studying how the stellar populations in our Galaxy are shaped., Comment: 10 pages, 6 figures, accepted for publication in A&A Letters
Published: 2019
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28. Revisiting long-standing puzzles of the Milky Way: the Sun and its vicinity as typical outer disk chemical evolution

Author: Haywood, M., Snaith, O. N., Lehnert, M. D., Di Matteo, P., and Khoperskov, S.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present a scenario of the chemical enrichment of the solar neighborhood that solves the G-dwarf problem by taking into account constraints on a larger scale. We argue that the Milky Way disk within 10 kpc has been enriched to solar metallicity by a massive stellar population: the thick disk, which itself formed from a massive turbulent gaseous disk. The key new consideration is that the pre-enrichment provided by the thick disk is not related to the mass fraction of this stellar population at the solar radius, as is classically assumed in inside-out scenarios, but is actually related to the formation of the entire massive thick disk, due to the vigorous gas phase mixing that occurred during its formation. Hence, the fact that this population represents only 15-25% of the local stellar surface density today is irrelevant for `solving' the G-dwarf problem. The only condition for this scenario to work is that the thick disk was formed from a turbulent gaseous disk that permitted a homogeneous -- not radially dependent -- distribution of metals, allowing the solar ring to be enriched to solar metallicity. At the solar radius, the gas flowing from the outer disk combined with the solar metallicity gas left over from thick disk formation, providing the fuel necessary to form the thin disk at the correct metallicity to solve the G-dwarf problem. Chemical evolution at R$>$6 kpc, and in particular beyond the solar radius, can be reproduced with the same scheme. These results imply that the local metallicity distribution is not connected to the gas accretion history of the Milky Way. Finally, we argue that the Sun is the result of the evolution typical of stars in the disk beyond $\sim$6 kpc (i.e., also undergoing dilution), and has none of the characteristics of inner disk stars. [Abridged], Comment: 15 pages, 7 figures. Accepted for publication in A&A, published version
Published: 2019
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29. On the ridges, undulations & streams in Gaia DR2: Linking the topography of phase-space to the orbital structure of an N-body bar

Author: Fragkoudi, F., Katz, D., Trick, W., White, S. D. M., Di Matteo, P., Sormani, M. C., Khoperskov, S., Haywood, M., Hallé, A., and Gómez, A.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We explore the origin of phase-space substructures revealed by the second Gaia data release in the disc of the Milky Way, such as the ridges in the $V_{\phi}$-$r$ plane, the undulations in the $V_{\phi}$-$r$-$V_r$ space and the streams in the $V_{\phi}$-$V_r$ plane. We use a collisionless N-body simulation with co-spatial thin and thick discs, along with orbit integration, to study the orbital structure close to the Outer Lindblad Resonance (OLR) of the bar. We find that a prominent, long-lived ridge is formed in the $V_{\phi}$-$r$ plane due to the OLR which translates to streams in the $V_{\phi}$-$V_r$ plane and examine which closed periodic and trapped librating orbits are responsible for these features. We find that orbits which carry out small librations around the $x_1(1)$ family are preferentially found at negative $V_r$, giving rise to a `horn'-like feature, while orbits with larger libration amplitudes, trapped around the $x_1(2)$ and $x_1(1)$ families, constitute the positive $V_r$ substructure, i.e. the Hercules-like feature. This changing libration amplitude of orbits will translate to a changing ratio of thin/thick disc stars, which could have implications on the metallicity distribution in this plane. We find that a scenario in which the Sun is placed close to the OLR gives rise to a strong asymmetry in $V_r$ in the $V_{\phi}$-$V_r$ plane (i.e. Hercules vs. `the horn') and subsequently to undulations in the $V_{\phi}$-$r$-$V_r$ space. We also explore a scenario in which the Sun is placed closer to the bar corotation and find that the bar perturbation $alone$ cannot give rise to the these features., Comment: 17 pages, accepted for publication in MNRAS
Published: 2019
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30. The disc origin of the Milky Way bulge: On the necessity of the thick disc

Author: Di Matteo, P., Fragkoudi, F., Khoperskov, S., Ciambur, B., Haywood, M., Combes, F., and Gómez, A.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: In the MW bulge, metal-rich stars form a strong bar and are more peanut-shaped than metal-poor stars. It has been recently claimed that this behavior is driven by the initial in-plane radial velocity dispersion of these populations, rather than by their initial vertical random motions. This has led to the suggestion that a thick disc is not necessary to explain the characteristics of the MW bulge. We rediscuss this issue by analyzing two dissipationless N-body simulations of boxy/peanut (b/p)-shaped bulges formed from composite stellar discs, made of kinematically cold and hot stellar populations, and we conclude that initial vertical random motions are as important as in-plane random motions in determining the relative contribution of cold and hot disc populations with height above the plane, the metallicity and age trends. Previous statements emphasizing the dominant role of in-plane motions in determining these trends are not confirmed. However, differences exist in the morphology and strength of the resulting b/p-shaped bulges: a model where disc populations have initially only different in-plane random motions, but similar thickness, results into a b/p bulge where all populations have a similar peanut shape, independently on their initial kinematics, or metallicity. We discuss the reasons behind these differences, and also predict the signatures that these two extreme initial conditions would leave on the vertical age and metallicity gradients of disc stars, outside the bulge region. We conclude that a metal-poor, kinematically (radial and vertical) hot component, that is a thick disc, is necessary in the MW before bar formation, supporting the scenario traced in previous works. [abridged], Comment: 17 pages, 16 figures, A&A, in press
Published: 2019
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31. The Milky Way has no in-situ halo other than the heated thick disc. Composition of the stellar halo and age-dating the last significant merger with Gaia DR2 and APOGEE

Author: Di Matteo, P., Haywood, M., Lehnert, M. D., Katz, D., Khoperskov, S., Snaith, O. N., Gómez, A., and Robichon, N.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Previous studies based on the analysis of Gaia DR2 data have revealed that accreted stars, possibly originating from a single progenitor satellite, are a significant component of the halo of our Galaxy, potentially constituting most of the halo stars at $\rm [Fe/H] < -1$ within a few kpc from the Sun and beyond. In this paper, we couple astrometric data from Gaia DR2 with elemental abundances from APOGEE DR14 to characterize the kinematics and chemistry of in-situ and accreted populations up to $\rm [Fe/H] \sim -2$. Accreted stars appear to significantly impact the Galactic chemo-kinematic relations, not only at $\rm [Fe/H] < -1$, but also at metallicities typical of the thick and metal-poor thin discs. They constitute about 60% of all stars at $\rm [Fe/H] < -1$, the remaining 40% being made of (metal-weak) thick disc stars. We find that the stellar kinematic fossil record shows the imprint left by this accretion event which heated the old Galactic disc. We are able to age-date this kinematic imprint, showing that the accretion occurred between 9 and 11 Gyr ago, and that it led to the last significant heating of the Galactic disc. An important fraction of stars with abundances typical of the (metal-rich) thick disc, and heated by this interaction, is now found in the Galactic halo. Indeed about half of the kinematically defined halo at few kpc from the Sun is composed of metal-rich thick disc stars. Moreover, we suggest that this metal-rich thick disc component dominates the stellar halo of the inner Galaxy. The new picture that emerges from this study is one where the standard non-rotating in-situ halo population, the collapsed halo, seems to be more elusive than ever., Comment: 25 pages, 24 figures, accepted for publication on A&A
Published: 2018
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32. Gaia Data Release 2: Observational Hertzsprung-Russell diagrams

Author: Gaia Collaboration, Babusiaux, C., van Leeuwen, F., Barstow, M. A., Jordi, C., Vallenari, A., Bossini, D., Bressan, A., Cantat-Gaudin, T., van Leeuwen, M., Brown, A. G. A., Prusti, T., de Bruijne, J. H. J., Bailer-Jones, C. A. L., Biermann, M., Evans, D. W., Eyer, L., Jansen, F., Klioner, S. A., Lammers, U., Lindegren, L., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Siddiqui, H. I., Soubiran, C., Walton, N. A., Arenou, F., Bastian, U., Cropper, M., Drimmel, R., Katz, D., Lattanzi, M. G., Bakker, J., Cacciari, C., Castañeda, J., Chaoul, L., Cheek, N., DeAngeli, F., Fabricius, C., Guerra, R., Holl, B., Masana, E., Messineo, R., Mowlavi, N., Nienartowicz, K., Panuzzo, P., Portell, J., Riello, M., Seabroke, G. M., Tanga, P., Thévenin, F., Gracia-Abril, G., Comoretto, G., Garcia-Reinaldos, M., Teyssier, D., Altmann, M., Andrae, R., Audard, M., Bellas-Velidis, I., Benson, K., Berthier, J., Blomme, R., Burgess, P., Busso, G., Carry, B., Cellino, A., Clementini, G., Clotet, M., Creevey, O., Davidson, M., DeRidder, J., Delchambre, L., Dell'Oro, A., Ducourant, C., Fernández-Hernández, J., Fouesneau, M., Frémat, Y., Galluccio, L., García-Torres, M., González-Núñez, J., González-Vidal, J. J., Gosset, E., Guy, L. P., Halbwachs, J. -L., Hambly, N. C., Harrison, D. L., Hernández, J., Hestroffer, D., Hodgkin, S. T., Hutton, A., Jasniewicz, G., Jean-Antoine-Piccolo, A., Jordan, S., Korn, A. J., Krone-Martins, A., Lanzafame, A. C., Lebzelter, T., Löffler, W., Manteiga, M., Marrese, P. M., Martín-Fleitas, J. M., Moitinho, A., Mora, A., Muinonen, K., Osinde, J., Pancino, E., Pauwels, T., Petit, J. -M., Recio-Blanco, A., Richards, P. J., Rimoldini, L., Robin, A. C., Sarro, L. M., Siopis, C., Smith, M., Sozzetti, A., Süveges, M., Torra, J., vanReeven, W., Abbas, U., Aramburu, A. Abreu, Accart, S., Aerts, C., Altavilla, G., Álvarez, M. A., Alvarez, R., Alves, J., Anderson, R. I., Andrei, A. H., Varela, E. Anglada, Antiche, E., Antoja, T., Arcay, B., Astraatmadja, T. L., Bach, N., Baker, S. G., Balaguer-Núñez, L., Balm, P., Barache, C., Barata, C., Barbato, D., Barblan, F., Barklem, P. S., Barrado, D., Barros, M., Muñoz, S. Bartholomé, Bassilana, J. -L., Becciani, U., Bellazzini, M., Berihuete, A., Bertone, S., Bianchi, L., Bienaymé, O., Blanco-Cuaresma, S., Boch, T., Boeche, C., Bombrun, A., Borrachero, R., Bouquillon, S., Bourda, G., Bragaglia, A., Bramante, L., Breddels, M. A., Brouillet, N., Brüsemeister, T., Brugaletta, E., Bucciarelli, B., Burlacu, A., Busonero, D., Butkevich, A. G., Buzzi, R., Caffau, E., Cancelliere, R., Cannizzaro, G., Carballo, R., Carlucci, T., Carrasco, J. M., Casamiquela, L., Castellani, M., Castro-Ginard, A., Charlot, P., Chemin, L., Chiavassa, A., Cocozza, G., Costigan, G., Cowell, S., Crifo, F., Crosta, M., Crowley, C., Cuypers, J., Dafonte, C., Damerdji, Y., Dapergolas, A., David, P., David, M., deLaverny, P., DeLuise, F., DeMarch, R., deMartino, D., deSouza, R., deTorres, A., Debosscher, J., delPozo, E., Delbo, M., Delgado, A., Delgado, H. E., Diakite, S., Diener, C., Distefano, E., Dolding, C., Drazinos, P., Durán, J., Edvardsson, B., Enke, H., Eriksson, K., Esquej, P., Bontemps, G. Eynard, Fabre, C., Fabrizio, M., Faigler, S., Falcão, A. J., Casas, M. Farràs, Federici, L., Fedorets, G., Fernique, P., Figueras, F., Filippi, F., Findeisen, K., Fonti, A., Fraile, E., Fraser, M., Frézouls, B., Gai, M., Galleti, S., Garabato, D., García-Sedano, F., Garofalo, A., Garralda, N., Gavel, A., Gavras, P., Gerssen, J., Geyer, R., Giacobbe, P., Gilmore, G., Girona, S., Giuffrida, G., Glass, F., Gomes, M., Granvik, M., Gueguen, A., Guerrier, A., Guiraud, J., Gutiérrez-Sánchez, R., Haigron, R., Hatzidimitriou, D., Hauser, M., Haywood, M., Heiter, U., Helmi, A., Heu, J., Hilger, T., Hobbs, D., Hofmann, W., Holland, G., Huckle, H. E., Hypki, A., Icardi, V., Janßen, K., JevardatdeFombelle, G., Jonker, P. G., Juhász, Á. L., Julbe, F., Karampelas, A., Kewley, A., Klar, J., Kochoska, A., Kohley, R., Kolenberg, K., Kontizas, M., Kontizas, E., Koposov, S. E., Kordopatis, G., Kostrzewa-Rutkowska, Z., Koubsky, P., Lambert, S., Lanza, A. F., Lasne, Y., Lavigne, J. -B., LeFustec, Y., LePoncin-Lafitte, C., Lebreton, Y., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Lenhardt, H., Leroux, F., Liao, S., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., López, M., Managau, S., Mann, R. G., Mantelet, G., Marchal, O., Marchant, J. M., Marconi, M., Marinoni, S., Marschalkó, G., Marshall, D. J., Martino, M., Marton, G., Mary, N., Massari, D., Matijevič, G., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Molina, D., Molinaro, R., Molnár, L., Montegriffo, P., Mor, R., Morbidelli, R., Morel, T., Morris, D., Mulone, A. F., Muraveva, T., Musella, I., Nelemans, G., Nicastro, L., Noval, L., O'Mullane, W., Ordénovic, C., Ordóñez-Blanco, D., Osborne, P., Pagani, C., Pagano, I., Pailler, F., Palacin, H., Palaversa, L., Panahi, A., Pawlak, M., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poggio, E., Poujoulet, E., Prša, A., Pulone, L., Racero, E., Ragaini, S., Rambaux, N., Ramos-Lerate, M., Regibo, S., Reylé, C., Riclet, F., Ripepi, V., Riva, A., Rivard, A., Rixon, G., Roegiers, T., Roelens, M., Romero-Gómez, M., Rowell, N., Royer, F., Ruiz-Dern, L., Sadowski, G., Sellés, T. Sagristà, Sahlmann, J., Salgado, J., Salguero, E., Sanna, N., Santana-Ros, T., Sarasso, M., Savietto, H., Schultheis, M., Sciacca, E., Segol, M., Segovia, J. C., Ségransan, D., Shih, I-C., Siltala, L., Silva, A. F., Smart, R. L., Smith, K. W., Solano, E., Solitro, F., Sordo, R., SoriaNieto, S., Souchay, J., Spagna, A., Spoto, F., Stampa, U., Steele, I. A., Steidelmüller, H., Stephenson, C. A., Stoev, H., Suess, F. F., Surdej, J., Szabados, L., Szegedi-Elek, E., Tapiador, D., Taris, F., Tauran, G., Taylor, M. B., Teixeira, R., Terrett, D., Teyssandier, P., Thuillot, W., Titarenko, A., TorraClotet, F., Turon, C., Ulla, A., Utrilla, E., Uzzi, S., Vaillant, M., Valentini, G., Valette, V., vanElteren, A., Van Hemelryck, E., Vaschetto, M., Vecchiato, A., Veljanoski, J., Viala, Y., Vicente, D., Vogt, S., vonEssen, C., Voss, H., Votruba, V., Voutsinas, S., Walmsley, G., Weiler, M., Wertz, O., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Žerjal, M., Ziaeepour, H., Zorec, J., Zschocke, S., Zucker, S., Zurbach, C., and Zwitter, T.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We highlight the power of the Gaia DR2 in studying many fine structures of the Hertzsprung-Russell diagram (HRD). Gaia allows us to present many different HRDs, depending in particular on stellar population selections. We do not aim here for completeness in terms of types of stars or stellar evolutionary aspects. Instead, we have chosen several illustrative examples. We describe some of the selections that can be made in Gaia DR2 to highlight the main structures of the Gaia HRDs. We select both field and cluster (open and globular) stars, compare the observations with previous classifications and with stellar evolutionary tracks, and we present variations of the Gaia HRD with age, metallicity, and kinematics. Late stages of stellar evolution such as hot subdwarfs, post-AGB stars, planetary nebulae, and white dwarfs are also analysed, as well as low-mass brown dwarf objects. The Gaia HRDs are unprecedented in both precision and coverage of the various Milky Way stellar populations and stellar evolutionary phases. Many fine structures of the HRDs are presented. The clear split of the white dwarf sequence into hydrogen and helium white dwarfs is presented for the first time in an HRD. The relation between kinematics and the HRD is nicely illustrated. Two different populations in a classical kinematic selection of the halo are unambiguously identified in the HRD. Membership and mean parameters for a selected list of open clusters are provided. They allow drawing very detailed cluster sequences, highlighting fine structures, and providing extremely precise empirical isochrones that will lead to more insight in stellar physics. Gaia DR2 demonstrates the potential of combining precise astrometry and photometry for large samples for studies in stellar evolution and stellar population and opens an entire new area for HRD-based studies., Comment: Published in the A&A Gaia Data Release 2 special issue. Tables 2 and A.4 corrected. Tables available at http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A10
Published: 2018
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33. The disc origin of the Milky Way bulge: Dissecting the chemo-morphological relations using N-body simulations and APOGEE

Author: Fragkoudi, F., Di Matteo, P., Haywood, M., Schultheis, M., Khoperskov, S, Gómez, A., and Combes, F.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: There is a long-standing debate on the origin of the metal-poor stellar populations of the Milky Way (MW) bulge, with the two leading scenarios being that these populations are either i) part of a classical metal-poor spheroid or ii) the same population as the chemically defined thick disc seen at the Solar neighbourhood. Here we test whether the latter scenario can reproduce the observed chemical properties of the MW bulge. To do so we compare an N-body simulation of a composite (thin+thick) stellar disc -- which evolves secularly to form a bar and a boxy/peanut (b/p) bulge -- to data from APOGEE DR13. This model, in which the thick disc is massive and centrally concentrated, can reproduce the morphology of the metal-rich and metal-poor stellar populations in the bulge, as well as the mean metallicity and [$\alpha$/Fe] maps as obtained from the APOGEE data. It also reproduces the trends, in both longitude and latitude, of the bulge metallicity distribution function (MDF). Additionally, we show that the model predicts small but measurable azimuthal metallicity variations in the inner disc due to the differential mapping of the thin and thick disc in the bar. We therefore see that the chemo-morphological relations of stellar populations in the MW bulge are naturally reproduced by mapping the thin and thick discs of the inner MW into a b/p., Comment: 15 pages, 14 figures. Accepted for publication in A&A
Published: 2018
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34. Stellar metallicity variations across spiral arms in disk galaxies with multiple populations

Author: Khoperskov, S., Di Matteo, P., Haywood, M., and Combes, F.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: This letter studies the formation of azimuthal metallicity variations in the disks of spiral galaxies in the absence of initial radial metallicity gradients. Using high-resolution $N$-body simulations, we model composite stellar discs, made of kinematically cold and hot stellar populations, and study their response to spiral arm perturbations. We find that, as expected, disk populations with different kinematics respond differently to a spiral perturbation, with the tendency for dynamically cooler populations to show a larger fractional contribution to spiral arms than dynamically hotter populations. By assuming a relation between kinematics and metallicity, namely the hotter the population, the more metal-poor it is, this differential response to the spiral arm perturbations naturally leads to azimuthal variations in the mean metallicity of stars in the simulated disk. Thus, azimuthal variations in the mean metallicity of stars across a spiral galaxy are not necessarily a consequence of the reshaping, by radial migration, of an initial radial metallicity gradient. They indeed arise naturally also in stellar disks which have initially only a negative vertical metallicity gradient., Comment: 5 pages, 6 figures, Accepted for publication in A&A Letters
Published: 2018
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35. What the Milky Way bulge reveals about the initial metallicity gradients in the disc

Author: Fragkoudi, F., Di Matteo, P., Haywood, M., Khoperskov, S., Gómez, A., Schultheis, M., Combes, F., and Semelin, B.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We examine the metallicity trends in the Milky Way (MW) bulge - using APOGEE DR13 data - and explore their origin by comparing two N-body models of isolated galaxies which develop a bar and a boxy/peanut (b/p) bulge. Both models have been proposed as scenarios for reconciling a disc origin of the MW bulge with a negative vertical metallicity gradient. The first model is a superposition of co-spatial, i.e. overlapping, disc populations with different scaleheights, kinematics and metallicities. In this model the thick, metal-poor, and centrally concentrated disc populations contribute significantly to the stellar mass budget in the inner galaxy. The second model is a single disc with an initial steep radial metallicity gradient, which is mapped by the bar into the b/p bulge in such a way that the vertical metallicity gradient of the MW bulge is reproduced -- as shown already in previous works in the literature. However, as we show here, the latter model does not reproduce the positive longitudinal metallicity gradient of the inner disc, nor the metal-poor innermost regions of the Bulge seen in the data. On the other hand, the model with co-spatial thin and thick disc populations reproduces all the aforementioned trends. We therefore see that it is possible to reconcile a (primarily) disc origin for the MW bulge with the observed trends in metallicity by mapping the inner thin and thick discs of the MW into a b/p. For this scenario to reproduce the observations, the $\alpha$-enhanced, metal-poor, thick disc populations must have a significant mass contribution in the inner regions -- as has been suggested for the Milky Way., Comment: 6 pages, accepted for publication in A&A Letters
Published: 2017
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36. Teaching Case: Making the Grade: Using COBIT to Study Computer Crime at Bucks County Community College (Pennsylvania)

Author: Haywood, M. Elizabeth
Abstract: ISACA, a non-profit, independent association that advocates for professionals involved in information security, assurance, risk management, and governance, recently updated its IT governance framework, Control Objectives for Information and Related Technology (COBIT). COBIT 2019 presents a logical approach to information technology and policy issues. Using a recent real-world computer crime that occurred at a community college, students address breaches of various COBIT components. Students then recommend approaches to minimize the risks and vulnerabilities that expose this school and others. This current case familiarizes students with COBIT's components and the value it provides.
Published: 2021

37. Bar quenching in gas-rich galaxies

Author: Khoperskov, S., Haywood, M., Di Matteo, P., Lehnert, M. D., and Combes, F.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Galaxy surveys have suggested that rapid and sustained decrease in the star-formation rate, "quenching", in massive disk galaxies is frequently related to the presence of a bar. Optical and near-IR observations reveal that nearly 60% of disk galaxies in the local universe are barred, thus it is important to understand the relationship between bars and star formation in disk galaxies. Recent observational results imply that the Milky Way quenched about 9-10 Gyr ago, at the transition between the cessation of the growth of the kinematically hot, old, metal-poor thick disk and the kinematically colder, younger, and more metal-rich thin disk. Although perhaps coincidental, the quenching episode could also be related to the formation of the bar. To explore the relation between bar formation and star formation in gas rich galaxies quantitatively, we simulated gas-rich disk isolated galaxies. Our simulations include prescriptions for star formation, stellar feedback, and for regulating the multi-phase interstellar medium. We find that the action of stellar bar efficiently quenches star formation, reducing the star-formation rate by a factor of 10 in less than 1 Gyr. Analytical and self-consistent galaxy simulations with bars suggest that the action of the stellar bar increases the gas random motions within the co-rotation radius of the bar. Indeed, we detect an increase in the gas velocity dispersion up to 20-35 km/s at the end of the bar formation phase. The star-formation efficiency decreases rapidly, and in all of our models, the bar quenches the star formation in the galaxy. The star-formation efficiency is much lower in simulated barred compared to unbarred galaxies and more rapid bar formation implies more rapid quenching., Comment: 17 pages, 17 figure, accepted for publication in A&A
Published: 2017
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38. Effects of the selection function on metallicity trends in spectroscopic surveys of the Milky Way

Author: Nandakumar, G., Schultheis, M., Hayden, M., Rojas-Arriagada, A., Kordopatis, G., and Haywood, M.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We investigate here the effect of the selection function on the metallicity distribution function (MDF) and on the vertical metallicity gradient by studying similar lines of sight using four different spectroscopic surveys (APOGEE, LAMOST, RAVE, and Gaia-ESO), which have different targeting strategies and therefore different selection functions. We use common fields between the spectroscopic surveys of APOGEE, LAMOST, RAVE (ALR) and APOGEE, RAVE, Gaia-ESO (AGR) and use two stellar population synthesis models, GALAXIA and TRILEGAL, to create mock fields for each survey. We apply the selection function in the form of colour and magnitude cuts of the respective survey to the mock fields to replicate the observed source sample. We make a basic comparison between the models to check which best reproduces the observed sample distribution. We carry out a quantitative comparison between the synthetic MDF from the mock catalogues using both models to understand the effect of the selection function on the MDF and on the vertical metallicity gradient. Using both models, we find a negligible effect of the selection function on the MDF for APOGEE, LAMOST, and RAVE. We find a negligible selection function effect on the vertical metallicity gradients as well, though GALAXIA and TRILEGAL have steeper and shallower slopes, respectively, than the observed gradient. After applying correction terms on the metallicities of RAVE and LAMOST with respect to our reference APOGEE sample, our observed vertical metallicity gradients between the four surveys are consistent within 1-sigma. We also find consistent gradient for the combined sample of all surveys in ALR and AGR. We estimated a mean vertical metallicity gradient of -0.241+/-0.028 dex kpc-1. There is a significant scatter in the estimated gradients in the literature, but our estimates are within their ranges., Comment: 16 pages, 11 figures, Accepted for publication in A&A
Published: 2017
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39. PLATO as it is: a legacy mission for Galactic archaeology

Author: Miglio, A., Chiappini, C., Mosser, B., Davies, G. R., Freeman, K., Girardi, L., Jofre, P., Kawata, D., Rendle, B. M., Valentini, M., Casagrande, L., Chaplin, W. J., Gilmore, G., Hawkins, K., Holl, B., Appourchaux, T., Belkacem, K., Bossini, D., Brogaard, K., Goupil, M. -J., Montalban, J., Noels, A., Anders, F., Rodrigues, T., Piotto, G., Pollacco, D., Rauer, H., Prieto, C. Allende, Avelino, P. P., Babusiaux, C., Barban, C., Barbuy, B., Basu, S., Baudin, F., Benomar, O., Bienayme, O., Binney, J., Bland-Hawthorn, J., Bressan, A., Cacciari, C., Campante, T. L., Cassisi, S., Christensen-Dalsgaard, J., Combes, F., Creevey, O., Cunha, M. S., de Jong, R. S., de Laverny, P., Degl'Innocenti, S., Deheuvels, S., Depagne, E., DeRidder, J., DiMatteo, P., Di Mauro, M. P., Dupret, M. -A., Eggenberger, P., Elsworth, Y., Famaey, B., Feltzing, S., Garcia, R. A., Gerhard, O., Gibson, B. K., Gizon, L., Haywood, M., Handberg, R., Heiter, U., Hekker, S., Huber, D., Ibata, R., Katz, D., Kawaler, S. D., Kjeldsen, H., Kurtz, D. W., Lagarde, N., Lebreton, Y., Lund, M. N., Majewski, S. R., Marigo, P., Martig, M., Mathur, S., Minchev, I., Morel, T., Ortolani, S., Pinsonneault, M. H., Plez, B., Moroni, P. G. Prada, Pricopi, D., Recio-Blanco, A., Reyle, C., Robin, A., Roxburgh, I. W., Salaris, M., Santiago, B. X., Schiavon, R., Serenelli, A., Sharma, S., Aguirre, V. Silva, Soubiran, C., Steinmetz, M., Stello, D., Strassmeier, K. G., Ventura, P., Ventura, R., Walton, N. A., and Worley, C. C.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: Deciphering the assembly history of the Milky Way is a formidable task, which becomes possible only if one can produce high-resolution chrono-chemo-kinematical maps of the Galaxy. Data from large-scale astrometric and spectroscopic surveys will soon provide us with a well-defined view of the current chemo-kinematical structure of the Milky Way, but will only enable a blurred view on the temporal sequence that led to the present-day Galaxy. As demonstrated by the (ongoing) exploitation of data from the pioneering photometric missions CoRoT, Kepler, and K2, asteroseismology provides the way forward: solar-like oscillating giants are excellent evolutionary clocks thanks to the availability of seismic constraints on their mass and to the tight age-initial-mass relation they adhere to. In this paper we identify five key outstanding questions relating to the formation and evolution of the Milky Way that will need precise and accurate ages for large samples of stars to be addressed, and we identify the requirements in terms of number of targets and the precision on the stellar properties that are needed to tackle such questions. By quantifying the asteroseismic yields expected from PLATO for red-giant stars, we demonstrate that these requirements are within the capabilities of the current instrument design, provided that observations are sufficiently long to identify the evolutionary state and allow robust and precise determination of acoustic-mode frequencies. This will allow us to harvest data of sufficient quality to reach a 10% precision in age. This is a fundamental pre-requisite to then reach the more ambitious goal of a similar level of accuracy, which will only be possible if we have to hand a careful appraisal of systematic uncertainties on age deriving from our limited understanding of stellar physics, a goal which conveniently falls within the main aims of PLATO's core science., Comment: 17 pages, 9 figures, accepted for publication in Astronomical Notes
Published: 2017
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40. Gaia Data Release 1. Testing the parallaxes with local Cepheids and RR Lyrae stars

Author: Gaia Collaboration, Clementini, G., Eyer, L., Ripepi, V., Marconi, M., Muraveva, T., Garofalo, A., Sarro, L. M., Palmer, M., Luri, X., Molinaro, R., Rimoldini, L., Szabados, L., Musella, I., Anderson, R. I., 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., Jansen, F., Jordi, C., Klioner, S. A., Lammers, U., Lindegren, L., Mignard, F., 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., Drimmel, R., Høg, E., Katz, D., Lattanzi, M. G., O'Mullane, W., Grebel, E. K., Holland, A. D., Huc, C., Passot, X., Perryman, M., Bramante, L., Cacciari, C., Castañeda, J., Chaoul, L., Cheek, N., De Angeli, F., Fabricius, C., Guerra, R., Hernández, J., Jean-Azntoine-Piccolo, A., Masana, E., Messineo, R., Mowlavi, N., Nienartowicz, K., Ordóñez-Blanco, D., Panuzzo, P., Portell, J., Richards, P. J., Riello, M., Seabroke, G. M., Tanga, P., Thévenin, 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., Cowell, S., Creevey, O., Cuypers, J., Davidson, M., De Ridder, J., de Torres, A., Delchambre, L., Dell'Oro, A., Ducourant, C., Frémat, Y., García-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, A. 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., 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., Álvarez, M. A., Alves, J., Andrei, A. H., Varela, E. Anglada, Antiche, E., Antoja, T., Antón, S., Arcay, B., Bach, N., Baker, S. G., Balaguer-Núñez, L., Barache, C., Barata, C., Barbier, A., Barblan, F., Navascués, D. Barrado y, Barros, M., Barstow, M. A., Becciani, U., Bellazzini, M., García, A. Bello, Belokurov, V., Bendjoya, P., Berihuete, A., Bianchi, L., Bienaymé, 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., Brüsemeister, 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 Souza, R., Debosscher, J., del Pozo, E., Delbo, M., Delgado, A., Delgado, H. E., Di Matteo, P., Diakite, S., Distefano, E., Dolding, C., Anjos, S. Dos, Drazinos, P., Durán, J., Dzigan, Y., Edvardsson, B., Enke, H., Evans, N. W., Bontemps, G. Eynard, Fabre, C., Fabrizio, M., Faigler, S., Falcão, A. J., Casas, M. Farràs, Federici, L., Fedorets, G., Fernández-Hernánde, 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., García-Sedano, F., Garralda, N., Gavras, P., Gerssen, J., Geyer, R., Gilmore, G., Girona, S., Giuffrida, G., Gomes, M., González-Marcos, A., González-Núñez, J., González-Vidal, J. J., Granvik, M., Guerrier, A., Guillout, P., Guiraud, J., Gúrpide, A., Gutiérrez-Sánchez, R., Guy, L. P., Haigron, R., Hatzidimitriou, D., Haywood, M., Heiter, U., Helmi, A., Hobbs, D., Hofmann, W., Holl, B., Holland, G., Hunt, J. A. S., Hypki, A., Icardi, V., Irwin, M., de Fombelle, G. Jevardat, Jofré, 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., Poncin-Lafitte, C. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Lemaitre, V., Lenhardt, H., Leroux, F., Liao, S., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Löffler, W., López, M., Lorenz, D., MacDonald, I., Fernandes, T. Magalhães, Managau, S., Mann, R. G., Mantelet, G., Marchal, O., Marchant, J. M., Marinoni, S., Marrese, P. M., Marschalkó, G., Marshall, D. J., Martín-Fleitas, J. M., Martino, M., Mary, N., Matijevič, G., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Miranda, B. M. H., Molina, D., Molinaro, M., Molnár, L., Moniez, M., Montegriffo, P., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morgenthaler, S., Morris, D., Mulone, A. F., Narbonne, J., Nelemans, G., Nicastro, L., Noval, L., Ordénovic, C., Ordieres-Meré, J., Osborne, P., Pagani, C., Pagano, I., Pailler, F., Palacin, H., Palaversa, L., Parsons, P., Pecoraro, M., Pedrosa, R., Pentikäinen, H., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poujoulet, E., Prša, A., Pulone, L., Ragaini, S., Rago, S., Rambaux, N., Ramos-Lerate, M., Ranalli, P., Rauw, G., Read, A., Regibo, S., Reylé, C., Ribeiro, R. A., Riva, A., Rixon, G., Roelens, M., Romero-Gómez, M., Rowell, N., Royer, F., Ruiz-Dern, L., Sadowski, G., Sellés, T. Sagristà, 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., Steidelmüller, H., Stephenson, C. A., Stoev, H., Suess, F. F., Süveges, M., Surdej, J., 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, Ł., Yoldas, A., Žerjal, M., Zucker, S., Zurbach, C., Zwitter, T., Alecu, A., Allen, M., Prieto, C. Allende, Amorim, A., Anglada-Escudé, 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., Chéreau, F., Corcione, L., Darmigny, E., de Boer, K. S., de Teodoro, P., de Zeeuw, P. T., Luche, C. Delle, Domingues, C. D., Dubath, P., Fodor, F., Frézouls, B., Fries, A., Fustes, D., Fyfe, D., Gallardo, E., Gallegos, J., Gardiol, D., Gebran, M., Gomboc, A., Gómez, 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, O., 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, T., O'Flaherty, K. S., Ocvirk, P., Sanz, A. Olias, Ortiz, P., Osorio, J., Oszkiewicz, D., Ouzounis, A., Park, P., Pasquato, E., Peltzer, C., Peralta, J., Péturaud, 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., Straižys, 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.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: Parallaxes for 331 classical Cepheids, 31 Type II Cepheids and 364 RR Lyrae stars in common between Gaia and the Hipparcos and Tycho-2 catalogues are published in Gaia Data Release 1 (DR1) as part of the Tycho-Gaia Astrometric Solution (TGAS). In order to test these first parallax measurements of the primary standard candles of the cosmological distance ladder, that involve astrometry collected by Gaia during the initial 14 months of science operation, we compared them with literature estimates and derived new period-luminosity ($PL$), period-Wesenheit ($PW$) relations for classical and Type II Cepheids and infrared $PL$, $PL$-metallicity ($PLZ$) and optical luminosity-metallicity ($M_V$-[Fe/H]) relations for the RR Lyrae stars, with zero points based on TGAS. The new relations were computed using multi-band ($V,I,J,K_{\mathrm{s}},W_{1}$) photometry and spectroscopic metal abundances available in the literature, and applying three alternative approaches: (i) by linear least squares fitting the absolute magnitudes inferred from direct transformation of the TGAS parallaxes, (ii) by adopting astrometric-based luminosities, and (iii) using a Bayesian fitting approach. TGAS parallaxes bring a significant added value to the previous Hipparcos estimates. The relations presented in this paper represent first Gaia-calibrated relations and form a "work-in-progress" milestone report in the wait for Gaia-only parallaxes of which a first solution will become available with Gaia's Data Release 2 (DR2) in 2018., Comment: 29 pages, 25 figures. Accepted for publication by A&A
Published: 2017
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41. Bars & boxy/peanut bulges in thin & thick discs: I. Morphology and line-of-sight velocities of a fiducial model

Author: Fragkoudi, F., Di Matteo, P., Haywood, M., Gómez, A., Combes, F., Katz, D., and Semelin, B.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We explore trends in the morphology and line-of-sight (los) velocity of stellar populations in the inner regions of disc galaxies, using N-body simulations with both a thin (kinematically cold) and a thick (kinematically hot) disc which form a bar and boxy/peanut (b/p) bulge. The bar in the thin disc component is $\sim$50\% stronger than the thick disc bar and is more elongated, with an axis ratio almost half that of the thick disc bar. The thin disc b/p bulge has a pronounced X-shape, while the thick disc b/p is weaker with a rather boxy shape. This leads to the signature of the b/p bulge in the thick disc to be weaker and further away from the plane than in the thin disc. Regarding the kinematics, we find that the los velocity of thick disc stars in the outer parts of the b/p bulge can be \emph{larger} than that of thin disc stars, by up to 40\% and 20\% for side-on and Milky Way-like orientations of the bar respectively. This is due to the different orbits followed by thin and thick disc stars in the bar-b/p region, which are affected by the fact that: i) thin disc stars are trapped more efficiently in the bar - b/p instability and thus lose more angular momentum than their thick disc counterparts and ii) thick disc stars have large radial excursions and therefore stars from large radii with high angular momenta can be found in the bar region. We also find that the difference between the los velocities of the thin and thick disc in the b/p bulge ($\Delta v_{los}$) correlates with the initial difference between the radial velocity dispersions of the two discs ($\Delta \sigma$) . We therefore conclude that stars in the bar - b/p bulge will have considerably different morphologies and kinematics depending on the kinematic properties of the disc population they originate from., Comment: Accepted for publication in A&A. 15 pages (2 page appendix). 16 figures
Published: 2017
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42. Gaia Data Release 1. Open cluster astrometry: performance, limitations, and future prospects

Author: Gaia Collaboration, van Leeuwen, F., Vallenari, A., Jordi, C., Lindegren, L., Bastian, U., Prusti, T., de Bruijne, J. H. J., Brown, A. G. A., Babusiaux, C., Bailer-Jones, C. A. L., Biermann, M., Evans, D. W., Eyer, L., Jansen, F., Klioner, S. A., Lammers, U., Luri, X., Mignard, F., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Siddiqui, H. I., Soubiran, C., Valette, V., Walton, N. A., Aerts, C., Arenou, F., Cropper, M., Drimmel, R., Høg, E., Katz, D., Lattanzi, M. G., O'Mullane, W., Grebel, E. K., Holland, A. D., Huc, C., Passot, X., Perryman, M., Bramante, L., Cacciari, C., Castañeda, J., Chaoul, L., Cheek, N., De Angeli, F., Fabricius, C., Guerra, R., Hernández, J., Jean-Antoine-Piccolo, A., Masana, E., Messineo, R., Mowlavi, N., Nienartowicz, K., Ordóñez-Blanco, D., Panuzzo, P., Portell, J., Richards, P. J., Riello, M., Seabroke, G. M., Tanga, P., Thévenin, 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., Frémat, Y., García-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, A. 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., Álvarez, M. A., Alves, J., Anderson, R. I., Andrei, A. H., Varela, E. Anglada, Antiche, E., Antoja, T., Antón, S., Arcay, B., Bach, N., Baker, S. G., Balaguer-Núñez, L., Barache, C., Barata, C., Barbier, A., Barblan, F., Navascués, D. Barrado y, Barros, M., Barstow, M. A., Becciani, U., Bellazzini, M., García, A. Bello, Belokurov, V., Bendjoya, P., Berihuete, A., Bianchi, L., Bienaymé, 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., Brüsemeister, 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., Anjos, S. Dos, Drazinos, P., Durán, J., Dzigan, Y., Edvardsson, B., Enke, H., Evans, N. W., Bontemps, G. Eynard, Fabre, C., Fabrizio, M., Faigler, S., Falcão, A. J., Casas, M. Farràs, Federici, L., Fedorets, G., Fernández-Hernández, 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., García-Sedano, F., Garofalo, A., Garralda, N., Gavras, P., Gerssen, J., Geyer, R., Gilmore, G., Girona, S., Giuffrida, G., Gomes, M., González-Marcos, A., González-Núñez, J., González-Vidal, J. J., Granvik, M., Guerrier, A., Guillout, P., Guiraud, J., Gúrpide, A., Gutiérrez-Sánchez, R., Guy, L. P., Haigron, R., Hatzidimitriou, D., Haywood, M., Heiter, U., Helmi, A., Hobbs, D., Hofmann, W., Holl, B., Holland, G., Hunt, J. A. S., Hypki, A., Icardi, V., Irwin, M., de Fombelle, G. Jevardat, Jofré, 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., Poncin-Lafitte, C. Le, Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Lemaitre, V., Lenhardt, H., Leroux, F., Liao, S., Licata, E., Lindstrøm, H. E. P., Lister, T. A., Livanou, E., Lobel, A., Löffer, W., López, M., Lorenz, D., MacDonald, I., Fernandes, T. Magalhães, Managau, S., Mann, R. G., Mantelet, G., Marchal, O., Marchant, J. M., Marconi, M., Marinoni, S., Marrese, P. M., Marschalkó, G., Marshall, D. J., Martín-Fleitas, J. M., Martino, M., Mary, N., Matijevič, G., Mazeh, T., McMillan, P. J., Messina, S., Michalik, D., Millar, N. R., Miranda, B. M. H., Molina, D., Molinaro, R., Molinaro, M., Molnár, L., Moniez, M., Montegrio, 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., Ordénovic, C., Ordieres-Meré, J., Osborne, P., Pagani, C., Pagano, I., Pailler, F., Palacin, H., Palaversa, L., Parsons, P., Pecoraro, M., Pedrosa, R., Pentikäinen, H., Pichon, B., Piersimoni, A. M., Pineau, F. -X., Plachy, E., Plum, G., Poujoulet, E., Prša, A., Pulone, L., Ragaini, S., Rago, S., Rambaux, N., Ramos-Lerate, M., Ranalli, P., Rauw, G., Read, A., Regibo, S., Reylé, C., Ribeiro, R. A., Rimoldini, L., Ripepi, V., Riva, A., Rixon, G., Roelens, M., Romero-Gómez, M., Rowell, N., Royer, F., Ruiz-Dern, L., Sadowski, G., Sellés, T. Sagristà, 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., Steidelmüller, H., Stephenson, C. A., Stoev, H., Suess, F. F., Süveges, 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., Weingril, K., Wevers, T., Wyrzykowski, Ł., Yoldas, A., Žerjal, M., Zucker, S., Zurbach, C., Zwitter, T., Alecu, A., Allen, M., Prieto, C. Allende, Amorim, A., Anglada-Escudé, G., Arsenijevic, V., Azaz, S., Balm, P., Beck, M., Bernsteiny, H. -H., Bigot, L., Bijaoui, A., Blasco, C., Bonfigli, M., Bono, G., Boudreault, S., Bressan, A., Brown, S., Brunet, P. -M., Bunclarky, P., Buonanno, R., Butkevich, A. G., Carret, C., Carrion, C., Chemin, L., Chéreau, F., Corcione, L., Darmigny, E., de Boer, K. S., de Teodoro, P., de Zeeuw, P. T., Luche, C. Delle, Domingues, C. D., Dubath, P., Fodor, F., Frézouls, B., Fries, A., Fustes, D., Fyfe, D., Gallardo, E., Gallegos, J., Gardio, D., Gebran, M., Gomboc, A., Gómez, 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, O., 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, T., O'Flaherty, K. S., Ocvirk, P., Sanz, A. Olias, Ortiz, P., Osorio, J., Oszkiewicz, D., Ouzounis, A., Palmer, M., Park, P., Pasquato, E., Peltzer, C., Peralta, J., Péturaud, F., Pieniluoma, T., Pigozzi, E., Poelsy, 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., Straižys, 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.
Subjects: Astrophysics - Solar and Stellar Astrophysics
Abstract: Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 positions in 1991.25 as prior information. Aims. We investigate the scientific potential and limitations of the TGAS component by means of the astrometric data for open clusters. Methods. Mean cluster parallax and proper motion values are derived taking into account the error correlations within the astrometric solutions for individual stars, an estimate of the internal velocity dispersion in the cluster, and, where relevant, the effects of the depth of the cluster along the line of sight. Internal consistency of the TGAS data is assessed. Results. Values given for standard uncertainties are still inaccurate and may lead to unrealistic unit-weight standard deviations of least squares solutions for cluster parameters. Reconstructed mean cluster parallax and proper motion values are generally in very good agreement with earlier Hipparcos-based determination, although the Gaia mean parallax for the Pleiades is a significant exception. We have no current explanation for that discrepancy. Most clusters are observed to extend to nearly 15 pc from the cluster centre, and it will be up to future Gaia releases to establish whether those potential cluster-member stars are still dynamically bound to the clusters. Conclusions. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. A combined HR diagram shows the same features as observed before using the Hipparcos data, with clearly increased luminosities for older A and F dwarfs., Comment: Accepted for publication by A&A. 21 pages main text plus 46 pages appendices. 34 figures main text, 38 figures appendices. 8 table in main text, 19 tables in appendices
Published: 2017
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43. On the kinematic detection of accreted streams in the Gaia era: a cautionary tale

Author: Jean-Baptiste, I., Di Matteo, P., Haywood, M., Gomez, A., Montuori, M., Combes, F., and Semelin, B.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The $\Lambda$CDM cosmological scenario predicts that our Galaxy should contain hundreds of stellar streams at the solar vicinity, fossil relics of the merging history of the Milky Way and more generally of the hierarchical growth of galaxies. Because of the mixing time scales in the inner Galaxy, it has been claimed that these streams should be difficult to detect in configuration space but can still be identifiable in kinematic-related spaces like the energy/angular momenta spaces, E-Lz and Lperp-Lz, or spaces of orbital/velocity parameters. By means of high-resolution, dissipationless N-body simulations, containing between 25$\times10^6$ and 35$\times10^6$ particles, we model the accretion of a series of up to four 1:10 mass ratio satellites then up to eight 1:100 satellites and we search systematically for the signature of these accretions in these spaces. In all spaces considered (1) each satellite gives origin to several independent overdensities; (2) overdensities of multiple satellites overlap; (3) satellites of different masses can produce similar substructures; (4) the overlap between the in-situ and the accreted population is considerable everywhere; (5) in-situ stars also form substructures in response to the satellite(s) accretion. These points are valid even if the search is restricted to kinematically-selected halo stars only. As we are now entering the 'Gaia era', our results warn that an extreme caution must be employed before interpreting overdensities in any of those spaces as evidence of relics of accreted satellites. Reconstructing the accretion history of our Galaxy will require a substantial amount of accurate spectroscopic data, that, complemented by the kinematic information, will possibly allow us to (chemically) identify accreted streams and measure their orbital properties. (abridged), Comment: Accepted on A&A. A high-resolution version of the paper is available at http://aramis.obspm.fr/~paola/ELZ/Elz.pdf
Published: 2016
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44. Hiding its age: the case for a younger bulge

Author: Haywood, M., Di Matteo, P., Snaith, O., and Calamida, A.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The determination of the age of the bulge has led to two contradictory results. On the one side, the color-magnitude diagrams in different bulge fields seem to indicate a uniformly old ($>$10 Gyr) population. On the other side, individual ages derived from dwarfs observed through microlensing events seem to indicate a large spread, from $\sim$ 2 to $\sim$ 13 Gyr. Because the bulge is now recognised as being mainly a boxy peanut-shaped bar, it is suggested that disk stars are one of its main constituents, and therefore also stars with ages significantly younger than 10 Gyr. Other arguments as well point to the fact that the bulge cannot be exclusively old, and in particular cannot be a burst population, as it is usually expected if the bulge was the fossil remnant of a merger phase in the early Galaxy. In the present study, we show that given the range of metallicities observed in the bulge, a uniformly old population would be reflected into a significant spread in color at the turn-off which is not observed. Inversely, we demonstrate that the correlation between age and metallicity expected to hold for the inner disk would conspire to form a color-magnitude diagram with a remarkably small spread in color, thus mimicking the color-magnitude diagram of a uniformly old population. If stars younger than 10 Gyr are part of the bulge, as must be the case if the bulge has been mainly formed through dynamical instabilities in the disk, then a very small spread at the turn-off is expected, as seen in the observations., Comment: 11 pages, 11 figures. Accepted for publication in A&A
Published: 2016
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45. A new look at the kinematics of the bulge from an N-body model

Author: Gomez, A., Di Matteo, P., Stefanovitch, N., Haywood, M., Combes, F., Katz, D., and Babusiaux, C.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: (Abridged) By using an N-body simulation of a bulge that was formed via a bar instability mechanism, we analyse the imprints of the initial (i.e. before bar formation) location of stars on the bulge kinematics, in particular on the heliocentric radial velocity distribution of bulge stars. Four different latitudes were considered: $b=-4^\circ$, $-6^\circ$, $-8^\circ$, and $-10^\circ$, along the bulge minor axis as well as outside it, at $l=\pm5^\circ$ and $l=\pm10^\circ$. The bulge X-shaped structure comprises stars that formed in the disk at different locations. Stars formed in the outer disk, beyond the end of the bar, which are part of the boxy peanut-bulge structure may show peaks in the velocity distributions at positive and negative heliocentric radial velocities with high absolute values that can be larger than 100 $\rm km$ $\rm s^{-1}$, depending on the observed direction. In some cases the structure of the velocity field is more complex and several peaks are observed. Stars formed in the inner disk, the most numerous, contribute predominantly to the X-shaped structure and present different kinematic characteristics. Our results may enable us to interpret the cold high-velocity peak observed in the APOGEE commissioning data, as well as the excess of high-velocity stars in the near and far arms of the X-shaped structure at $l$=$0^\circ$ and $b$=$-6^\circ$. When compared with real data, the kinematic picture becomes more complex due to the possible presence in the observed samples of classical bulge and/or thick disk stars. Overall, our results point to the existence of complex patterns and structures in the bulge velocity fields, which are generated by the bar. This suggests that caution should be used when interpreting the bulge kinematics: the presence of substructures, peaks and clumps in the velocity fields is not necessarily a sign of past accretion events., Comment: 21 pages, 18 figures. Accepted for publication in A&A
Published: 2016
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46. When the Milky Way turned off the lights: APOGEE provides evidence of star formation quenching in our Galaxy

Author: Haywood, M., Lehnert, M. D., Di Matteo, P., Snaith, O., Schultheis, M., Katz, D., and Gomez, A.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Quenching, the cessation of star formation, is one of the most significant events in the life cycle of galaxies. We show here the first evidence that the Milky Way experienced a generalised quenching of its star formation at the end of its thick disk formation $\sim$9 Gyr ago. Elemental abundances of stars studied as part of the APOGEE survey reveal indeed that in less than $\sim$2 Gyr the star formation rate in our Galaxy dropped by an order-of-magnitude. Because of the tight correlation between age and alpha abundance, this event reflects in the dearth of stars along the inner disk sequence in the [Fe/H]-[$\alpha$/Fe] plane. Before this phase, which lasted about 1.5 Gyr, the Milky Way was actively forming stars. Afterwards, the star formation resumed at a much lower level to form the thin disk. These events are very well matched by the latest observation of MW-type progenitors at high redshifts. In late type galaxies, quenching is believed to be related to a long and secular exhaustion of gas. In our Galaxy, it occurred on a much shorter time scale, while the chemical continuity before and after the quenching indicates that it was not due to the exhaustion of the gas. While quenching is generally associated with spheroids, our results show that it also occurs in galaxies like the Milky Way, possibly when they are undergoing a morphological transition from thick to thin disks. Given the demographics of late type galaxies in the local universe, in which classical bulges are rare, we suggest further that this may hold true generally in galaxies with mass lower than or approximately $M^*$, where quenching could be directly a consequence of thick disk formation. We emphasize that the quenching phase in the Milky Way could be contemporaneous with, and related to, the formation of the bar. We sketch a scenario on how a strong bar may inhibit star formation., Comment: 17 pages, 8 figures. Published version
Published: 2016
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47. Clues to the formation of the Milky Way's thick disk

Author: Haywood, M., Di Matteo, P., Snaith, O., and Lehnert, M.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We analyse the chemical properties of a set of solar vicinity stars, and show that the small dispersion in abundances of \alpha-elements at all ages provides evidence that the SFH has been uniform throughout the thick disk. In the context of long time scale infall models, we suggest that this result points either to a limited dependence of the gas accretion on the Galactic radius in the inner disk (R<10 kpc), or to a decoupling of the accretion history and star formation history due to other processes governing the ISM in the early disk, suggesting that infall cannot be a determining parameter of the chemical evolution at these epochs. We argue however that these results and other recent observational constraints -- namely the lack of radial metallicity gradient and the non-evolving scale length of the thick disk -- are better explained if the early disk is viewed as a pre-assembled gaseous system, with most of the gas settled before significant star formation took place -- formally the equivalent of a closed-box model. In any case, these results point to a weak, or non-existent inside-out formation history in the thick disk, or in the first 3-5 Gyr of the formation of the Galaxy. We argue however that the growing importance of an external disk whose chemical properties are distinct from those of the inner disk would give the impression of an inside-out growth process when seen through snapshots at different epochs. However, the progressive, continuous process usually invoked may not have actually existed in the Milky Way., Comment: 7 pages, 6 figures, accepted for publication in A&A, replaced to include a correction on the color bar of figure 2 and 3
Published: 2015

48. On the cosmic evolution of the specific star formation rate

Author: Lehnert, M. D., van Driel, W., Tiran, L. Le, Di Matteo, P., and Haywood, M.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The apparent correlation between the specific star formation rate (sSFR) and total stellar mass (M_star) of galaxies is a fundamental relationship indicating how they formed their stellar populations. To attempt to understand this relation, we hypothesize that the relation and its evolution is regulated by the increase in the stellar and gas mass surface density in galaxies with redshift, which is itself governed by the angular momentum of the accreted gas, the amount of available gas, and by self-regulation of star formation. With our model, we can reproduce the specific SFR-M_star relations at z~1-2 by assuming gas fractions and gas mass surface densities similar to those observed for z=1-2 galaxies. We further argue that it is the increasing angular momentum with cosmic time that causes a decrease in the surface density of accreted gas. The gas mass surface densities in galaxies are controlled by the centrifugal support (i.e., angular momentum), and the sSFR is predicted to increase as, sSFR(z)=(1+z)^3/t_H0, as observed (where t_H0 is the Hubble time and no free parameters are necessary). At z>~2, we argue that star formation is self-regulated by high pressures generated by the intense star formation itself. The star formation intensity must be high enough to either balance the hydrostatic pressure (a rather extreme assumption) or to generate high turbulent pressure in the molecular medium which maintains galaxies near the line of instability (i.e. Toomre Q~1). The most important factor is the increase in stellar and gas mass surface density with redshift, which allows distant galaxies to maintain high levels of sSFR. Without a strong feedback from massive stars, such galaxies would likely reach very high sSFR levels, have high star formation efficiencies, and because strong feedback drives outflows, ultimately have an excess of stellar baryons (abridged)., Comment: A&A accepted, 13 pages
Published: 2015
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49. Quantifying stellar radial migration in an N-body simulation: blurring, churning, and the outer regions of galaxy discs

Author: Halle, A., Di Matteo, P., Haywood, M., and Combes, F.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Radial stellar migration in galactic discs has received much attention in studies of galactic dynamics and chemical evolution, but remains a dynamical phenomenon that needs to be fully quantified. In this work, using a Tree-SPH simulation of an Sb-type disc galaxy, we quantify the effects of blurring (epicyclic excursions) and churning (change of guiding radius). We quantify migration (either blurring or churning) both in terms of flux (the number of migrators passing at a given radius), and by estimating the population of migrators at a given radius at the end of the simulation compared to non-migrators, but also by giving the distance over which the migration is effective at all radii. We confirm that the corotation of the bar is the main source of migrators by churning in a bar-dominated galaxy, its intensity being directly linked to the episode of a strong bar, in the first 1-3 Gyr of the simulation. We show that within the outer Lindblad resonance (OLR), migration is strongly dominated by churning, while blurring gains progressively more importance towards the outer disc and at later times. Most importantly, we show that the OLR limits the exchange of angular momentum, separating the disc in two distinct parts with minimal or null exchange, except in the transition zone, which is delimited by the position of the OLR at the epoch of the formation of the bar, and at the final epoch. We discuss the consequences of these findings for our understanding of the structure of the Milky Way disc. Because the Sun is situated slightly outside the OLR, we suggest that the solar vicinity may have experienced very limited churning from the inner disc., Comment: Accepted for publication in Astronomy and Astrophysics (acceptance date: 27/04/15), 24 pages, 24 figures
Published: 2015
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50. Building a Culture of Business Analytics: A Marketing Analytics Exercise

Author: Haywood, M. Elizabeth and Mishra, Anubha
Abstract: Purpose: The purpose of this paper is to describe how brief exercises in introductory and advanced marketing courses can help business students achieve a broader understanding of what Big data and data analytics mean in the workplace. These short analytics problems fit into the culture that we are building at our institution to create analytics cases for courses within our business curriculum. Design/methodology/approach: A database of 1,500 customer reviews for a fictitious sporting company was created. Two exercises based on text mining and sentiment analysis were developed to be tested in introductory and advanced marketing course. Students were introduced to the basic concepts used in data analysis and the creation of R code for extracting sentiment words was demonstrated. Students then used pivot tables to identify patterns in the given data set. Students in the introductory course completed a short exercise while the students in the advanced class developed a detailed memo. Findings: Results suggest that students in the introductory course are significantly more aware of the use of data in the industry as well as methods to deal with Big data after completing the exercise as compared to their knowledge at the beginning of the exercise. Students in the advanced course are able to identify patterns, detect shortcoming and propose strategic plans based on their analysis of the data. Originality/value: Proposed exercises in the study are developed with an aim to help business schools develop a culture supportive of analytics. The purpose of these exercises is to make students aware of the importance of Big data and analytics early on in their curriculum and reinforce their exposure in an advanced course.
Published: 2019
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