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835 results on '"Barstow, M. A."'

202. The photospheric temperatures and composition of very hot He-rich white dwarfs

Author

Barstow, M. A and Holberg, J. B

Subjects
Astrophysics
Abstract

Results are reported from a detailed analysis of Exosat observations of six hot He-rich white dwarfs belonging to, or related to, the spectroscopic subclass of PG1159 stars. These objects are thought to evolve directly from O VI type planetary nebulae nuclei and provide an important link in models of white dwarf evolution. When the Exosat data are compared with the predictions of an extensive grid of He-rich model atmospheres, it is possible to obtain temperature estimates for these stars that are much better constrained than previous attempts.

Published
1990

203. Gaia Data Release 2

Author

Evans, D. W., primary, Riello, M., additional, De Angeli, F., additional, Carrasco, J. M., additional, Montegriffo, P., additional, Fabricius, C., additional, Jordi, C., additional, Palaversa, L., additional, Diener, C., additional, Busso, G., additional, Cacciari, C., additional, van Leeuwen, F., additional, Burgess, P. W., additional, Davidson, M., additional, Harrison, D. L., additional, Hodgkin, S. T., additional, Pancino, E., additional, Richards, P. J., additional, Altavilla, G., additional, Balaguer-Núñez, L., additional, Barstow, M. A., additional, Bellazzini, M., additional, Brown, A. G. A., additional, Castellani, M., additional, Cocozza, G., additional, De Luise, F., additional, Delgado, A., additional, Ducourant, C., additional, Galleti, S., additional, Gilmore, G., additional, Giuffrida, G., additional, Holl, B., additional, Kewley, A., additional, Koposov, S. E., additional, Marinoni, S., additional, Marrese, P. M., additional, Osborne, P. J., additional, Piersimoni, A., additional, Portell, J., additional, Pulone, L., additional, Ragaini, S., additional, Sanna, N., additional, Terrett, D., additional, Walton, N. A., additional, Wevers, T., additional, and Wyrzykowski, Ł., additional

Published
2018
Full Text
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205. Gaia Data Release 1:The photometric data

Author

van Leeuwen, F., Evans, D. W., De Angeli, F., Jordi, C., Busso, G., Cacciari, C., Riello, M., Pancino, E., Altavilla, G., Brown, A. G. A., Burgess, P., Carrasco, J. M., Cocozza, G., Richards, P. J., Rowell, N., Castellani, M., Delgado, A., Hog, E., van Leeuwen, M., Millar, N. R., Pagani, C., Piersimoni, A. M., Pulone, L., Rixon, G., Suess, F. F., Alecu, A., Allan, P. M., Balaguer-Nunez, L., Barstow, M. A., Bellazzini, M., Belokurov, V., Blagorodnova, N., Bonfigli, M., Bragaglia, A., Brown, S., Bunclark, P., Buonanno, R., Burgon, R., Campbell, H., Collins, R. S., Cross, N. J. G., Ducourant, C., van Elteren, A., Evans, N. W., Federici, L., Fernandez-Hernandez, J., Figueras, F., Fraser, M., Fyfe, D., Gebran, M., Torra, J., Trager, S. C., Troisi, L., Valentini, G., Vallenari, A., Wevers, T., van Leeuwen, F., Evans, D. W., De Angeli, F., Jordi, C., Busso, G., Cacciari, C., Riello, M., Pancino, E., Altavilla, G., Brown, A. G. A., Burgess, P., Carrasco, J. M., Cocozza, G., Richards, P. J., Rowell, N., Castellani, M., Delgado, A., Hog, E., van Leeuwen, M., Millar, N. R., Pagani, C., Piersimoni, A. M., Pulone, L., Rixon, G., Suess, F. F., Alecu, A., Allan, P. M., Balaguer-Nunez, L., Barstow, M. A., Bellazzini, M., Belokurov, V., Blagorodnova, N., Bonfigli, M., Bragaglia, A., Brown, S., Bunclark, P., Buonanno, R., Burgon, R., Campbell, H., Collins, R. S., Cross, N. J. G., Ducourant, C., van Elteren, A., Evans, N. W., Federici, L., Fernandez-Hernandez, J., Figueras, F., Fraser, M., Fyfe, D., Gebran, M., Torra, J., Trager, S. C., Troisi, L., Valentini, G., Vallenari, A., and Wevers, T.

Published
2017

211. Gaia Data Release 1

Author

Brown, A., Vallenari, A., Prusti, T., de Bruijne, J. H.J., Mignard, F., Drimmel, R., Babusiaux, C., Bailer-Jones, C. A.L., Bastian, U., Biermann, M., Evans, D., Eyer, L., Jansen, F., Jordi, C., Katz, D., Klioner, S., Lammers, U., Lindegren, L., Luri, X., O’mullane, W., Panem, C., Pourbaix, D., Randich, S., Sartoretti, P., Siddiqui, H., Soubiran, C., Valette, V., van Leeuwen, F., Walton, N., Aerts, C., Arenou, F., Cropper, M., Høg, E., Lattanzi, M., Grebel, E., Holland, A., 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., Riello, M., Seabroke, G., Tanga, P., Thévenin, F., Torra, J., Els, S., Gracia-Abril, G., Comoretto, G., Garcia-Reinaldos, M., Lock, T., Mercier, E., Altmann, M., Andrae, R., Astraatmadja, T., 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., Harrison, D., Hauser, M., Hestroffer, D., Hodgkin, S., Huckle, H., Hutton, A., Jasniewicz, G., Jordan, S., Kontizas, M., Korn, A., Lanzafame, A., Manteiga, M., Moitinho, A., Muinonen, K., Osinde, J., Pancino, E., Pauwels, T., Petit, Jean-Marc, Recio-Blanco, A., Robin, Annie C., Sarro, L., Siopis, C., Smith, M., Smith, K., Sozzetti, A., Thuillot, W., van Reeven, W., Viala, Y., Abbas, U., Abreu Aramburu, A., Accart, S., Aguado, J., Allan, P., Allasia, W., Altavilla, G., Álvarez, M., Alves, J., Anderson, R., Andrei, A., Anglada Varela, E., Antiche, E., Antoja, T., Antón, S., Arcay, B., Bach, N., Baker, S., Balaguer-Núñez, L., Barache, C., Barata, C., Barbier, A., Barblan, F., Barrado y Navascués, D., Barros, M., Barstow, M., Becciani, U., Bellazzini, M., Bello García, A., 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., 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., Castellani, M., Charlot, P., Charnas, J., Chiavassa, A., Clotet, M., Cocozza, G., Collins, R., 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., Di Matteo, P., Diakite, S., Distefano, E., Dolding, C., dos Anjos, S., Drazinos, P., Duran, J., Dzigan, Y., Edvardsson, B., Enke, H., Evans, N., Eynard Bontemps, G., Fabre, C., Fabrizio, M., Faigler, S., Falcão, A., Farràs Casas, M., 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., Granvik, M., Guerrier, A., Guillout, P., Guiraud, J., Gúrpide, A., Gutiérrez-Sánchez, R., Guy, L., 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., Jevardat de Fombelle, G., Jofré, P., Jonker, P., Jorissen, A., Julbe, F., Karampelas, A., Kochoska, A., Kohley, R., Kolenberg, K., Kontizas, E., Koposov, S., Kordopatis, G., Koubsky, P., Krone-Martins, A., Kudryashova, M., Kull, I., Bachchan, R., Lacoste-Seris, F., Lanza, A., Lavigne, J.-B., Le Poncin-Lafitte, C., Lebreton, Y., Lebzelter, T., Leccia, S., Leclerc, N., Lecoeur-Taibi, I., Lemaitre, V., Lenhardt, H., Leroux, F., Liao, S., Licata, E., Lindstrøm, H. E.P., Lister, T., Livanou, E., Lobel, A., Löffler, W., López, M., Lorenz, D., Macdonald, I., Magalhães Fernandes, T., Managau, S., Mann, R., Mantelet, G., Marchal, O., Marchant, J., Marconi, M., Marinoni, S., Marrese, P., Marschalkó, G., Marshall, D., Martín-Fleitas, J., Martino, M., Mary, N., Matijevič, G., Mazeh, T., Mcmillan, P., Messina, S., Michalik, D., Millar, N., Miranda, B., Molina, D., Molinaro, R., Molinaro, M., Molnár, L., Moniez, M., Montegriffo, P., Mor, R., Mora, A., Morbidelli, R., Morel, T., Morgenthaler, S., Morris, D., Mulone, A., 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., 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., Rimoldini, L., Ripepi, V., Riva, A., Rixon, G., Roelens, M., Romero-Gómez, M., Rowell, N., Royer, F., Ruiz-Dern, L., Sadowski, G., Sagristà Sellés, T., Sahlmann, J., Salgado, J., Salguero, E., Sarasso, M., Savietto, H., Schultheis, M., Sciacca, E., Segol, M., Segovia, J., Segransan, D., Shih, I.-C., Smareglia, R., Smart, R., Solano, E., Solitro, F., Sordo, R., Soria Nieto, S., Souchay, J., Spagna, A., Spoto, F., Stampa, U., Steele, I., Steidelmüller, H., Stephenson, C., Stoev, H., Suess, F., Süveges, M., Surdej, J., Szabados, L., Szegedi-Elek, E., Tapiador, D., Taris, F., Tauran, G., Taylor, M., Teixeira, R., Terrett, D., Tingley, B., Trager, S., 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., Allende Prieto, C., 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., Carret, C., Carrion, C., Chemin, L., Chéreau, F., Corcione, L., Darmigny, E., de Boer, K., de Teodoro, P., de Zeeuw, P., Delle Luche, C., Domingues, C., 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., Isasi Parache, Y., 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., Marseille, M., Martayan, C., Martinez-Rubi, O., Massart, B., Meynadier, F., Mignot, S., Munari, U., Nguyen, A.-T., Nordlander, T., Ocvirk, P., O’flaherty, K., Olias Sanz, A., Ortiz, P., Osorio, J., Oszkiewicz, D., Ouzounis, A., Palmer, M., 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., Risquez, D., Rocca-Volmerange, B., Rosen, S., Ruiz-Fuertes, M., Russo, F., Sembay, S., Serraller Vizcaino, I., 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., Ziaeepour, H., Zschocke, S., Leiden Observatory [Leiden], Universiteit Leiden, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), ESA Scientific Support Office, Agence Spatiale Européenne = European Space Agency (ESA), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Torino (OATo), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Astronomy (MPIA), Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg] = Heidelberg University-Universität Heidelberg [Heidelberg] = Heidelberg University, Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université libre de Bruxelles (ULB), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Thales Services, THALES [France], Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astrophysics Research Institute [Liverpool] (ARI), Liverpool John Moores University (LJMU), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Leicester, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Royal Observatory of Belgium [Brussels] (ROB), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Leibniz Institute for Astrophysics Potsdam (AIP)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016
Full Text
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212. The life of stars and their planets

Author

Catala, C, Aerts, C, Aigrain, S, Antonello, E, Appourchaux, T, Auvergne, M, Baglin, A, Barge, P, Barstow, M, Baudin, F, Boumier, P, Cameron, A, Christensen-Dalsgaard, J, Cutispoto, G, Deeg, H, Deleuil, M, Desidera, S, Donati, J, Favata, F, Foing, B, Gameiro, J, García, R, Garrido, R, Horne, K, and Lanza, A

Abstract

We lack a reliable scenario for the formation and evolution of stars and their planetary systems, involving key factors such as magnetic fields and turbulence. We present the case for a mission concept that will clarify these problems and give us a global view of the evolution of combined star and planetary systems. This will be achieved by simultaneously addressing the search for planetary transits in front of a large number of stars, including many nearby stars, the study of their internal structure and evolution via asteroseismology, and that of their magnetic activity, via UV monitoring.

Published
2016

213. GaiaData Release 1

Author

van Leeuwen, F., primary, Evans, D. W., additional, De Angeli, F., additional, Jordi, C., additional, Busso, G., additional, Cacciari, C., additional, Riello, M., additional, Pancino, E., additional, Altavilla, G., additional, Brown, A. G. A., additional, Burgess, P., additional, Carrasco, J. M., additional, Cocozza, G., additional, Cowell, S., additional, Davidson, M., additional, De Luise, F., additional, Fabricius, C., additional, Galleti, S., additional, Gilmore, G., additional, Giuffrida, G., additional, Hambly, N. C., additional, Harrison, D. L., additional, Hodgkin, S. T., additional, Holland, G., additional, MacDonald, I., additional, Marinoni, S., additional, Montegriffo, P., additional, Osborne, P., additional, Ragaini, S., additional, Richards, P. J., additional, Rowell, N., additional, Voss, H., additional, Walton, N. A., additional, Weiler, M., additional, Castellani, M., additional, Delgado, A., additional, Høg, E., additional, van Leeuwen, M., additional, Millar, N. R., additional, Pagani, C., additional, Piersimoni, A. M., additional, Pulone, L., additional, Rixon, G., additional, Suess, F. F., additional, Wyrzykowski, Ł., additional, Yoldas, A., additional, Alecu, A., additional, Allan, P. M., additional, Balaguer-Núñez, L., additional, Barstow, M. A., additional, Bellazzini, M., additional, Belokurov, V., additional, Blagorodnova, N., additional, Bonfigli, M., additional, Bragaglia, A., additional, Brown, S., additional, Bunclark, P., additional, Buonanno, R., additional, Burgon, R., additional, Campbell, H., additional, Collins, R. S., additional, Cross, N. J. G., additional, Ducourant, C., additional, van Elteren, A., additional, Evans, N. W., additional, Federici, L., additional, Fernández-Hernández, J., additional, Figueras, F., additional, Fraser, M., additional, Fyfe, D., additional, Gebran, M., additional, Heyrovsky, A., additional, Holl, B., additional, Holland, A. D., additional, Iannicola, G., additional, Irwin, M., additional, Koposov, S. E., additional, Krone-Martins, A., additional, Mann, R. G., additional, Marrese, P. M., additional, Masana, E., additional, Munari, U., additional, Ortiz, P., additional, Ouzounis, A., additional, Peltzer, C., additional, Portell, J., additional, Read, A., additional, Terrett, D., additional, Torra, J., additional, Trager, S. C., additional, Troisi, L., additional, Valentini, G., additional, Vallenari, A., additional, and Wevers, T., additional

Published
2017
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214. A possible solution to the Lyman/Balmer line problem in hot DA white dwarfs

Author

Preval, S. P., Barstow, M. A., Badnell, N. R., Holberg, J. B., Hubeny, I., Dufour, P., Bergeron, P., and Fontaine, G.

Subjects
QB
Abstract

Arguably, the best method for determining the effective temperature (T[subscript: eff]) and surface gravity (log g) of a DA white dwarf is by fitting the Hydrogen Lyman and Balmer absorption features. However, as has been shown for white dwarfs with T[subscript: eff]>50,000K, the calculated value from the Lyman and Balmer lines are discrepant, which worsens with increasing temperature. Many different solutions have been suggested, ranging from the input physics used to calculate the models, to interstellar reddening. We will focus on the former, and consider three variables. The first is the atomic data used, namely the number of transitions included in line blanketing treatments and the photoionization cross sections. The second is the stark broadening treatment used to synthesise the Lyman and Balmer line profiles, namely the calculations performed by Lemke (1997) and Tremblay & Bergeron (2009). Finally, the third is the atmospheric content. The model grids are calculated with a pure H composition, and a metal polluted composition using the abundances of Preval et al. (2013). We present the preliminary results of our analysis, whereby we have determined the T[subscript: eff] for a small selection of white dwarfs. We plan to extend our analysis by allowing metallicity to vary in future model grids.

Published
2015

215. Do the constants of nature couple to strong gravitational fields?

Author

Preval, S. P., Barstow, M. A., Holberg, J. B., Barrow, J. D., Berengut, J. C., Webb, J. K., Dougan, D., Hu, J., Dufour, P., Bergeron, P., and Fontaine, G.

Subjects
QB
Abstract

Recently, white dwarf stars have found a new use in the fundamental physics community. Many prospective theories of the fundamental interactions of Nature allow traditional constants, like the fine structure constant α, to vary in some way. A study by Berengut et al. (2013) used the Fe/Ni v line measurements made by Preval et al. (2013) from the hot DA white dwarf G191-B2B, in an attempt to detect any variation in α. It was found that the Fe v lines indicated an increasing alpha, whereas the Ni v lines indicated a decreasing alpha. Possible explanations for this could be misidenti- fication of the lines, inaccurate atomic data, or wavelength dependent distortion in the spectrum. We examine the first two cases by using a high S/N reference spectrum from the hot sdO BD+28◦4211 to calibrate the Fe/Ni v atomic data. With this new data, we re-evaluate the work of Berengut et al. (2013) to derive a new constraint on the variation of alpha in a gravitational field.

Published
2015

216. Gaia Data Release 1 Summary of the astrometric, photometric, and survey properties

Author

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

Abstract

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

Published
2016
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217. The Gaia mission

Author

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

Abstract

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

Published
2016
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218. Stellar Archaeology with Gaia: The Galactic White Dwarf Population

Author

Skillen, I., Gänsicke, B., Tremblay, P., Barstow, M., Bono, G., Burleigh, M., Casewell, S., Dhillon, V., Farihi, J., Garcia-Berro, E., Geier, S., Gentile-Fusillo, N., Hermes, J., Hollands, M., Istrate, A., Knigge, C., Manser, C., Marsh, T., Nelemans, G.A., Pala, A., Raddi, R., Tauris, T., Toloza, O., Veras, D., Werner, K., Barcells, M., Trager, S., Skillen, I., Gänsicke, B., Tremblay, P., Barstow, M., Bono, G., Burleigh, M., Casewell, S., Dhillon, V., Farihi, J., Garcia-Berro, E., Geier, S., Gentile-Fusillo, N., Hermes, J., Hollands, M., Istrate, A., Knigge, C., Manser, C., Marsh, T., Nelemans, G.A., Pala, A., Raddi, R., Tauris, T., Toloza, O., Veras, D., Werner, K., Barcells, M., and Trager, S.

Abstract

Multi-Object Spectroscopy in the Next Decade: Big Questions, Large Surveys, and Wide Fields, Teatro Circo de Marte, Santa Cruz de La Palma Canary Islands, Spain 2–6 March 2015, Contains fulltext : 166023.pdf (publisher's version ) (Closed access)

Published
2016

219. Gaia data release 1, the photometric data

Author

van Leeuwen, F., Evans, D. W., De Angeli, F., Jordi, C., Busso, G., Cacciari, C., Riello, M., Pancino, E., Altavilla, G., Brown, A. G. A., Burgess, P., Carrasco, J. M., Cocozza, G., Cowell, S., Davidson, M., De Luise, F., Fabricius, C., Galleti, S., Gilmore, G., Giuffrida, G., Hambly, N. C., Harrison, D. L., Hodgkin, S. T., Holland, G., MacDonald, I., Marinoni, S., Montegrffo, P., Osborne, P., Ragaini, S., Richards, P. J., Rowell, N., Voss, H., Walton, N. A., Weiler, M., Castellani, M., Delgado, A., Høg, E., van Leeuwen, M., Millar, N. R., Pagani, C., Piersimoni, A. M., Pulone, L., Rixon, G., Suess, F. F., Wyrzykowski, Ł., Yoldas, A., Alecu, A., Allan, P. M., Balaguer-Núñez, L., Barstow, M. A., Bellazzini, M., Belokurov, V., Blagorodnova, N., Bonfigli, M., Bragaglia, A., Brown, S., Bunclark, P., Buonanno, R., Burgon, R., Campbell, H., Collins, R. S., Cross, N. J. G., Ducourant, C., van Elteren, A., Evans, N. W., Federici, L., Fernández-Hernández, J., Figueras, F., Fraser, M., Fyfe, D., Gebran, M., Heyrovsky, A., Holl, B., Holland, A. D., Iannicola, G., Irwin, M., Koposov, S. E., Krone-Martins, A., Mann, R. G., Marrese, P. M., Masana, E., Munari, U., Ortiz, P., Ouzounis, A., Peltzer, C., Portell, J., Read, A., Terrett, D., Torra, J., Trager, S. C., Troisi, L., Valentini, G., Vallenari, A., Wevers, T., van Leeuwen, F., Evans, D. W., De Angeli, F., Jordi, C., Busso, G., Cacciari, C., Riello, M., Pancino, E., Altavilla, G., Brown, A. G. A., Burgess, P., Carrasco, J. M., Cocozza, G., Cowell, S., Davidson, M., De Luise, F., Fabricius, C., Galleti, S., Gilmore, G., Giuffrida, G., Hambly, N. C., Harrison, D. L., Hodgkin, S. T., Holland, G., MacDonald, I., Marinoni, S., Montegrffo, P., Osborne, P., Ragaini, S., Richards, P. J., Rowell, N., Voss, H., Walton, N. A., Weiler, M., Castellani, M., Delgado, A., Høg, E., van Leeuwen, M., Millar, N. R., Pagani, C., Piersimoni, A. M., Pulone, L., Rixon, G., Suess, F. F., Wyrzykowski, Ł., Yoldas, A., Alecu, A., Allan, P. M., Balaguer-Núñez, L., Barstow, M. A., Bellazzini, M., Belokurov, V., Blagorodnova, N., Bonfigli, M., Bragaglia, A., Brown, S., Bunclark, P., Buonanno, R., Burgon, R., Campbell, H., Collins, R. S., Cross, N. J. G., Ducourant, C., van Elteren, A., Evans, N. W., Federici, L., Fernández-Hernández, J., Figueras, F., Fraser, M., Fyfe, D., Gebran, M., Heyrovsky, A., Holl, B., Holland, A. D., Iannicola, G., Irwin, M., Koposov, S. E., Krone-Martins, A., Mann, R. G., Marrese, P. M., Masana, E., Munari, U., Ortiz, P., Ouzounis, A., Peltzer, C., Portell, J., Read, A., Terrett, D., Torra, J., Trager, S. C., Troisi, L., Valentini, G., Vallenari, A., and Wevers, T.

Abstract

Context. This paper presents an overview of the photometric data that are part of the first Gaia data release. Aims. The principles of the processing and the main characteristics of the Gaia photometric data are presented. Methods. The calibration strategy is outlined briefly and the main properties of the resulting photometry are presented. Results. Relations with other broadband photometric systems are provided. The overall precision for the Gaia photometry is shown to be at the milli-magnitude level and has a clear potential to improve further in future releases., Comment: 9 pages, 6 figures, 1 table, Accepted for publication by A&A as part of the Gaia 1st data release issue

Published
2016
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220. Understanding the spectrum of the very hot DA white dwarf PG0948+534

Author

Preval, S. P., Barstow, M. A., Preval, S. P., and Barstow, M. A.

Abstract

PG0948+534 is currently one of the hottest DA white dwarf stars, and is also one of the most mysterious. Attempts to model the sharp, deep absorption features of this star have been unsuccessful. In these proceedings we describe our analysis of PG0948+534. We perform a line survey of the UV spectrum of PG0948+534, making detections of 300+ absorption features, and identifying four distinct velocity regimes. We find evidence of circumstellar absorption in the profiles of C {\sc iv} and Si {\sc iv}. Using non-local thermodynamic equilibrium model atmospheres, we are able to correctly model the absorption features of the star, providing abundance measurements for C, N, O, and Si for PG0948+534 for the first time. We also revise the effective temperature and gravity for this star using models including these new abundances., Comment: Six pages, two figures. To appear in the proceedings of the 20th European White Dwarf Workshop held in Warwick, 2016

Published
2016

221. Hot DA white dwarf model atmosphere calculations: Including improved Ni PI cross sections

Author

Preval, S. P., Barstow, M. A., Badnell, N. R., Hubeny, I., Holberg, J. B., Preval, S. P., Barstow, M. A., Badnell, N. R., Hubeny, I., and Holberg, J. B.

Abstract

To calculate realistic models of objects with Ni in their atmospheres, accurate atomic data for the relevant ionization stages needs to be included in model atmosphere calculations. In the context of white dwarf stars, we investigate the effect of changing the Ni {\sc iv}-{\sc vi} bound-bound and bound-free atomic data has on model atmosphere calculations. Models including PICS calculated with {\sc autostructure} show significant flux attenuation of up to $\sim 80$\% shortward of 180\AA\, in the EUV region compared to a model using hydrogenic PICS. Comparatively, models including a larger set of Ni transitions left the EUV, UV, and optical continua unaffected. We use models calculated with permutations of this atomic data to test for potential changes to measured metal abundances of the hot DA white dwarf G191-B2B. Models including {\sc autostructure} PICS were found to change the abundances of N and O by as much as $\sim 22$\% compared to models using hydrogenic PICS, but heavier species were relatively unaffected. Models including {\sc autostructure} PICS caused the abundances of N/O {\sc iv} and {\sc v} to diverge. This is because the increased opacity in the {\sc autostructure} PICS model causes these charge states to form higher in the atmosphere, moreso for N/O {\sc v}. Models using an extended line list caused significant changes to the Ni {\sc iv}-{\sc v} abundances. While both PICS and an extended line list cause changes in both synthetic spectra and measured abundances, the biggest changes are caused by using {\sc autostructure} PICS for Ni., Comment: 14 pages, 9 figures, 7 tables. Accepted for publication in MNRAS

Published
2016
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222. Do the constants of nature couple to strong gravitational fields?

Author

Preval, S. P., Barstow, M. A., Holberg, J. B., Barrow, J. D., Berengut, J. C., Webb, J. K., Dougan, D., and Hu, J.

Subjects
Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), General Relativity and Quantum Cosmology, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Recently, white dwarf stars have found a new use in the fundamental physics community. Many prospective theories of the fundamental interactions of Nature allow traditional constants, like the fine structure constant $\alpha$, to vary in some way. A study by Berengut et al. (2013) used the Fe/Ni V line measurements made by Preval et al. (2013) from the hot DA white dwarf G191-B2B, in an attempt to detect any variation in $\alpha$. It was found that the Fe V lines indicated an increasing alpha, whereas the Ni V lines indicated a decreasing alpha. Possible explanations for this could be misidentification of the lines, inaccurate atomic data, or wavelength dependent distortion in the spectrum. We examine the first two cases by using a high S/N reference spectrum from the hot sdO BD+28$^{\circ}$4211 to calibrate the Fe/Ni V atomic data. With this new data, we re-evaluate the work of Berengut et al. (2013) to derive a new constraint on the variation of alpha in a gravitational field., Comment: 4 pages, 2 figures: To appear in the proceedings of the "19th European White Dwarf Workshop" in Montreal, Canada, 2014

Published
2014
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224. Refining our knowledge of the white dwarf mass-radius relation

Author

Barstow, M. A., Bond, H. E., Burleigh, M. R., Casewell, S. L., Farihi, J., Holberg, J. B., Hubeny, I., Barstow, M. A., Bond, H. E., Burleigh, M. R., Casewell, S. L., Farihi, J., Holberg, J. B., and Hubeny, I.

Abstract

The presence of a white dwarf in a resolved binary system, such as Sirius, provides an opportunity to combine dynamical information about the masses, from astrometry and spectroscopy, with a gravitational red-shift measurement and spectrophotometry of the white dwarf atmosphere to provide a test of theoretical mass-radius relations of unprecedented accuracy. We demonstrated this with the first Balmer line spectrum of Sirius B to be obtained free of contamination from the primary, with STIS on HST. However, we also found an unexplained discrepancy between the spectroscopic and gravitational red-shift mass determinations. With the recovery of STIS, we have been able to revisit our observations of Sirius B with an improved observation strategy designed to reduce systematic errors on the gravitational red-shift measurement. We provide a preliminary report on the refined precision of the Sirius B mass-radius measurements and the extension of this technique to a larger sample of white dwarfs in resolved binaries. Together these data can provide accurate mass and radius determinations capable of testing the theoretical mass-radius relation and distinguishing between possible structural models., Comment: To be published in the proceedings of the 19th European White Dwarf Workshop, Montreal, 2014

Published
2015

230. The World Space Observatory Project WSO/UV

Author

Pagano I, Rodono M, Bonanno G, Buson L, Cassatella A, De Martino D, Wamsteker W, Shustov B, Barstow M, Brosch N, Cheng Fu Zhen1, Dennefeld M, Gomez de Castro A. I, Kappelmann N, Sahade J, Van der Hucht K, Solheim J. E, Haubold H, ALTAMORE, Aldo, Pagano, I, Rodono, M, Bonanno, G, Buson, L, Cassatella, A, De Martino, D, Wamsteker, W, Shustov, B, Barstow, M, Brosch, N, Cheng Fu, Zhen1, Dennefeld, M, Gomez de Castro A., I, Kappelmann, N, Sahade, J, Van der Hucht, K, Solheim J., E, Haubold, H, and Altamore, Aldo

Subjects
Astrophysics::Instrumentation and Methods for Astrophysics
Abstract

The World Space Observatory Project is a new space mission concept, grown out the needs of the Astronomical community to have access to the part of the electromagnetic spectrum where all known physics can be studied on all possible time scales: the Ultraviolet range. The physical diagnostics in this domain supply a richness of new experimental data unmatched by any other wavelength range, for the studies of the Universe. As WSO/UV has been driven by the needs of scientists from many different countries, a new implementation model was needed to bring theWorld Space Observatory to reality. The WSO/UV consists of a single Ultraviolet Telescope in orbit, incorporating a primary mirror of 1.7 m diameter feeding a UV spectrograph and UV Imagers.

Published
2003

232. Towards a standardized line list for G 191-B2B and other DA type objects

Author

Preval, S. P., Barstow, M. A., Holberg, J. B., Dickinson, N. J., Krzesinski, Jurek, Stachowski, Greg, Moskalik, Paweł, and Bajan, Katarzyna

Subjects
QB
Abstract

We present a comprehensive analysis of the far UV spectrum of G 191-B2B over the range of 900–1700Å using co-added data from the FUSE and STIS archives. While previous identifications made by Holberg et al. (2003) are reaffirmed in this work, it is found that many previously unidentified lines can now be attributed to Fe, Ni, and a few lighter metals. Future work includes extending this detailed analysis to a wider range of DA objects, in the expectation that a more complete analysis of their atmospheres can be realised.

Published
2013

233. Testing the white dwarf mass–radius relation and comparing optical and far-UV spectroscopic results with <italic>Gaia</italic> DR2, <italic>HST</italic>, and <italic>FUSE</italic>.

Author

Joyce, S R G, Barstow, M A, Casewell, S L, Burleigh, M R, Holberg, J B, and Bond, H E

Subjects
*ASTRONOMICAL observations, *WHITE dwarf stars, *STELLAR mass, *STELLAR spectra, *ULTRAVIOLET spectroscopy, *BINARY stars
Abstract

Observational tests of the white dwarf mass–radius relationship have always been limited by the uncertainty in the available distance measurements. Most studies have focused on Balmer line spectroscopy because these spectra can be obtained from ground-based observatories, while the Lyman lines are only accessible to space-based UV telescopes. We present results using parallax data from Gaia DR2 combined with space-based spectroscopy from HST and FUSE covering the Balmer and Lyman lines. We find that our sample supports the theoretical relation, although there is at least one star which is shown to be inconsistent. Comparison of results between Balmer and Lyman line spectra shows they are in agreement when the latest broadening tables are used. We also assess the factors which contribute to the error in the mass–radius calculations and confirm the findings of other studies which show that the spread in results for targets where multiple spectra are available is larger than the statistical error. The uncertainty in the spectroscopically derived log g parameter is now the main source of error rather than the parallax. Finally, we present new results for the radius and spectroscopic mass of Sirius B which agree with the dynamical mass and mass–radius relation within 1σ. [ABSTRACT FROM AUTHOR]

Published
2018
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234. The distribution of metals in hot DA white dwarfs

Author

Dickinson, N. J., Barstow, M. A., and Hubeny, I.

Subjects
Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

The importance to stellar evolution of understanding the metal abundances in hot white dwarfs is well known. Previous work has found the hot DA white dwarfs REJ 1032+532, REJ 1614-085 and GD 659 to have highly abundant, stratified photospheric nitrogen, due to the narrow absorption line profiles of the FUV N V doublet and the lack of EUV continuum absorption. A preliminary analysis of the extremely narrow, deep line profiles of the photospheric metal absorption features of PG 0948+534 suggested a similar photospheric metal configuration. However, other studies have found REJ 1032+532, REJ 1614-085 and GD 659 can be well described by homogeneous models, with nitrogen abundances more in keeping with those of white dwarfs with higher effective temperatures. Here, a re-analysis of the nitrogen absorption features seen in REJ 1032+532, REJ 1614-085 and GD 659 is presented, with the aim of better understanding the structure of these stars, to test which models better represent the observed data and apply the results to the line profiles seen in PG 0948+534. A degeneracy is seen in the modelling of the nitrogen absorption line profiles of REJ 1032+532, REJ 1614-085 and GD 659, with low abundance, homogeneously distributed nitrogen models most likely being a better representation of the observed data. In PG 0948+534, no such degeneracy is seen, and the enigmatically deep line profiles could not be modelled satisfactorially., 7 pages, 14 figures, accepted for publication in MNRAS

Published
2012

235. The origin of circumstellar features in the spectra of hot DA white dwarfs

Author

Dickinson, N. J., Barstow, M. A., Welsh, B. Y., Burleigh, M., Farihi, J., Redfield, S., and Unglaub, K.

Subjects
Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

We have analysed a sample of 23 hot DAs to better understand the source of the circumstellar features reported in previous work. Unambiguous detections of circumstellar material are again made at eight stars. The velocities of the circumstellar material at three of the white dwarfs are coincident with the radial velocities of ISM along the sight line to the stars, suggesting that the objects may be ionising the ISM in their locality. In three further cases, the circumstellar velocities are close to the ISM velocities, indicating that these objects are either ionising the ISM, or evaporated planetesimals/material in a circumstellar disc. The circumstellar velocity at WD 1614-084 lies far from the ISM velocities, indicating either the ionisation of an undetected ISM component or circumstellar material. The material seen at WD 0232+035 can be attributed to the photoionisation of material lost from its M dwarf companion. The measured column densities of the circumstellar material lie within the ionised ISM column density ranges predicted to exist in hot DA Stromgren spheres., Comment: 15 pages, 7 figures, accepted for publication in MNRAS

Published
2012
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236. On the Origin of Metals in Some Hot White Dwarf Photospheres

Author

Burleigh, M. R., Barstow, M. A., Farihi, J., Bannister, N. P., Dickinson, N., Steele, P. R., Dobbie, P. D., Faedi, F., and G��nsicke, B. T.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

We have searched for evidence for dust and gas disks at a sample of hot DA white dwarfs 20 000K < Teff < 50 000K, without success. Although their atmospheres are polluted with heavy elements, we cannot yet convincingly and conclusively show that any of these objects is accreting metals from surrounding material derived from disrupted minor planets in an old solar system., Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.6606

Published
2011

237. White dwarfs in the UKIDSS Large Area Survey: The Substellar Companion Fraction

Author

Steele, P. R., Burleigh, M. R., Dobbie, P. D., Jameson, R. F., Barstow, M. A., and Satterthwaite, R. P.

Subjects
Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

We present a near-infrared photometric search for unresolved substellar companions and debris disks around white dwarfs in the UKIRT Infrared Deep Sky Survey Large Area Survey. We cross-correlate the SDSS DR4 and McCook & Sion catalogues of white dwarfs with the UKIDSS DR8 producing 3109 and 163 unique matches respectively. Cooling models are fitted to the optical photometry of a subsample of DA white dwarfs and extended to the near-infrared. A comparison is then made with the observed photometry to identify those stars with a near-infrared excess consistent with the presence of a cool companion or debris disk. Where present, we have estimated the approximate spectral type of any putative companion, or an upper limit on the temperature of a debris disk. In total we identify 14-16 new candidate white dwarf + very low mass stellar systems, 9-11 candidate white dwarf + brown dwarf systems, and 3 candidate white dwarf + debris disks. We place lower limits on the unresolved (0.4+/-0.3%, f(WD+dT)>0.2% and f(WD+BD)>0.5+/-0.3%., 26 pages, 17 figures (+ 30 appendix figures), 10 tables. Accepted MNRAS June 10th 2011

Published
2011
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238. Evolutionary Constraints on the Planet-Hosting Subgiant Epsilon Reticulum from its White Dwarf Companion

Author

Farihi, J., Burleigh, M. R., Holberg, J. B., Casewell, S. L., and Barstow, M. A.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

The planet-hosting and Sirius-type binary system epsilon Reticulum (HD 27442) is examined from the perspective of its more evolved white dwarf secondary. The stellar parameters are determined from a combination of Balmer line spectroscopy, gravitational redshift, and solid angle. These three methods conspire to yield the most accurate physical description of the companion to date: Teff=15,310 \pm 350 K and M=0.60 \pm 0.02 Msol. Post-main sequence mass loss indicates the current binary separation has increased by a factor of 1.6 from its primordial state when the current primary was forming its planet(s), implying a0 > 150 AU and constraining stable planets to within 15-20 AU for a binary eccentricity of e=0.5. Almost 80 years have passed since the first detection of the stellar companion, and marginal orbital motion may be apparent in the binary, suggesting a near edge-on configuration with i > 70 deg, albeit with substantial uncertainty. If correct, and all known bodies are coplanar, the mass of the planet HD 27442b is bound between 1.66 and 1.77 Mjup. A search for photospheric metals in the DA white dwarf yields no detections, and hence there is no clear signature of an extant planetary system orbiting the previously more massive secondary. However, if the white dwarf mass derived via spectral fitting is correct, its evolution could have been influenced by interactions with inner planets during the asymptotic giant branch. Based on the frequency of giant planets and circumstellar debris as a function of stellar mass, it is unlikely that the primordial primary would be void of planets, given at least one orbiting its less massive sibling., 9 pages, 5 figures, 3 tables; accepted to MNRAS

Published
2011
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239. The pulsations of PG 1351+489

Author

Claver, C. F., Chernyshev, A. V., Wood, M. A., Giovannini, O., Hansen, C. J., Leibowitz, E., Handler, G., Sullivan, D. J., Rosen, R., Nagel, T., Chen, W.-P., Kanaan, A., Buckley, D., Walter, B., Winiarski, M., Ibbetson, P., Zhang, X., Redaelli, M., Chandler, D., Baliyan, K. S., Ogloza, W., Marar, T. M. K., Fraga, L., Brewer, M. M., Andreev, M. V., Winget, D. E., Henrique, P., Strickland, W., Provencal, J. L., Silvotti, R., Chevreton, M., Nather, R. E., Pajdosz, G., Clemens, J. C., Pfeiffer, B., Fremy, J. R., Shih, C.-Y., Costa, J. E. S., Moskalik, P., Hemar, S., Sergeev, A. V., Janulis, R., Kepler, S. O., Kim, S.-L., O'Donoghue, D., Jiang, X., Bognár, Zs, Dolez, N., Vats, H. O., Vauclair, G., Meištas, E. G., Yang, M., Barstow, M. A., Shipman, H. L., Mullally, F., Baran, A., Castanheira, B. G., Childers, D., Brown, T. M., Dalessio, J., Creevey, O. L., Ashoka, B. N., Seetha, S., Oksala, M. E., Bischoff-Kim, A., Thompson, S. E., Kleinman, S. J., Solheim, J.-E., Zola, S., Kawaler, S. D., Montgomery, M. H., Fu, J. N., Reed, M. D., Nitta, A., Bruni, I., Watson, T. K., Sefako, R., and Siwak, M.

Subjects
Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics
Abstract

PG 1351+489 is one of the 20 DBVs – pulsating helium-atmosphere white dwarf stars – known and has the simplest power spectrum for this class of star, making it a good candidate to study cooling rates. We report accurate period determinations for the main peak at 489.334 48 s and two other normal modes using data from the Whole Earth Telescope (WET) observations of 1995 and 2009. In 2009, we detected a new pulsation mode and the main pulsation mode exhibited substantial change in its amplitude compared to all previous observations. We were able to estimate the star's rotation period, of 8.9 h, and discuss a possible determination of the rate of period change of (2.0 ± 0.9) × 10−13 s s −1, the first such estimate for a DBV.

Published
2011
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240. Brown Dwarf Companions to White Dwarfs

Author

Burleigh, M. R., Steele, P. R., Dobbie, P. D., Farihi, J., Napiwotzki, R., Maxted, P. F. L., Barstow, M. A., Jameson, R. F., Casewell, S. L., Gänsicke, B. T., and Marsh, T. R.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

Brown dwarf companions to white dwarfs are rare, but recent infra-red surveys are slowly reveal- ing examples. We present new observations of the post-common envelope binary WD0137-349, which reveals the effects of irradiation on the ~ 0.05M* secondary, and new observations of GD 1400 which show that it too is a close, post-comon envelope system. We also present the lat- est results in a near-infrared photometric search for unresolved ultracool companions and to white dwarfs with UKIDSS. Twenty five DA white dwarfs were identified as having photometric excesses indicative of a low mass companion, with 8-10 of these having a predicted mass in the range asso- ciated with brown dwarfs. The results of this survey show that the unresolved (< 2") brown dwarf companion fraction to DA white dwarfs is 0.3 \leq fWD+BD \leq 1.3%., Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.6606

Published
2011
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241. A possible solution to the Lyman/Balmer line problem in hot DA white dwarfs

Author

Preval, S. P., Barstow, M. A., Badnell, N. R., Holberg, J. B., Hubeny, I., Preval, S. P., Barstow, M. A., Badnell, N. R., Holberg, J. B., and Hubeny, I.

Abstract

Arguably, the best method for determining the effective temperature ($T_{\mathrm{eff}}$) and surface gravity (log $g$) of a DA white dwarf is by fitting the Hydrogen Lyman and Balmer absorption features. However, as has been shown for white dwarfs with $T_{\mathrm{eff}}$>50,000K, the calculated value from the Lyman and Balmer lines are discrepant, which worsens with increasing temperature. Many different solutions have been suggested, ranging from the input physics used to calculate the models, to interstellar reddening. We will focus on the former, and consider three variables. The first is the atomic data used, namely the number of transitions included in line blanketing treatments and the photoionization cross sections. The second is the stark broadening treatment used to synthesise the Lyman and Balmer line profiles, namely the calculations performed by Lemke (1997) and Tremblay & Bergeron (2009). Finally, the third is the atmospheric content. The model grids are calculated with a pure H composition, and a metal polluted composition using the abundances of Preval et al. (2013). We present the preliminary results of our analysis, whereby we have determined the $T_{\mathrm{eff}}$ for a small selection of white dwarfs. We plan to extend our analysis by allowing metallicity to vary in future model grids., Comment: 5 pages, 1 figure, 1 table: To appear in the proceedings of the "19th European White Dwarf Workshop" in Montreal, Canada, 2014

Published
2014

242. White paper: Gaia and the end states of stellar evolution

Author

Barstow, M. A, Casewell, S. L., Catalan, S., Copperwheat, C., Gaensicke, B., Garcia-Berro, E., Hambly, N., Heber, U., Holberg, J., Isern, J., Jeffery, S., Jordan, S., Lawrie, K. A., Lynas-Gray, A. E., Maccarone, T., Marsh, T., Parsons, S., Silvotti, R., Subasavage, J., Torres, S., Wheatley, P., Barstow, M. A, Casewell, S. L., Catalan, S., Copperwheat, C., Gaensicke, B., Garcia-Berro, E., Hambly, N., Heber, U., Holberg, J., Isern, J., Jeffery, S., Jordan, S., Lawrie, K. A., Lynas-Gray, A. E., Maccarone, T., Marsh, T., Parsons, S., Silvotti, R., Subasavage, J., Torres, S., and Wheatley, P.

Abstract

This is the product of a Gaia GREAT workshop on "Gaia and the end states of stellar evolution" held at the University of Leicester in April 2011.

Published
2014

243. Evidence for an external origin of heavy elements in hot DA white dwarfs

Author

Barstow, M. A., Barstow, J. K., Casewell, S. L., Holberg, J. B., Hubeny, I., Barstow, M. A., Barstow, J. K., Casewell, S. L., Holberg, J. B., and Hubeny, I.

Abstract

We present a series of systematic abundance measurements for 89 hydrogen atmosphere (DA-type) white dwarfs with temperatures spanning 16000-77000K drawn from the FUSE spectral archive. This is the largest study to date of white dwarfs where radiative forces are significant, exceeding our earlier work, based mainly on IUE and HST data, by a factor three. Using heavy element blanketed non-LTE stellar atmosphere calculations, we have addressed the heavy element abundance patterns making completely objective measurements of abundance values and their error ranges using a \c{hi}2 fitting technique. We are able to establish the broad range of abundances seen in a given temperature range and establish the incidence of stars which appear, in the optical, to be atmospherically devoid of any material other than H. We compare the observed abundances to predictions of radiative levitation calculations, revealing little agreement. We propose that the supply of heavy elements is accreted from external sources rather than being intrinsic to the star. These elements are then retained in the white dwarf atmospheres by radiative levitation, a model that can explain both the diversity of measured abundances for stars of similar temperature and gravity, including cases with apparently pure H envelopes, and the presence of photospheric metals at temperatures where radiative levitation is no longer effective., Comment: 23 pages. 13 Figures, 4 Tables. Accepted for publication in the Monthly Notices of the Royal Astronomical Society

Published
2014
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244. PHL 5038: A spatially resolved white dwarf + brown dwarf binary

Author

Steele, P. R., Burleigh, M. R., Farihi, J., Gaensicke, B. T., Jameson, R. F., Dobbie, P. D., and Barstow, M. A.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics - Astrophysics of Galaxies, Solar and Stellar Astrophysics (astro-ph.SR), QB
Abstract

A near-infrared excess is detected at the white dwarf PHL5038 in UKIDSS photometry, consistent with the presence of a cool, substellar companion. We have obtained H- and K-grism spectra and images of PHL5038 using NIRI on Gemini North. The target is spatially and spectrally resolved into two components; an 8000K DA white dwarf, and a likely L8 brown dwarf companion, separated by 0.94". The spectral type of the secondary was determined using standard spectral indices for late L and T dwarfs. The projected orbital separation of the binary is 55AU, and so it becomes only the second known wide WD+dL binary to be found after GD165AB. This object could potentially be used as a benchmark for testing substellar evolutionary models at intermediate to older ages., Comment: 5 pages, 3 figures, accepted to A&A

Published
2009
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245. A search for binarity using FUSE observations of DAO white dwarfs

Author

Good, S. A., Barstow, M. A., Burleigh, M. R., Dobbie, P. D., and Holberg, J. B.

Subjects
Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics
Abstract

We report on a search for evidence of binarity in Far-Ultraviolet Spectroscopic Explorer (FUSE) observations of DAO white dwarfs. Spectra recorded by FUSE are built up from a number of separate exposures. Observation of changes in the position of photospheric heavy element absorption lines between exposures, with respect to the stationary interstellar medium lines, would reveal radial velocity changes - evidence of the presence of a binary system. This technique is successful in picking out all the white dwarfs already known to be binaries, which comprise 5 out of the sample of 16, but significant radial velocity shifts were found for only one additional star, Ton 320. This object is also known to have an infrared excess. DAOs can be separated broadly into low or normal mass objects. Low mass white dwarfs can be formed as a result of binary evolution, but it has been suggested that the lower mass DAOs evolve as single stars from the extended horizontal branch, and we find no evidence of binarity for 8 out of the 12 white dwarfs with relatively low mass. The existence of higher mass DAOs can also be explained if they are within binary systems, but of the four higher mass stars in the sample studied, PG 1210+533 and LB 2 do not exhibit significant radial velocity shifts, although there were only two exposures for the former object and the latter has an infrared excess., 9 pages, 9 figures. Accepted for publication in MNRAS

Published
2005

246. Hot DA white dwarf model atmosphere calculations: including improved Ni PI cross-sections.

Author

Preval, S. P., Barstow, M. A., Badnell, N. R., Hubeny, I., and Holberg, J. B.

Subjects
*WHITE dwarf stars, *NUCLEAR cross sections, *NICKEL, *PHOTOIONIZATION, *ULTRAVIOLET astronomy
Abstract

To calculate realistic models of objects with Ni in their atmospheres, accurate atomic data for the relevant ionization stages need to be included in model atmosphere calculations. In the context of white dwarf stars, we investigate the effect of changing the Ni IV-VI bound-bound and bound-free atomic data on model atmosphere calculations. Models including photoionization cross-section (PICS) calculated with AUTOSTRUCTURE show significant flux attenuation of up to ~80 per cent shortward of 180 Å in the extreme ultraviolet (EUV) region compared to a model using hydrogenic PICS. Comparatively, models including a larger set of Ni transitions left the EUV, UV, and optical continua unaffected. We use models calculated with permutations of these atomic data to test for potential changes to measured metal abundances of the hot DA white dwarf G191-B2B. Models including AUTOSTRUCTURE PICS were found to change the abundances of N and O by as much as ~22 per cent compared to models using hydrogenic PICS, but heavier species were relatively unaffected. Models including AUTOSTRUCTURE PICS caused the abundances of N/O IV and V to diverge. This is because the increased opacity in the AUTOSTRUCTURE PICS model causes these charge states to form higher in the atmosphere, more so for N/O V. Models using an extended line list caused significant changes to the Ni IV-V abundances. While both PICS and an extended line list cause changes in both synthetic spectra and measured abundances, the biggest changes are caused by using AUTOSTRUCTURE PICS for Ni. [ABSTRACT FROM AUTHOR]

Published
2017
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247. Hubble Space Telescope Spectroscopy of the Balmer lines in Sirius B

Author

Barstow, M. A., Bond, Howard E., Holberg, J. B., Burleigh, M. R., Hubeny, I., and Koester, D.

Subjects
Astrophysics (astro-ph), Astrophysics::Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Sirius B is the nearest and brightest of all white dwarfs, but it is very difficult to observe at visible wavelengths due to the overwhelming scattered light contribution from Sirius A. However, from space we can take advantage of the superb spatial resolution of the Hubble Space Telescope to resolve the A and B components. Since the closest approach in 1993, the separation between the two stars has become increasingly favourable and we have recently been able to obtain a spectrum of the complete Balmer line series for Sirius B using HST?s Space Telescope Imaging Spectrograph (STIS). The quality of the STIS spectra greatly exceed that of previous ground-based spectra, and can be used to provide an important determination of the stellar temperature (Teff = 25193K) and gravity (log g = 8.556). In addition we have obtained a new, more accurate, gravitational red-shift of 80.42 +/- 4.83 km s-1 for Sirius B. Combining these results with the photometric data and the Hipparcos parallax we obtain new determinations of the stellar mass for comparison with the theoretical mass-radius relation. However, there are some disparities between the results obtained independently from log g and the gravitational redshift which may arise from flux losses in the narrow 50x0.2arcsec slit. Combining our measurements of Teff and log g with the Wood (1995) evolutionary mass-radius relation we get a best estimate for the white dwarf mass of 0.978 M. Within the overall uncertainties, this is in agreement with a mass of 1.02 M obtained by matching our new gravitational red-shift to the theoretical M/R relation., Comment: 11 pages, 6 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society

Published
2005
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248. Metal Abundances in Hot DA White Dwarfs

Author

Schuh, S., Barstow, M. A., and Dreizler, S.

Subjects
Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We compare measured element abundances in hot DA white dwarfs from UV observations to predictions from our self-consistent non-LTE model atmosphere diffusion calculations., 4 pages, 2 figures, to appear in the proceedings of the 14th European Workshop on White Dwarfs, eds. D. Koester and S. Moehler, ASP Conf. Series

Published
2004

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