Author: "Simon Hodgkin" - Searchworks@Jio Institute Digital Library Search Results

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149 results on '"Simon Hodgkin"'

1. WD 0141−675: a case study on how to follow-up astrometric planet candidates around white dwarfs

Author: Laura K Rogers, John Debes, Richard J Anslow, Amy Bonsor, S L Casewell, Leonardo A Dos Santos, Patrick Dufour, Boris T. Gänsicke, Nicola Gentile Fusillo, Detlev Koester, Louise Dyregaard Nielsen, Zephyr Penoyre, Emily L Rickman, Johannes Sahlmann, Pier-Emmanuel Tremblay, Andrew Vanderburg, Siyi Xu, Erik Dennihy, Jay Farihi, J J Hermes, Simon Hodgkin, Mukremin Kilic, Piotr M Kowalski, Hannah Sanderson, and Silvia Toonen
Published: 2023
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2. Periodic stellar variability from almost a million NGTS light curves

Author: Joshua T Briegal, Edward Gillen, Didier Queloz, Simon Hodgkin, Jack S Acton, David R Anderson, David J Armstrong, Matthew P Battley, Daniel Bayliss, Matthew R Burleigh, Edward M Bryant, Sarah L Casewell, Jean C Costes, Philipp Eigmüller, Samuel Gill, Michael R Goad, Maximilian N Günther, Beth A Henderson, James A G Jackman, James S Jenkins, Lars T Kreutzer, Maximiliano Moyano, Monika Lendl, Gareth D Smith, Rosanna H Tilbrook, Christopher A Watson, Richard G West, and Peter J Wheatley
Published: 2022
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3. Eclipsing white dwarf binaries in Gaia and the Zwicky Transient Faaccility

Author: Vasily Belokurov, Pascal M. Keller, Jim M. Wild, Ignacio García-Soriano, Elmé Breedt, Simon Hodgkin, and Jacob L. Wise
Subjects: Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, FOS: Physical sciences, Astronomy, White dwarf, Astronomy and Astrophysics, Transient (computer programming), Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Gaia provided the largest-ever catalogue of white dwarf stars. We use this catalogue, along with the third public data release of the Zwicky Transient Facility (ZTF), to identify new eclipsing white dwarf binaries. Our method exploits light curve statistics and the Box Least Squares algorithm to detect periodic light curve variability. The search revealed 18 new binaries, of which 17 are eclipsing. We use the position in the Gaia H-R diagram to classify these binaries and find that the majority of these white dwarfs have main sequence companions. We identify one system as a candidate eclipsing white dwarf--brown dwarf binary and a further two as extremely low mass (ELM) white dwarf binaries. We also provide identification spectroscopy for 17 of our 18 binaries. Running our search method on mock light curves with real ZTF sampling, we estimate our efficiency of detecting objects with light curves similar to the ones of the newly discovered binaries. Many more binaries are to be found in the ZTF footprint as the data releases grow, so our survey is ongoing., Comment: 19 pages, 15 figures, 5 tables, accepted for publication by MNRAS
Published: 2021
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4. NGTS-19b: a high-mass transiting brown dwarf in a 17-d eccentric orbit

Author: Jack S. Acton, Stéphane Udry, Nolan Grieves, Douglas R. Alves, Matthew R. Burleigh, Edward M. Bryant, Sarah L. Casewell, Samuel Gill, James A. G. Jackman, Maximiliano Moyano, James S. Jenkins, David R. Anderson, Monika Lendl, Hannah L. Worters, Szilard Csizmadia, Philipp Eigmüller, Simon Hodgkin, Michael R. Goad, Fran cois Bouchy, Richard P. Nelson, Richard G. West, Maximilian N. Günther, James McCormac, Alexis M. S. Smith, Peter J. Wheatley, H. Breytenbach, Matthew P. Battley, Ramotholo Sefako, Daniel Bayliss, Beth A. Henderson, Jessymol K. Thomas, Jose I. Vines, Rosanna H. Tilbrook, M. Stalport, Edward Gillen, Louise D. Nielsen, and Gareth Smith
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Brown dwarf, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Orbital eccentricity, Radius, 01 natural sciences, Exoplanet, Radial velocity, techniques: photometric, Photometry (astronomy), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, techniques: radial velocities, 0103 physical sciences, Spectral energy distribution, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), brown dwarfs, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the discovery of NGTS-19b, a high mass transiting brown dwarf discovered by the Next Generation Transit Survey (NGTS). We investigate the system using follow up photometry from the South African Astronomical Observatory, as well as sector 11 TESS data, in combination with radial velocity measurements from the CORALIE spectrograph to precisely characterise the system. We find that NGTS-19b is a brown dwarf companion to a K-star, with a mass of $69.5 ^{+5.7}_{-5.4}$ M$_{Jup}$ and radius of $1.034 ^{+0.055}_{-0.053}$ R$_{Jup}$. The system has a reasonably long period of 17.84 days, and a high degree of eccentricity of $0.3767 ^{+0.0061}_{-0.0061}$. The mass and radius of the brown dwarf imply an age of $0.46 ^{+0.26}_{-0.15}$ Gyr, however this is inconsistent with the age determined from the host star SED, suggesting that the brown dwarf may be inflated. This is unusual given that its large mass and relatively low levels of irradiation would make it much harder to inflate. NGTS-19b adds to the small, but growing number of brown dwarfs transiting main sequence stars, and is a valuable addition as we begin to populate the so called brown dwarf desert., Accepted for Publication in MNRAS
Published: 2021
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5. Stellar flares detected with the Next Generation Transit Survey

Author: James A. G. Jackman, Jack S. Acton, Michael R. Goad, Rosanna H. Tilbrook, Didier Queloz, Edward Gillen, Sarah L. Casewell, Boris T. Gänsicke, Samuel Gill, Simon Hodgkin, Maximilian N. Günther, David R. Anderson, Richard G. West, Liam Raynard, Beth A. Henderson, Joshua T. Briegal, Chloe E. Pugh, Daniel Bayliss, Matthew R. Burleigh, James S. Jenkins, Peter J. Wheatley, Christopher A. Watson, Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository
Subjects: 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Stellar classification, 01 natural sciences, law.invention, stars: rotation, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), skin and connective tissue diseases, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Starspot, Astronomy and Astrophysics, Thin disc, starspots, Stars, Amplitude, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, stars: flare, Astrophysics::Earth and Planetary Astrophysics, Data release, Astrophysics - Earth and Planetary Astrophysics, Flare
Abstract: We present the results of a search for stellar flares in the first data release from the Next Generation Transit Survey (NGTS). We have found 610 flares from 339 stars, with spectral types between F8 and M6, the majority of which belong to the Galactic thin disc. We have used the 13 second cadence NGTS lightcurves to measure flare properties such as the flare amplitude, duration and bolometric energy. We have measured the average flare occurrence rates of K and early to mid M stars and present a generalised method to measure these rates while accounting for changing detection sensitivities. We find that field age K and early M stars show similar flare behaviour, while fully convective M stars exhibit increased white-light flaring activity, which we attribute to their increased spin down time. We have also studied the average flare rates of pre-main sequence K and M stars, showing they exhibit increased flare activity relative to their main sequence counterparts., 21 pages, 13 figures, 5 tables. Accepted for publication in the Monthly Notices of the Royal Astronomical Society
Published: 2021
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6. NGTS 15b, 16b, 17b, and 18b: four hot Jupiters from the Next-Generation Transit Survey

Author: Jessymol K. Thomas, Stéphane Udry, Alexander Chaushev, Matthew R. Burleigh, Louise D. Nielsen, Alexis M. S. Smith, Michael R. Goad, Richard G. West, James McCormac, Liam Raynard, James S. Jenkins, Sarah L. Casewell, Benjamin F. Cooke, Rosanna H. Tilbrook, François Bouchy, Ramotholo Sefako, Peter J. Wheatley, Beth A. Henderson, Joshua T. Briegal, Christopher A. Watson, Jose I. Vines, Daniel Bayliss, J. Costes, Jack S. Acton, Hannah L. Worters, Simon Hodgkin, Didier Queloz, H. Breytenbach, Samuel Gill, Maximiliano Moyano, Monika Lendl, Edward Gillen, David R. Anderson, Maximilian N. Günther, Philipp Eigmüller, Aleisha Hogan, David J. Armstrong, Douglas R. Alves, Edward M. Bryant, Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Inflation (cosmology), planets and satellites: detection, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, Planetary system, Parameter space, 01 natural sciences, planets and satellites: gaseous planets, Space and Planetary Science, Planet, 0103 physical sciences, Hot Jupiter, Transit (astronomy), 10. No inequality, planetary systems, 010303 astronomy & astrophysics, Main sequence, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of four new hot Jupiters with the Next Generation Transit Survey (NGTS). NGTS-15b, NGTS-16b, NGTS-17b, and NGTS-18b are short-period ($P, Accepted for publication in MNRAS
Published: 2021
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7. Gaia Early Data Release 3 The Gaia Catalogue of Nearby Stars

Author: Zoltan Balog, G. Tauran, Vincenzo Ripepi, Gerry Gilmore, M. Barros, Łukasz Wyrzykowski, Alberto Cellino, E. Poggio, P. Gavras, Simchon Faigler, Marc Audard, C. Nicolas, M. Vaillant, A. Mora, Paolo Tanga, Silvio Leccia, Despina Hatzidimitriou, A. Dapergolas, Eva Sciacca, Alberto Krone-Martins, N. Cheek, M. Hauser, Ulrike Heiter, S. Managau, L. Rohrbasser, Mathias Schultheis, E. Utrilla, Minia Manteiga, Marcella Marconi, Xavier Luri, F. De Angeli, Shay Zucker, Paolo Giacobbe, J. Juaristi Campillo, H. I. Siddiqui, J. Torra, F. X. Pineau, Roy Gomel, Thierry Morel, T. Cornez, Eric Gosset, Mario Gai, Jose M Hernandez, G. Giuffrida, A. de Torres, Laszlo Szabados, S. Ragaini, E. van Dillen, D. Semeux, Leanne P. Guy, R. Drimmel, L. M. Sarro, S. Voutsinas, Johannes Sahlmann, Damien Ségransan, S. Liao, Derek W. Morris, Jan Rybizki, André Moitinho, T. Roegiers, Bengt Edvardsson, Tristan Cantat-Gaudin, Martin Altmann, C. Turon, Laurent Chemin, K. Janßen, D. Garabato, Alejandra Recio-Blanco, Michał Pawlak, Lorenzo Rimoldini, Sergei A. Klioner, F. Torra, Carine Babusiaux, Alfred Castro-Ginard, G. Plum, Mariateresa Crosta, Iain A. Steele, A. Yoldas, Alex Lobel, J.-L. Bassilana, Harry Enke, Rosanna Sordo, Francesca Fragkoudi, F. De Luise, M. Bernet, Alessandro Sozzetti, M. Kontizas, Roberto Molinaro, C. Diener, S. Regibo, D. Barbato, T. Pauwels, R. E. de Souza, C. Fabricius, D. Souami, L. Martin Polo, M. Ramos-Lerate, Douglas J. Marshall, A. G. Butkevich, P. Madrero Pardo, P. Re Fiorentin, J. F. Le Campion, Jérôme Berthier, N. Tonello, Ummi Abbas, Y. Lebreton, M. Biermann, D. Munoz, N. Brouillet, David Teyssier, O. Vanel, P. A. Palicio, A. Jean-Antoine Piccolo, A. F. Lanza, Jesus Salgado, E. del Pozo, Antti Penttilä, R. Geyer, Ramachrisna Teixeira, L. Chaoul, Mike Smith, Rossella Cancelliere, J. M. Martín-Fleitas, D. Baines, M. Romero-Gómez, E. Anglada Varela, E. Livanou, X. Peñalosa Esteller, S. Diakite, Alberto Vecchiato, Thomas Wevers, Daniel Hestroffer, Sebastian L. Hidalgo, M. David, Angela Bragaglia, J. De Ridder, Mark Taylor, Roberto Morbidelli, A. Sagristà Sellés, Nigel Hambly, Arnaud Siebert, R. L. Smart, P. Burgess, Y. Le Fustec, Alessandro Bressan, H. Steidelmüller, Alberto Riva, H. E. Huckle, Morgan Fouesneau, N. Bauchet, P. Osborne, S. Marinoni, Krzysztof A. Rybicki, A. Masip, Laia Casamiquela, R. Messineo, A. Garofalo, Antonella Vallenari, R. Mor, Sahar Shahaf, P. de Laverny, G. Sadowski, Peter G. Jonker, A. Kochoska, F. Taris, A. F. Mulone, M. Ajaj, C. Ducourant, T. A. Lister, F. A. Jansen, Ruth Carballo, J. M. Carrasco, Tatiana Muraveva, W. van Reeven, P. Sartoretti, Jordi Portell, Andreas Korn, E. Salguero, Ana Ulla, P. Di Matteo, Coryn A. L. Bailer-Jones, J. Bakker, F. Riclet, G. Altavilla, Ulrich Bastian, P. Esquej, R. Buzzi, M. Segol, A. C. Lanzafame, L. Balaguer-Núñez, Beatrice Bucciarelli, C. Panem, E. Balbinot, T. Carlucci, Davide Massari, P. de Teodoro, Sébastien Lambert, M. I. Carnerero, Amina Helmi, F. Solitro, C. Robin, Carlos Dafonte, Tsevi Mazeh, A. Panahi, C. Fabre, Sergi Blanco-Cuaresma, Deborah Busonero, Maroussia Roelens, O. Marchal, Tomaz Zwitter, B. Holl, G. Holland, William Thuillot, Michael Davidson, E. Licata, Michele Bellazzini, Teresa Antoja, E. Szegedi-Elek, Francesca Figueras, Eric Slezak, Sergio Messina, N. Samaras, E. Poujoulet, Mark Cropper, A. Burlacu, R. Blomme, Elmé Breedt, Annie C. Robin, H. E. Delgado, Z. Kostrzewa-Rutkowska, Georges Kordopatis, Conny Aerts, L. Noval, Daniel Michalik, P. J. Richards, L. Karbevska, Grigori Fedorets, Maria Süveges, F. Crifo, J. Guiraud, D. Eappachen, K. Kruszyńska, Gisella Clementini, P. Yvard, Carme Jordi, L. Bramante, G. Busso, P. David, E. Fraile, Ugo Becciani, A. Lorca, Sanjeev Khanna, Alex Bombrun, Isabella Pagano, C. Dolding, A. M. Piersimoni, Paolo Montegriffo, A. Abreu Aramburu, Anthony G. A. Brown, Simon Hodgkin, Ennio Poretti, M. Fabrizio, I. Gonzalez-Santamaria, N. A. Walton, P. Panuzzo, Benoit Carry, Raphael Guerra, J. J. González-Vidal, T. Lebzelter, Nami Mowlavi, C. Barache, M. M. S. Marcos Santos, S. Cowell, Marco Castellani, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, N. Leclerc, S. Bartolomé, J. Álvarez Cid-Fuentes, F. van Leeuwen, S. Bouquillon, Uwe Lammers, D. W. Evans, L. Eyer, M. van Leeuwen, A. Guerrier, J. González-Núñez, H. E. P. Lindstrøm, Miguel García-Torres, Ilaria Musella, L. Palaversa, W. Roux, W. Löffler, J.-B. Delisle, Dimitri Pourbaix, Timo Prusti, J. Osinde, M. Riello, G. Orrù, C. Crowley, Alessandra Mastrobuono-Battisti, Hector Canovas, D. L. Harrison, Y. Lasne, E. F. del Peloso, Laurent Galluccio, N. Hładczuk, T. Boch, Martin A. Barstow, László Molnár, Aldo Dell'Oro, C. Pagani, Krzysztof Nienartowicz, Stefano Bertone, Patrick Charlot, Eduard Masana, Elisabetta Caffau, N. Robichon, Luciana Bianchi, Federica Spoto, Felix Franke, J. L. Halbwachs, R. Gutiérrez-Sánchez, L. Pulone, Yassine Damerdji, Frédéric Arenou, Richard I. Anderson, Elena Pancino, David Hobbs, P. Castro Sampol, Yves Fremat, Pierre Kervella, C. Zurbach, Sofia Randich, Robert G. Mann, J. C. Segovia, Diego Bossini, D. Katz, Nicholas Rowell, P. Ramos, E. Racero, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Enrique Solano, S. G. Baker, W. J. Cooper, F. Royer, S. Accart, George M. Seabroke, João Alves, Emese Plachy, Thomas Hilger, Pedro García-Lario, Gérard Jasniewicz, Kevin Benson, Christos Siopis, J. Souchay, Agnes Fienga, Giovanni Comoretto, F. Julbe, A. Hutton, Pierre Fernique, Céline Reylé, F. Pailler, Stefan Jordan, J. H. J. de Bruijne, C. A. Stephenson, E. Gerlach, Elisa Distefano, Karri Muinonen, Y. Viala, H. Zhao, L. Siltala, C. P. Murphy, Maria-Rosa L. Cioni, Andrea Chiavassa, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, Federico Marocco, Nicoletta Sanna, Alexey Mints, Juan Zorec, Ángel Gómez, I. Bellas-Velidis, M. G. Lattanzi, C. M. Raiteri, E. Brugaletta, Mikael Granvik, O. L. Creevey, Guy Rixon, Francois Mignard, P. M. Marrese, M. A. Álvarez, Caroline Soubiran, Rene Andrae, C. Ordénovic, A. Delgado, V. Sanchez Gimenez, J. Castañeda, D. Vicente, R. De March, A. Garcia-Gutierrez, M. Weiler, F. Thévenin, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Jon Marchant, Monica Rainer, Alessandro Spagna, Andrej Prsa, M. Sarasso, Nicolas Rambaux, Paul J. McMillan, Ludovic Delchambre, M. Garcia-Reinaldos, M. Haywood, C. Fouron, S. Girona, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Universidad de Barcelona, Xunta de Galicia, Generalitat de Catalunya, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), 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), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), 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), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 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, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), 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), Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], 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), 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), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Mésocentre de calcul (MESOCENTRE), Université de Franche-Comté (UFC), Centre de Données Astronomiques de Strasbourg, Partenaires INRAE, Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), THALES, Université de Namur [Namur] (UNamur), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université Nice Sophia Antipolis (1965 - 2019) (UNS), 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), Universität Heidelberg [Heidelberg] = Heidelberg University-Universität Heidelberg [Heidelberg] = Heidelberg University, Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), THALES [France], Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Universidad de Cantabria, Gaia Collaboration, Planetary-system research, Department of Physics, Particle Physics and Astrophysics, Astronomy, and ITA
Subjects: trigonometric parallaxes, Solar neighborhood, Stars: luminosity function, mass function, Astronomy, Astrophysics, 01 natural sciences, luminosity function, mass function [Stars], Astronomi, astrofysik och kosmologi, luminosity: mass function [Stars], Astronomy, Astrophysics and Cosmology, MAIN-SEQUENCE, Hertzsprung-Russell-diagram, 010303 astronomy & astrophysics, Stars:low-mass brown-dwarfs, wide binaries, Physics, education.field_of_study, north galactic pole, Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, BROWN DWARF, Astrophysics - Solar and Stellar Astrophysics, mass function, NORTH GALACTIC POLE, Physical Sciences, symbols, CIRCULAR-VELOCITY CURVE, Halo, astro-ph.SR, Hertzsprung–Russell diagram, stars: luminosity function, astro-ph.GA, Posterior probability, Population, main-sequence, Luminosity-Function, FOS: Physical sciences, Mass-Function, Astronomy & Astrophysics, Computer Science::Digital Libraries, Photometry (optics), DWARF LUMINOSITY-FUNCTION, dwarf luminosity-function, sky-survey, symbols.namesake, Settore FIS/05 - Astronomia e Astrofisica, luminosity function [stars], low-mass [Stars], 0103 physical sciences, Stars: luminosity: mass function, Stars: low-mass, WHITE-DWARFS, education, Solar and Stellar Astrophysics (astro-ph.SR), brown dwarf, catalogs, astrometry, Hertzsprung-Russell and C-M diagrams, stars: low-mass, solar neighborhood, Astrophysics - Astrophysics of Galaxies, SKY-SURVEY, white-dwarfs, Science & Technology, 010308 nuclear & particles physics, Luminosity function, White dwarf, TRIGONOMETRIC PARALLAXES, Astronomy and Astrophysics, Low-mass, 115 Astronomy, Space science, WIDE BINARIES, Stars, Physics::History of Physics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), solar-neighborhood, Catalogs, circular-velocity curve, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Aims. We produce a clean and well-characterised catalogue of objects within 100 pc of the Sun from the Gaia Early Data Release 3. We characterise the catalogue through comparisons to the full data release, external catalogues, and simulations. We carry out a first analysis of the science that is possible with this sample to demonstrate its potential and best practices for its use., Methods. Theselection of objects within 100 pc from the full catalogue used selected training sets, machine-learning procedures, astrometric quantities, and solution quality indicators to determine a probability that the astrometric solution is reliable. The training set construction exploited the astrometric data, quality flags, and external photometry. For all candidates we calculated distance posterior probability densities using Bayesian procedures and mock catalogues to define priors. Any object with reliable astrometry and a non-zero probability of being within 100 pc is included in the catalogue., Results. We have produced a catalogue of 331 312 objects that we estimate contains at least 92% of stars of stellar type M9 within 100 pc of the Sun. We estimate that 9% of the stars in this catalogue probably lie outside 100 pc, but when the distance probability function is used, a correct treatment of this contamination is possible. We produced luminosity functions with a high signal-to-noise ratio for the main-sequence stars, giants, and white dwarfs. We examined in detail the Hyades cluster, the white dwarf population, and wide-binary systems and produced candidate lists for all three samples. We detected local manifestations of several streams, superclusters, and halo objects, in which we identified 12 members of Gaia Enceladus. We present the first direct parallaxes of five objects in multiple systems within 10 pc of the Sun., Conclusions. We provide the community with a large, well-characterised catalogue of objects in the solar neighbourhood. This is a primary benchmark for measuring and understanding fundamental parameters and descriptive functions in astronomy.
Published: 2021
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8. NGTS clusters survey – II. White-light flares from the youngest stars in Orion

Author: Christopher A. Watson, Samuel Gill, Maximiliano Moyano, Claudia Belardi, Michael R. Goad, Sarah L. Casewell, Richard G. West, James McCormac, Liam Raynard, Peter J. Wheatley, David R. Anderson, Matthew R. Burleigh, Jack S. Acton, James S. Jenkins, Simon Hodgkin, Philipp Eigmüller, Rosanna H. Tilbrook, James A. G. Jackman, Edward Gillen, Andrew Grange, Didier Queloz, Apollo - University of Cambridge Repository, and Queloz, Didier [0000-0002-3012-0316]
Subjects: Extrasolare Planeten und Atmosphären, endocrine system, astro-ph.SR, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Library science, stars: pre-main-sequence, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Queen (playing card), stars: low-mass, 0103 physical sciences, White light, Astrophysics::Solar and Stellar Astrophysics, skin and connective tissue diseases, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, astro-ph.EP, Physics::Space Physics, stars: flare, Administration (government), Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the detection of high energy white-light flares from pre-main sequence stars associated with the Orion complex, observed as part of the Next Generation Transit Survey (NGTS). With energies up to $5.2\times10^{35}$ erg these flares are some of the most energetic white-light flare events seen to date. We have used the NGTS observations of flaring and non-flaring stars to measure the average flare occurrence rate for 4 Myr M0-M3 stars. We have also combined our results with those from previous studies to predict average rates for flares above $1\times10^{35}$ ergs for early M stars in nearby young associations., Comment: 10 pages, 5 figures, 5 tables. Accepted for publication in the Monthly Notices of the Royal Astronomical Society
Published: 2020
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9. Progenitor, precursor, and evolution of the dusty remnant of the stellar merger M31-LRN-2015

Author: Peter Nugent, J. E. Jencson, Mansi M. Kasliwal, Christopher S. Kochanek, Karambelkar, Frank J. Masci, Joel Johansson, Scott M. Adams, S. Kozlowski, Nadejda Blagorodnova, H Campbell, Umaa Rebbapragada, R. R. Laher, Subo Dong, and Simon Hodgkin
Subjects: close [binaries], Andromeda Galaxy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astronomy & Astrophysics, 01 natural sciences, Photometry (optics), Common envelope, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Roche lobe, Spectroscopy, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, extinction, jets and outflows [ISM], 010308 nuclear & particles physics, Astronomy and Astrophysics, Stem Cell Research, Light curve, Astrophysics - Astrophysics of Galaxies, novae [transients], Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, evolution [stars], Astrophysics of Galaxies (astro-ph.GA), Spectral energy distribution, dust, Astrophysics::Earth and Planetary Astrophysics, Astronomical and Space Sciences
Abstract: M31-2015-LRN is a likely stellar merger discovered in the Andromeda Galaxy in 2015. We present new optical to mid-infrared photometry and optical spectroscopy for this event. Archival data shows that the source started to brighten $\sim$2 years before the nova event. During this precursor phase, the source brightened by $\sim$3 mag. The lightcurve at 6 and 1.5 months before the main outburst may show periodicity, with periods of 16$\pm$0.3 and 28.1$\pm$1.4 days respectively. This complex emission may be explained by runaway mass loss from the system after the binary undergoes Roche-lobe overflow, leading the system to coalesce in tens of orbital periods. While the progenitor spectral energy distribution shows no evidence of pre-existing warm dust in system, the remnant forms an optically thick dust shell at $\sim$4 months after the outburst peak. The optical depth of the shell increases dramatically after 1.5 years, suggesting the existence of shocks that enhance the dust formation process. We propose that the merger remnant is likely an inflated giant obscured by a cooling shell of gas with mass $\sim0.2$ M$_{\odot}$ ejected at the onset of the common envelope phase., Comment: 16 pages, 10 figures. Accepted for publication in MNRAS
Published: 2020
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10. WTS-2 b: a hot Jupiter orbiting near its tidal destruction radius around a K dwarf

Author: Carole A. Haswell, N. Goulding, Johannes Koppenhoefer, Amelia Bayo, Jorge Lillo-Box, S. V. Nefs, J. Zendejas, Enrique Solano, D. J. Pinfield, R. Tata, M. C. Gálvez-Ortiz, E. J. W. de Mooij, E. L. Martín, M. Cappetta, C. del Burgo, Matthew A. Kenworthy, Simon Hodgkin, P. Cruz, Ignas Snellen, Jayne Birkby, B. Sipőcz, John R. Barnes, Roberto P. Saglia, Yakiv V. Pavlenko, Felipe Murgas, S. Catalán, Géza Kovács, Alexander J. Mustill, Luca Fossati, P. R. Steele, David A. Campbell, M. Kuznetsov, David Barrado, Enric Palle, D. Mislis, O. Ivanyuk, H. Stoev, and Nicolas Lodieu
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Orbital decay, Light curve, Exoplanet, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, Hot Jupiter, Roche lobe, Astrophysics::Earth and Planetary Astrophysics, Jupiter mass, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of WTS-2 b, an unusually close-in 1.02-day hot Jupiter (Mp=1.12MJ, Rp=1.363RJ) orbiting a K2V star, which has a possible gravitationally-bound M-dwarf companion at 0.6 arcsec separation contributing ~20 percent of the total flux in the observed J-band light curve. The planet is only 1.5 times the separation from its host star at which it would be destroyed by Roche lobe overflow, and has a predicted remaining lifetime of just ~40 Myr, assuming a tidal dissipation quality factor of Q'*=10^6. Q'* is a key factor in determining how frictional processes within a host star affect the orbital evolution of its companion giant planets, but it is currently poorly constrained by observations. We calculate that the orbital decay of WTS-2 b would correspond to a shift in its transit arrival time of T_shift~17 seconds after 15 years assuming Q'*=10^6. A shift less than this would place a direct observational constraint on the lower limit of Q'* in this system. We also report a correction to the previously published expected T_shift for WASP-18 b, finding that T_shift=356 seconds after 10 years for Q'*=10^6, which is much larger than the estimated 28 seconds quoted in WASP-18 b discovery paper. We attempted to constrain Q'* via a study of the entire population of known transiting hot Jupiters, but our results were inconclusive, requiring a more detailed treatment of transit survey sensitivities at long periods. We conclude that the most informative and straight-forward constraints on Q'* will be obtained by direct observational measurements of the shift in transit arrival times in individual hot Jupiter systems. We show that this is achievable across the mass spectrum of exoplanet host stars within a decade, and will directly probe the effects of stellar interior structure on tidal dissipation., 21 pages, 16 figures, 6 tables, accepted for publication in MNRAS
Published: 2021

11. Near-infrared observations of dusty white dwarfs

Author: Amy Bonsor, Ted von Hippel, Siyi Xu, Laura K. Rogers, Michael Jura, Kate Y. L. Su, and Simon Hodgkin
Subjects: Physics, 010504 meteorology & atmospheric sciences, Infrared, Scattering, Near-infrared spectroscopy, White dwarf, Astronomy and Astrophysics, Astrophysics, Planetary system, 01 natural sciences, Accretion (astrophysics), Space and Planetary Science, Asteroid, K band, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: AbstarctPlanetary material in the atmospheres of white dwarfs is thought to be scattered inwards from outer planetary systems. Dusty emission in the infrared traces the accretion. As the scattering of many small asteroids is a stochastic process, variability in the infrared emission is predicted. We report a 3 year near-infrared (J, H and K) monitoring campaign of 34 dusty, polluted white dwarfs which aims to search for dust emission variability. We find all white dwarfs have consistent near-infrared fluxes, implying the excess emission is stable. This suggests tidal disruption events which lead to large variabilities are rare and quick (K band data suggest a potential colour change associated with the dust emission that needs further confirmation.
Published: 2019
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12. Identification of Young Stellar Object candidates in the Gaia DR2 x AllWISE catalogue with machine learning methods

Author: E. Szegedi-Elek, E. Varga-Verebélyi, Róbert Beck, Ágnes Kóspál, Gábor Marton, Simon Hodgkin, Jozsef Varga, Cs. Kiss, Péter Ábrahám, M. Kun, and László Szabados
Subjects: Milky Way, Young stellar object, Population, FOS: Physical sciences, Magnitude (mathematics), Machine learning, computer.software_genre, Table (information), 01 natural sciences, 0103 physical sciences, education, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, education.field_of_study, 010308 nuclear & particles physics, business.industry, Astronomy and Astrophysics, Object (computer science), Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Artificial intelligence, Astrophysics - Instrumentation and Methods for Astrophysics, business, computer
Abstract: The second $Gaia$ Data Release (DR2) contains astrometric and photometric data for more than 1.6 billion objects with mean $Gaia$ $G$ magnitude $, Comment: 19 pages, 12 figures, 3 tables
Published: 2019
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13. Info for the Gaia Catalogue of Nearby Stars

Author: Richard Smart, Luis Sarro, Jan Rybizki, Celine Reyle, Annie Robin, Nigel Hambly, Ummi Abbas, Martin Barstow, Jos de Bruijne, Beatrice Bucciarelli, Josep Carrasco, William Cooper, Simon Hodgkin, Edargo Masana, Daniele Michalik, Johannes Sahlmann, Alessandro Sozzetti, Wolk, Scott, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Universidad Estatal a Distancia (UNED), Max Planck Institute for Astronomy (MPIA), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, University of Leicester, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), and European Space Astronomy Centre (ESAC)
Subjects: Very low mass stars, Cool Stars on the main sequence, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The Gaia Catlogue of Nearby Stars is a catalogue of 331,312 objectsthat contains at least 92% of stars of stellar type M9 within 100pcof the Sun. We estimate that 9% of the stars in this catalogueprobably lie outside 100, pc, but when the distance probability function is used, a correct treatment of this contamination ispossible. We produced luminosity functions with a highsignal-to-noise ratio for the main-sequence stars, giants, and whitedwarfs. We examine in detail the Hyades cluster, the white dwarf population, and wide-binary systems and produced candidate lists forall three samples. We detected local manifestations of severalstreams, superclusters, and halo objects, in which we identified 12members of the Gaia Enceladus. We present the first direct parallaxes offive objects in multiple systems within 10pc of the Sun. In this poster we provide links to the outreach materials, data access and discussion groups of the GCNS project. &nbsp
Published: 2021
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14. Assessing telluric correction methods for Na detections with high-resolution exoplanet transmission spectroscopy

Author: Samuel H. C. Cabot, Simon Hodgkin, Nikku Madhusudhan, Adam B Langeveld, Nikku, Madhusudhan [0000-0002-4869-000X], and Apollo - University of Cambridge Repository
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Photosphere, 010308 nuclear & particles physics, FOS: Physical sciences, Telluric contamination, Astronomy and Astrophysics, Astrophysics, Atmospheric model, 01 natural sciences, Spectral line, Exoplanet, Space and Planetary Science, astro-ph.EP, 0103 physical sciences, Hot Jupiter, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Spectrograph, astro-ph.IM, Line (formation), Astrophysics - Earth and Planetary Astrophysics
Abstract: Using high-resolution ground-based transmission spectroscopy to probe exoplanetary atmospheres is difficult due to the inherent telluric contamination from absorption in Earth's atmosphere. A variety of methods have previously been used to remove telluric features in the optical regime and calculate the planetary transmission spectrum. In this paper we present and compare two such methods, specifically focusing on Na detections using high-resolution optical transmission spectra: (1) calculating the telluric absorption empirically based on the airmass, and (2) using a model of the Earth's transmission spectrum. We test these methods on the transmission spectrum of the hot Jupiter HD 189733 b using archival data obtained with the HARPS spectrograph during three transits. Using models for Centre-to-Limb Variation and the Rossiter-McLaughlin effect, spurious signals which are imprinted within the transmission spectrum are reduced. We find that correcting tellurics with an atmospheric model of the Earth is more robust and produces consistent results when applied to data from different nights with changing atmospheric conditions. We confirm the detection of sodium in the atmosphere of HD 189733 b, with doublet line contrasts of -0.64 $\pm$ 0.07 % (D2) and -0.53 $\pm$ 0.07 % (D1). The average line contrast corresponds to an effective photosphere in the Na line located around 1.13 R$_p$. We also confirm an overall blueshift of the line centroids corresponding to net atmospheric eastward winds with a speed of 1.8 $\pm$ 1.2 km/s. Our study highlights the importance of accurate telluric removal for consistent and reliable characterisation of exoplanetary atmospheres using high-resolution transmission spectroscopy., Published in MNRAS, 13 pages, 9 figures. Updated with proof corrections
Published: 2021

15. Gaia Early Data Release 3: Gaia photometric science alerts

Author: Gerry Gilmore, F. De Angeli, David Alexander Kann, Richard Wilson, Danny Steeghs, Cs. Kiss, Łukasz Wyrzykowski, S. Komossa, L. Palaversa, Ulrich Kolb, S. van Velzen, L. Tomasella, L. Eyer, Ágnes Kóspál, Axel Schwope, A. Yoldas, D. Padeletti, G. Kovács, N. Schartel, Christopher J. Davis, Laszlo Szabados, M. L. Pretorius, M. Fridman, J. M. Carrasco, D. L. Harrison, N. Blagorodnova, A. Hourihane, W. van Reeven, Morgan Fraser, P. Tisserand, D. W. Evans, G. Holland, P. J. Richards, K. Kruszyńska, Nicholas Rowell, Z. Nagy, Elmé Breedt, J. H. J. de Bruijne, Sergey E. Koposov, Mária Kun, M. van Leeuwen, Timothy Butterley, Christian Knigge, G. Busso, F. van Leeuwen, Martin Dominik, A. Gomboc, J. Castañeda, S. J. Smartt, J. Japelj, N. Ihanec, Simon Hodgkin, N. Garralda, Carole Mundell, A. A. Mahabal, S. G. Baker, S. P. Littlefair, J. S. Clark, P. T. O'Brien, Michael Davidson, Brigitta Sipőcz, Maroussia Roelens, Gisella Clementini, Thomas Wevers, Alexander Scholz, Giuseppe Leto, Peter G. Jonker, A. Delgado, P. Ábrahám, B. Holl, George M. Seabroke, Gábor Marton, N. A. Walton, C. Diener, G. Altavilla, Patricia A. Whitelock, Valério A. R. M. Ribeiro, Goran Damljanović, P. Burgess, D. R. Young, M. Riello, P. Osborne, Claus Fabricius, Nigel Hambly, Michael D. Smith, Mark Sullivan, D. Eappachen, A. G. A. Brown, Krzysztof A. Rybicki, H. Campbell, Raphael Guerra, Timo Prusti, J. J. González-Vidal, I. Serraller, Andrzej Pigulski, Fraser Lewis, Dirk Froebrich, V. S. Dhillon, Mark Cropper, Z. Kostrzewa-Rutkowska, Chris M. Copperwheat, Jordi Portell, Ulrich Bastian, L. K. Hardy, Michel Dennefeld, P. Esquej, E. Szegedi-Elek, Guy Rixon, Francois Mignard, C. Dolding, S. Cowell, Science and Technology Facilities Council (UK), European Research Council, European Commission, Slovenian Research Agency, Leverhulme Trust, Agenzia Spaziale Italiana, Ministry of Education, Science and Technological Development (Serbia), Netherlands Organization for Scientific Research, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
Subjects: media_common.quotation_subject, Astronomy, Stars: variables: general, general [Supernovae], Supernovae: general, Astrophysics, Surveys, 7. Clean energy, variables: general [Stars], Variables, variable: general [Stars], QB Astronomy, General, Quasars, QC, QB, media_common, Physics, Kiss, Astronomy and Astrophysics, general [Quasars], 3rd-DAS, Creative commons, Stars, Quasars: general, QC Physics, Supernovae, 13. Climate action, Space and Planetary Science, Instrumentation and Methods for Astrophysics, Astronomical instrumentation, methods and techniques, Humanities, Data release
Abstract: Full list of authors: Hodgkin, S. T.; Harrison, D. L.; Breedt, E.; Wevers, T.; Rixon, G.; Delgado, A.; Yoldas, A.; Kostrzewa-Rutkowska, Z.; Wyrzykowski, Ł.; van Leeuwen, M.; Blagorodnova, N.; Campbell, H.; Eappachen, D.; Fraser, M.; Ihanec, N.; Koposov, S. E.; Kruszyńska, K.; Marton, G.; Rybicki, K. A.; Brown, A. G. A.; Burgess, P. W.; Busso, G.; Cowell, S.; De Angeli, F.; Diener, C.; Evans, D. W.; Gilmore, G.; Holland, G.; Jonker, P. G.; van Leeuwen, F.; Mignard, F.; Osborne, P. J.; Portell, J.; Prusti, T.; Richards, P. J.; Riello, M.; Seabroke, G. M.; Walton, N. A.; Ábrahám, P.; Altavilla, G.; Baker, S. G.; Bastian, U.; O'Brien, P.; de Bruijne, J.; Butterley, T.; Carrasco, J. M.; Castañeda, J.; Clark, J. S.; Clementini, G.; Copperwheat, C. M.; Cropper, M.; Damljanovic, G.; Davidson, M.; Davis, C. J.; Dennefeld, M.; Dhillon, V. S.; Dolding, C.; Dominik, M.; Esquej, P.; Eyer, L.; Fabricius, C.; Fridman, M.; Froebrich, D.; Garralda, N.; Gomboc, A.; González-Vidal, J. J.; Guerra, R.; Hambly, N. C.; Hardy, L. K.; Holl, B.; Hourihane, A.; Japelj, J.; Kann, D. A.; Kiss, C.; Knigge, C.; Kolb, U.; Komossa, S.; Kóspál, Á.; Kovács, G.; Kun, M.; Leto, G.; Lewis, F.; Littlefair, S. P.; Mahabal, A. A.; Mundell, C. G.; Nagy, Z.; Padeletti, D.; Palaversa, L.; Pigulski, A.; Pretorius, M. L.; van Reeven, W.; Ribeiro, V. A. R. M.; Roelens, M.; Rowell, N.; Schartel, N.; Scholz, A.; Schwope, A.; Sipőcz, B. M.; Smartt, S. J.; Smith, M. D.; Serraller, I.; Steeghs, D.; Sullivan, M.; Szabados, L.; Szegedi-Elek, E.; Tisserand, P.; Tomasella, L.; van Velzen, S.; Whitelock, P. A.; Wilson, R. W.; Young, D. R.-- This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., Context. Since July 2014, the Gaia mission has been engaged in a high-spatial-resolution, time-resolved, precise, accurate astrometric, and photometric survey of the entire sky. Aims. We present the Gaia Science Alerts project, which has been in operation since 1 June 2016. We describe the system which has been developed to enable the discovery and publication of transient photometric events as seen by Gaia. Methods. We outline the data handling, timings, and performances, and we describe the transient detection algorithms and filtering procedures needed to manage the high false alarm rate. We identify two classes of events: (1) sources which are new to Gaia and (2) Gaia sources which have undergone a significant brightening or fading. Validation of the Gaia transit astrometry and photometry was performed, followed by testing of the source environment to minimise contamination from Solar System objects, bright stars, and fainter near-neighbours. Results. We show that the Gaia Science Alerts project suffers from very low contamination, that is there are very few false-positives. We find that the external completeness for supernovae, CE = 0.46, is dominated by the Gaia scanning law and the requirement of detections from both fields-of-view. Where we have two or more scans the internal completeness is CI = 0.79 at 3 arcsec or larger from the centres of galaxies, but it drops closer in, especially within 1 arcsec. Conclusions. The per-Transit photometry for Gaia transients is precise to 1% at G = 13, and 3% at G = 19. The per-Transit astrometry is accurate to 55 mas when compared to Gaia DR2. The Gaia Science Alerts project is one of the most homogeneous and productive transient surveys in operation, and it is the only survey which covers the whole sky at high spatial resolution (subarcsecond), including the Galactic plane and bulge. © S. T. Hodgkin et al. 2021., This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. Further details of funding authorities and individuals contributing to the success of the mission is shown at https://gea.esac.esa.int/archive/documentation/GEDR3/Miscellaneous/sec_acknowl/. We thank the United Kingdom Particle Physics and Astronomy Research Council (PPARC), the United Kingdom Science and Technology Facilities Council (STFC), and the United Kingdom Space Agency (UKSA) through the following grants to the University of Bristol, the University of Cambridge, the University of Edinburgh, the University of Leicester, the Mullard Space Sciences Laboratory of University College London, and the United Kingdom Rutherford Appleton Laboratory (RAL): PP/D006511/1, PP/D006546/1, PP/D006570/1, ST/I000852/1, ST/J005045/1, ST/K00056X/1, ST/K000209/1, ST/K000756/1, ST/L006561/1, ST/N000595/1, ST/S000623/1, ST/N000641/1, ST/N000978/1, ST/N001117/1, ST/S000089/1, ST/S000976/1, ST/S001123/1, ST/S001948/1, ST/S002103/1, and ST/V000969/1. This paper made use of the Whole Sky Database (WSDB) created by Sergey Koposov and maintained at the Institute of Astronomy, Cambridge with financial support from the Science and Technology Facilities Council (STFC) and the European Research Council (ERC). We thank the William Herschel and Isaac Newton Telescopes on the Roque de los Muchachos Observatory, La Palma, Spain, as well as the Optical Infrared Coordination Network for Astronomy (OPTICON) for their support of this project through telescope time, especially during the commissioning and verification phases. We thank the Copernico 1.82 m telescope (Mt. Ekar, Asiago Italy) operated by INAF Padova for supporting the project through telescope time (under the Large Programme Tomasella-SNe) during the verification phases. We acknowledge observations taken as part of the PESSTO project collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 199.D-0143. Authors at the ICCUB were supported by the Spanish Ministry of Science, Innovation and University (MICIU/FEDER, UE) through grant RTI2018-095076-B-C21, and the Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia ’María de Maeztu’) through grant CEX2019-000918-M. This work is supported by Polish NCN grants: Daina No. 2017/27/L/ST9/03221, Harmonia No. 2018/30/M/ST9/00311, Preludium No. 2017/25/N/ST9/01253 and MNiSW grant DIR/WK/2018/12 as well as the European Commission’s Horizon2020 OPTICON grant No. 730890. The Authors would like to thank the Warsaw University OGLE project for their continuous support in this work. AB acknowledges financial support from the Netherlands Research School for Astronomy (NOVA). AG acknowledges the financial support from the Slovenian Research Agency (grants P1-0031, I0-0033, J1-8136, J1-2460). AH was funded in part by the Leverhulme Trust through grant RPG-2012-541 and by the European Research Council grant 320360. AP acknowledges support from the NCN grant no. 2016/21/B/ST9/01126. CM acknowledges support from Jim and Hiroko Sherwin. DAK acknowledges support from the Spanish research projects AYA 2014-58381-P, AYA2017-89384-P, from Juan de la Cierva Incorporación fellowship IJCI-2015-26153, and from Spanish National Research Project RTI2018-098104-J-I00 (GRBPhot). EB and STH are funded by the Science and Technology Facilities Council grant ST/S000623/1. TW was funded in part by European Research Council grant 320360 and by European Commission grant 730980. GC acknowledges the Agenzia Spaziale Italiana (ASI) for its continuing support through contract 2018-24-HH.0 to the Italian Istituto Nazionale di Astrofisica (INAF). GD acknowledges the observing grant support from the Institute of Astronomy and Rozhen NAO BAS through the bilateral joint research project “Gaia Celestial Reference Frame (CRF) and fast variable astronomical objects” (during 2020-2022, leader is G. Damljanovic), and support by the Ministry of Education, Science and Technological Development of the Republic of Serbia (contract no. 451-03-68/2020-14/200002). G. Marton acknowledges support from the EC Horizon 2020 project OPTICON (730890) and the ESA PRODEX contract no. 4000129910. MF is supported by a Royal Society - Science Foundation Ireland University Research Fellowship NB acknowledges support from the research programme VENI, with project number 016.192.277, which is (partly) financed by the Netherlands Organisation for Scientific Research (NWO). NI is partially supported by Polish NCN DAINA grant no. 2017/27/L/ST9/03221. PAW acknowledges research funding from the South African National Research Foundation. RWW was funded by the Science and Technology Facilities Council grant ST/P000541/1. V.A.R.M.R. acknowledges financial support from Radboud Excellence Initiative, the Fundação para a Ciência e a Tecnologia (FCT) in the form of an exploratory project of reference IF/00498/2015/CP1302/CT0001, FCT and the Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) through national funds and when applicable co-funded EU funds under the project UIDB/EEA/50008/2020, and supported by Enabling Green E-science for the Square Kilometre Array Research Infrastructure (ENGAGE-SKA), POCI-01-0145-FEDER-022217, and PHOBOS, POCI-01-0145-FEDER-029932, funded by Programa Operacional Competitividade e Internacionalização (COMPETE 2020) and FCT, Portugal. ZKR acknowledges funding from the Netherlands Research School for Astronomy (NOVA). ZN acknowledges support from the ESA PRODEX contract nr. 4000129910., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.
Published: 2021
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16. The Galactic Anticentre

Author: Vincenzo Ripepi, A. de Torres, Annie C. Robin, Mariateresa Crosta, C. Diener, L. Noval, Daniel Michalik, P. J. Richards, L. Karbevska, K. Kruszyńska, E. Fraile, André Moitinho, Michał Pawlak, P. Panuzzo, M. Riello, Benoit Carry, A. Yoldas, Harry Enke, N. Tonello, P. Gavras, M. Vaillant, Rosanna Sordo, E. del Pozo, Lorenzo Rimoldini, M. Bernet, G. Orrù, W. van Reeven, J. M. Martín-Fleitas, S. Diakite, P. Burgess, P. Osborne, Derek W. Morris, M. I. Carnerero, Amina Helmi, Mike Smith, Iain A. Steele, Alessandro Sozzetti, M. Kontizas, A. Sagristà Sellés, Roberto Molinaro, B. Holl, D. Baines, D. Molina, J. Fernández-Hernández, S. Marinoni, Michele Bellazzini, Maria Süveges, Teresa Antoja, D. Barbato, Uwe Lammers, Isabella Pagano, Davide Massari, G. Plum, P. Ramos, G. Jevardat de Fombelle, M. Biermann, C. Crowley, Mathias Schultheis, D. W. Evans, P. A. Palicio, Paolo Montegriffo, Ramachrisna Teixeira, R. Blomme, Elmé Breedt, T. A. Lister, F. A. Jansen, Ruth Carballo, Marcella Marconi, A. Abreu Aramburu, J. M. Carrasco, F. Royer, S. Accart, A. Burlacu, S. Regibo, Andrej Prsa, M. Sarasso, Nicolas Rambaux, A. F. Mulone, Ana Ulla, Eric Gosset, Alessandra Mastrobuono-Battisti, George M. Seabroke, H. E. Delgado, Federico Marocco, C. Nicolas, T. Lebzelter, Nami Mowlavi, C. Barache, Nicoletta Sanna, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Silvio Leccia, A. Jean-Antoine Piccolo, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, F. Figueras, G. Busso, C. Fabre, P. Di Matteo, F. Riclet, F. Solitro, Eric Slezak, N. Samaras, João Alves, Emese Plachy, Timo Prusti, F. van Leeuwen, J. Osinde, O. Marchal, M. Ajaj, C. Ducourant, Tatiana Muraveva, Shay Zucker, H. Steidelmüller, Alberto Riva, D. Semeux, N. Cheek, Laurent Galluccio, Martin A. Barstow, Alex Bombrun, S. Liao, M. van Leeuwen, R. E. de Souza, P. de Laverny, T. Roegiers, Paul J. McMillan, G. Holland, Alexey Mints, G. Giuffrida, L. M. Sarro, Juan Zorec, G. Sadowski, P. Yvard, Carme Jordi, J. L. Halbwachs, Laurent Chemin, Ludovic Delchambre, M. Garcia-Reinaldos, Ugo Becciani, Diego Bossini, Ángel Gómez, Sergi Blanco-Cuaresma, Rossella Cancelliere, C. Fabricius, J. De Ridder, L. Eyer, L. Pulone, Simon Hodgkin, Ennio Poretti, F. De Angeli, M. Haywood, E. Anglada Varela, Antonella Vallenari, F. X. Pineau, D. Garabato, A. Guerrier, H. E. P. Lindstrøm, Thomas Hilger, I. Bellas-Velidis, Frédéric Arenou, Paolo Giacobbe, Ilaria Musella, Tristan Cantat-Gaudin, L. Palaversa, Pedro García-Lario, David Hobbs, C. Turon, E. Balbinot, P. de Teodoro, Sébastien Lambert, D. Katz, Angela Bragaglia, Anthony G. A. Brown, Paolo Tanga, P. Castro Sampol, J. C. Segovia, Alejandra Recio-Blanco, Yves Fremat, Jon Marchant, Jose M Hernandez, S. Ragaini, Sofia Randich, P. Re Fiorentin, J. F. Le Campion, Gisella Clementini, M. Segol, P. David, R. Drimmel, F. Crifo, J. Guiraud, M. David, R. L. Smart, M. Fabrizio, I. Gonzalez-Santamaria, D. Eappachen, M. G. Lattanzi, Miguel García-Torres, Andreas Korn, S. Voutsinas, László Molnár, Simchon Faigler, A. Mora, Nicholas Rowell, Antti Penttilä, R. Geyer, Sanjeev Khanna, Aldo Dell'Oro, H. E. Huckle, C. Dolding, N. Leclerc, Monica Rainer, R. Mor, J. Bakker, Maroussia Roelens, Douglas J. Marshall, A. G. Butkevich, Nigel Hambly, A. Masip, Laia Casamiquela, R. Messineo, Martin Altmann, A. M. Piersimoni, Alessandro Spagna, Gerry Gilmore, Stefano Bertone, Patrick Charlot, O. Vanel, Daniel Hestroffer, Marco Castellani, Sebastian L. Hidalgo, W. Roux, Łukasz Wyrzykowski, Krzysztof A. Rybicki, M. M. S. Marcos Santos, Raphael Guerra, Alberto Cellino, E. Poggio, Gérard Jasniewicz, J. J. González-Vidal, S. Cowell, Peter G. Jonker, C. M. Raiteri, S. Bartolomé, J. Álvarez Cid-Fuentes, Elisabetta Caffau, J. J. Aguado, N. R. Millar, Ulrike Heiter, Federica Spoto, Felix Franke, A. Baudesson-Stella, M. Barros, Tsevi Mazeh, A. Panahi, E. Brugaletta, R. Buzzi, Elena Pancino, G. Altavilla, E. Racero, Enrique Solano, Mikael Granvik, Minia Manteiga, C. Robin, Tomaz Zwitter, Deborah Busonero, Alberto Krone-Martins, Marc Audard, Kevin Benson, Christos Siopis, L. Balaguer-Núñez, C. A. L. Bailer-Jones, E. Poujoulet, O. L. Creevey, E. Szegedi-Elek, C. Fouron, Michael Davidson, E. Licata, Despina Hatzidimitriou, Mark Cropper, Z. Kostrzewa-Rutkowska, S. Managau, A. Dapergolas, Sergio Messina, Laszlo Szabados, H. I. Siddiqui, W. Löffler, Mario Gai, J.-B. Delisle, Leanne P. Guy, S. G. Baker, W. J. Cooper, Alfred Castro-Ginard, Conny Aerts, A. Lorca, Xavier Luri, Damien Ségransan, Grigori Fedorets, A. Garofalo, J. Juaristi Campillo, F. De Luise, F. Pailler, F. Taris, L. Bramante, Thierry Morel, T. Cornez, L. Martin Polo, M. Ramos-Lerate, Jordi Portell, E. Salguero, Sergei A. Klioner, K. Janßen, Ulrich Bastian, Stefan Jordan, P. Esquej, A. C. Lanzafame, Beatrice Bucciarelli, C. Panem, Y. Lebreton, Carlos Dafonte, S. Girona, D. Munoz, Dimitri Pourbaix, William Thuillot, J. H. J. de Bruijne, N. Brouillet, L. Chaoul, F. Torra, Alex Lobel, J.-L. Bassilana, Francesca Fragkoudi, M. Romero-Gómez, C. A. Stephenson, T. Pauwels, Eva Sciacca, Alessandro Bressan, Morgan Fouesneau, E. Livanou, E. Gerlach, X. Peñalosa Esteller, Roberto Morbidelli, L. Rohrbasser, Johannes Sahlmann, Elisa Distefano, P. Sartoretti, Karri Muinonen, Zoltan Balog, Y. Viala, J. Torra, H. Zhao, L. Siltala, G. Tauran, D. Souami, P. Madrero Pardo, David Teyssier, Jesus Salgado, J. Souchay, C. P. Murphy, Maria-Rosa L. Cioni, N. A. Walton, S. Bouquillon, Andrea Chiavassa, Agnes Fienga, Giovanni Comoretto, F. Julbe, A. Hutton, Yassine Damerdji, Richard I. Anderson, Pierre Fernique, Céline Reylé, M. Hauser, E. Utrilla, Pierre Kervella, C. Zurbach, Robert G. Mann, Ummi Abbas, Hector Canovas, D. L. Harrison, Y. Lasne, Mark Taylor, Y. Le Fustec, E. F. del Peloso, N. Bauchet, E. van Dillen, Jan Rybizki, N. Hładczuk, T. Boch, J. González-Núñez, Carine Babusiaux, C. Pagani, Krzysztof Nienartowicz, Eduard Masana, G. Kordopatis, N. Robichon, Luciana Bianchi, R. Gutiérrez-Sánchez, Arnaud Siebert, A. Kochoska, T. Carlucci, Jérôme Berthier, J. Castañeda, D. Vicente, R. De March, A. Garcia-Gutierrez, M. Weiler, F. Thévenin, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Guy Rixon, Francois Mignard, P. M. Marrese, M. A. Álvarez, Caroline Soubiran, Rene Andrae, C. Ordénovic, A. Delgado, V. Sanchez Gimenez, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Universidad de Barcelona, Xunta de Galicia, European Commission, Centros de Excelencia Severo Ochoa, BARCELONA SUPERCOMPUTING CENTER (BSC), SEV2015-0493, Krone Martins, A. [0000-0002-2308-6623], McMillan, P. [0000-0002-8861-2620], Carrasco Martínez, J. P. [0000-0002-3029-5853], Sozzetti, A. [0000-0002-7504-365X], Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MINECO/ICTI2013-2016/MDM-2014-0369, Centrode Excelencia Científica Instituto de Ciencias del Cosmos Universidad de Barcelona, MINECO/ICTI2013-2016/SEV2015-0493, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), National Natural Science Foundation of China (NSFC), Estonian Ministry of Education and Research, Centre National D'Etudes Spatiales (CNES), Agence Nationale de la Recherche (ANR), Centre National de la Recherche Scientifique (CNRS), European Commission (EC), European Research Council (ERC), Institut des Sciences de l'Univers (INSU), Institut National Polytechnique (INP), Institut National de Physique nucleaire et de Physique des Particules (IN2P3), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Hungarian Academy of Sciences, Hungarian National Research, Development, and Innovation Office (NKFIH), Science Foundation Ireland (SFI), Israel Science Foundation (ISF), Agenzia Spaziale Italiana (ASI), Italian Istituto Nazionale di Astrofisica (INAF), Netherlands Organisation for Scientific Research (NWO), Polish National Science Centre, Ministry of Science and Higher Education (MNiSW), Fundacao para a Ciencia e a Tecnologia (FCT), Slovenian Research Agency, Agencia Estatal de Investigación (AEI), Generalitat de Catalunya, United Kingdom Science and Technology Facilities Council (STFC), United Kingdom Space Agency (UKSA), Gaia Collaboration, Universidad de Cantabria, Astronomy, Kapteyn Astronomical Institute, Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), M2A 2021, 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)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Planetary-system research, Department of Physics, Particle Physics and Astrophysics, 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: trigonometric parallaxes, SOLAR NEIGHBORHOOD, Astronomy, SAGITTARIUS DWARF GALAXY, Astrophysics, 01 natural sciences, sagittarius dwarf galaxy, 010303 astronomy & astrophysics, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], solar neighborhood, Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, Gelexy: kinematics and dynamics, Kinematics and Dynamics, Open clusters and asssociations: individual: Berkeley 29, sky survey, Disk, Physical Sciences, kinematics and dynamics [Gelexy], old open clusters, MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, open clusters and associations: individual: Berkeley 29, Galaxy: kinematics and dynamics, disk [Galaxy], individual: Berkeley 29 [open clusters and associations], Astrometria, Berkeley 29, EXPLORING HALO SUBSTRUCTURE, LOCAL KINEMATICS, Milky Way, FOS: Physical sciences, Open Clusters and Associations, Individual, exploring halo substructure, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, Computer Science::Digital Libraries, stellar structure, Galaxy: disk, Open clusters and associations: individual: Saurer 1, Galactic halo, Halo, Settore FIS/05 - Astronomia e Astrofisica, individual: Berkeley 29 [Open clusters and asssociations], 0103 physical sciences, distances [stars], halo [Galaxy], Disc, Stars: distances, milky-way, Saurer 1, Astrophysics::Galaxy Astrophysics, canis-major, Science & Technology, 010308 nuclear & particles physics, TRIGONOMETRIC PARALLAXES, Galaxy: halo, stars: distances, open clusters and associations: individual: Saurer 1, Astrophysics - Astrophysics of Galaxies, Astronomy and Astrophysics, Galactic plane, kinematics and dynamics [Galaxy], 115 Astronomy, Space science, CANIS-MAJOR, Stars, Galaxy, Physics::History of Physics, Estels, individual: Saurer 1 [open clusters and associations], Distances, local kinematics, OLD OPEN CLUSTERS, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), SKY SURVEY, Open cluster, STELLAR STRUCTURE
Abstract: Aims. We aim to demonstrate the scientific potential of the Gaia Early Data Release 3 (EDR3) for the study of different aspects of the Milky Way structure and evolution and we provide, at the same time, a description of several practical aspects of the data and examples of their usage., Methods. We used astrometric positions, proper motions, parallaxes, and photometry from EDR3 to select different populations and components and to calculate the distances and velocities in the direction of the anticentre. In this direction, the Gaia astrometric data alone enable the calculation of the vertical and azimuthal velocities; also, the extinction is relatively low compared to other directions in the Galactic plane. We then explore the disturbances of the current disc, the spatial and kinematical distributions of early accreted versus in situ stars, the structures in the outer parts of the disc, and the orbits of open clusters Berkeley 29 and Saurer 1., Results. With the improved astrometry and photometry of EDR3, we find that: (i) the dynamics of the Galactic disc are very complex with oscillations in the median rotation and vertical velocities as a function of radius, vertical asymmetries, and new correlations, including a bimodality with disc stars with large angular momentum moving vertically upwards from below the plane, and disc stars with slightly lower angular momentum moving preferentially downwards; (ii) we resolve the kinematic substructure (diagonal ridges) in the outer parts of the disc for the first time; (iii) the red sequence that has been associated with the proto-Galactic disc that was present at the time of the merger with Gaia-Enceladus-Sausage is currently radially concentrated up to around 14 kpc, while the blue sequence that has been associated with debris of the satellite extends beyond that; (iv) there are density structures in the outer disc, both above and below the plane, most probably related to Monoceros, the Anticentre Stream, and TriAnd, for which the Gaia data allow an exhaustive selection of candidate member stars and dynamical study; and (v) the open clusters Berkeley 29 and Saurer 1, despite being located at large distances from the Galactic centre, are on nearly circular disc-like orbits., Conclusions. Even with our simple preliminary exploration of the Gaia EDR3, we demonstrate how, once again, these data from the European Space Agency are crucial for our understanding of the different pieces of our Galaxy and their connection to its global structure and history.
Published: 2021
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17. Dipper-like variability of the Gaia alerted young star V555 Ori

Author: László Mészáros, O. Hanyecz, Gabriella Zsidi, András Pál, Ádám Sódor, Elza Szegedi-Elek, Laszlo Szabados, D. Tarczay-Nehéz, Ágnes Kóspál, Simon Hodgkin, Péter Ábrahám, A. Ordasi, R. Szakats, Gábor Marton, A. Bódi, Csaba Kiss, R. Konyves-Toth, Mária Kun, A. Moór, L. Kriskovics, Zsófia Nagy, B. Ignácz, B. Cseh, Jerome Bouvier, Krisztián Vida, Zsófia Marianna Szabó, Anikó Farkas-Takács, Paula Sarkis, and Krisztián Sárneczky
Subjects: Physics, Brightness, Accretion (meteorology), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Extinction (astronomy), FOS: Physical sciences, Flux, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Light curve, 01 natural sciences, T Tauri star, Wavelength, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Variation (astronomy), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract: V555 Ori is a T Tauri star, whose 1.5 mag brightening was published as a Gaia science alert in 2017. We carried out optical and near-infrared photometric, and optical spectroscopic observations to understand the light variations. The light curves show that V555 Ori was faint before 2017, entered a high state for about a year, and returned to the faint state by mid-2018. In addition to the long-term flux evolution, quasi-periodic brightness oscillations were also evident, with a period of about 5 days. At optical wavelengths both the long-term and short-term variations exhibited colourless changes, while in the near-infrared they were consistent with changing extinction. We explain the brightness variations as the consequence of changing extinction. The object has a low accretion rate whose variation in itself would not be enough to reproduce the optical flux changes. This behaviour makes V555 Ori similar to the pre-main sequence star AA Tau, where the light changes are interpreted as periodic eclipses of the star by a rotating inner disc warp. The brightness maximum of V555 Ori was a moderately obscured ($A_V$=2.3 mag) state, while the extinction in the low state was $A_V$=6.4 mag. We found that while the Gaia alert hinted at an accretion burst, V555 Ori is a standard dipper, similar to the prototype AA Tau. However, unlike in AA Tau, the periodic behaviour was also detectable in the faint phase, implying that the inner disc warp remained stable in both the high and low states of the system., Accepted to MNRAS
Published: 2021
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18. Gaia early data release 3: summary of the contents and survey properties (Corrigendum)

Author: Mathias Schultheis, Marcella Marconi, N. Robichon, Luciana Bianchi, F. Crifo, J. Guiraud, D. Eappachen, R. Gutiérrez-Sánchez, Sanjeev Khanna, A. M. Piersimoni, Raphael Guerra, J. J. González-Vidal, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, Tristan Cantat-Gaudin, Alejandra Recio-Blanco, Ummi Abbas, Francesca Figueras, R. Blomme, Elmé Breedt, G. Busso, A. Jean-Antoine Piccolo, Gerry Gilmore, A. Panahi, S. Messina, C. Babusiaux, Łukasz Wyrzykowski, Mark Taylor, Alex Bombrun, M. Barros, M. Riello, M. Ajaj, C. Ducourant, Tatiana Muraveva, Alberto Cellino, E. Poggio, Y. Le Fustec, C. P. Murphy, Maria-Rosa L. Cioni, Hector Canovas, D. L. Harrison, Y. Lasne, Elena Pancino, N. Bauchet, G. Orrù, Sergi Blanco-Cuaresma, Simon Hodgkin, Ennio Poretti, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, Andrea Chiavassa, E. Szegedi-Elek, A. G. A. Brown, Laszlo Szabados, A. Masip, Laia Casamiquela, R. Messineo, C. Crowley, Alessandra Mastrobuono-Battisti, E. Poujoulet, Zoltan Balog, L. Eyer, A. Guerrier, H. E. P. Lindstrøm, Ilaria Musella, Laurent Galluccio, Martin A. Barstow, Aldo Dell'Oro, Mark Cropper, Z. Kostrzewa-Rutkowska, Angela Bragaglia, Arnaud Siebert, Damien Ségransan, A. Kochoska, J. L. Halbwachs, E. F. del Peloso, N. Hładczuk, F. Pailler, Stefan Jordan, Stefano Bertone, L. Pulone, Frédéric Arenou, Patrick Charlot, David Hobbs, P. Castro Sampol, Yves Fremat, Sofia Randich, Marc Audard, Despina Hatzidimitriou, A. Dapergolas, L. Palaversa, W. van Reeven, M. Hauser, E. Utrilla, Georges Kordopatis, Sergei A. Klioner, Alex Lobel, J.-L. Bassilana, G. Tauran, T. Prusti, H. Steidelmüller, Alberto Riva, Diego Bossini, Maria Süveges, Isabella Pagano, J. H. J. de Bruijne, Elisabetta Caffau, Federica Spoto, Felix Franke, T. Boch, M. I. Carnerero, T. Carlucci, Grigori Fedorets, J. Castañeda, W. Löffler, Enrique Solano, Paolo Montegriffo, A. Abreu Aramburu, T. Lebzelter, Nami Mowlavi, C. Barache, C. A. Stephenson, A. Lorca, L. Bramante, Amina Helmi, J.-B. Delisle, B. Holl, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, F. van Leeuwen, C. Robin, D. Katz, E. Gerlach, Elisa Distefano, Michele Bellazzini, P. de Laverny, G. Sadowski, Tomaz Zwitter, A. Burlacu, Teresa Antoja, Rossella Cancelliere, F. Torra, C. Pagani, Annie C. Robin, Johannes Sahlmann, Karri Muinonen, Eva Sciacca, D. Vicente, Krzysztof Nienartowicz, A. F. Mulone, Shay Zucker, Nicholas Rowell, H. E. Delgado, Dimitri Pourbaix, G. Giuffrida, H. E. Huckle, Federico Marocco, L. Noval, Daniel Michalik, P. J. Richards, Y. Viala, E. van Dillen, L. Karbevska, H. Zhao, L. Siltala, Nicoletta Sanna, K. Kruszyńska, E. Fraile, R. De March, Y. Lebreton, C. M. Raiteri, D. W. Evans, Ana Ulla, Francesca Fragkoudi, Jan Rybizki, E. Brugaletta, L. Rohrbasser, Andreas Korn, S. G. Baker, A. Garcia-Gutierrez, L. M. Sarro, R. Buzzi, T. Pauwels, Jérôme Berthier, L. Chaoul, W. J. Cooper, Eduard Masana, M. van Leeuwen, D. Garabato, P. Panuzzo, Maroussia Roelens, Benoit Carry, Deborah Busonero, Michael Davidson, J. González-Núñez, Thomas Hilger, E. Licata, M. Weiler, Mikael Granvik, Alessandro Bressan, Morgan Fouesneau, Miguel García-Torres, W. Roux, Pedro García-Lario, Iain A. Steele, P. Ramos, Alessandro Sozzetti, Roberto Molinaro, O. L. Creevey, D. Barbato, Lorenzo Rimoldini, Uwe Lammers, Alexey Mints, P. Sartoretti, E. Livanou, D. Souami, P. Madrero Pardo, David Teyssier, M. Bernet, Yassine Damerdji, X. Peñalosa Esteller, C. Fabre, F. Thévenin, Gérard Jasniewicz, Roberto Morbidelli, Jesus Salgado, Juan Zorec, Ángel Gómez, Douglas J. Marshall, A. G. Butkevich, M. Biermann, E. Racero, J. Torra, R. Gomel, O. Vanel, Daniel Hestroffer, Sebastian L. Hidalgo, P. A. Palicio, F. De Angeli, Richard L. Smart, J. M. Martín-Fleitas, Derek W. Morris, F. Royer, S. Diakite, S. Accart, C. Dolding, P. Burgess, Richard I. Anderson, A. Garofalo, I. Bellas-Velidis, George M. Seabroke, P. Osborne, Claus Fabricius, Jon Marchant, Ramachrisna Teixeira, João Alves, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Paolo Giacobbe, Emese Plachy, M. Fabrizio, I. Gonzalez-Santamaria, F. Taris, Kevin Benson, Christos Siopis, M. M. S. Marcos Santos, S. Cowell, Jose M Hernandez, S. Ragaini, Jordi Portell, Linda K. Molnar, R. Drimmel, Pierre Kervella, C. Zurbach, S. Bartolomé, J. Álvarez Cid-Fuentes, E. Salguero, Ulrich Bastian, Robert G. Mann, Marco Castellani, J. Osinde, E. Balbinot, Caroline Soubiran, Rene Andrae, J. Souchay, M. G. Lattanzi, S. Voutsinas, Agnes Fienga, Giovanni Comoretto, P. Esquej, A. C. Lanzafame, Beatrice Bucciarelli, C. Panem, Carlos Dafonte, Alfred Castro-Ginard, J. C. Segovia, Monica Rainer, F. Julbe, A. Hutton, Peter G. Jonker, William Thuillot, A. de Torres, F. De Luise, Pierre Fernique, Céline Reylé, M. Kontizas, G. Plum, Martin Altmann, L. Martin Polo, M. Ramos-Lerate, P. de Teodoro, Sébastien Lambert, G. Altavilla, André Moitinho, D. Munoz, N. Brouillet, Alessandro Spagna, C. Ordénovic, Gisella Clementini, C. Nicolas, Michał Pawlak, Silvio Leccia, A. Delgado, M. Romero-Gómez, N. Cheek, A. Yoldas, Harry Enke, Rosanna Sordo, V. Sanchez Gimenez, Mike Smith, P. David, D. Baines, Paolo Tanga, Guy Rixon, Alberto Krone-Martins, S. Managau, N. A. Walton, S. Bouquillon, C. Fouron, Francois Mignard, Xavier Luri, J. Juaristi Campillo, S. Girona, Thierry Morel, T. Cornez, P. M. Marrese, M. A. Álvarez, S. Liao, Andrej Prsa, M. Sarasso, Nicolas Rambaux, Paul J. McMillan, Ludovic Delchambre, M. Garcia-Reinaldos, M. Haywood, E. Anglada Varela, Antonella Vallenari, S. Regibo, R. E. de Souza, Sahar Shahaf, J. De Ridder, M. Segol, Simchon Faigler, A. Mora, Ulrike Heiter, Carla Cacciari, Minia Manteiga, H. I. Siddiqui, Mario Gai, Leanne P. Guy, N. Leclerc, T. A. Lister, F. A. Jansen, Ruth Carballo, J. M. Carrasco, Bengt Edvardsson, P. Di Matteo, K. Janßen, F. Riclet, F. Solitro, O. Marchal, G. Holland, F. X. Pineau, C. Turon, P. Re Fiorentin, Tsevi Mazeh, Mariateresa Crosta, C. Diener, J. F. Le Campion, Vincenzo Ripepi, M. David, R. Mor, N. Tonello, E. del Pozo, J. Bakker, Davide Massari, A. Sagristà Sellés, Marco Delbo, Eric Slezak, P. Gavras, N. Samaras, S. Marinoni, M. Vaillant, J. M. Petit, P. Yvard, Carme Jordi, Ugo Becciani, Antti Penttilä, R. Geyer, Nigel Hambly, Krzysztof A. Rybicki, L. Balaguer-Núñez, C. A. L. Bailer-Jones, Conny Aerts, Eric Gosset, D. Semeux, T. Roegiers, and Laurent Chemin
Subjects: Physics, Addenda, 010504 meteorology & atmospheric sciences, Errata, Parallaxes, Astronomy, Astronomy and Astrophysics, Astrophysics, Astrometry, Photometric, 01 natural sciences, Techniques, catalogs, astrometry, parallaxes, proper motions, techniques: photometric, errata, addenda, Settore FIS/05 - Astronomia e Astrofisica, Space and Planetary Science, 0103 physical sciences, Proper motions, Catalogs, 010303 astronomy & astrophysics, Data release, 0105 earth and related environmental sciences
Abstract: We present the early installment of the third Gaia data release, Gaia EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from Gaia DR2. Gaia EDR3 contains celestial positions and the apparent brightness in G for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (G_BP-G_RP) colour are also available. The passbands for G, G_BP, and G_RP are provided as part of the release. For ease of use, the 7 million radial velocities from Gaia DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of Gaia DR3. Finally, Gaia EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the Gaia-CRF3, which is based solely on extragalactic sources. The creation of the source list for Gaia EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for Gaia DR2, but it does feature new sources and there are some notable changes. The source list will not change for Gaia DR3. Gaia EDR3 represents a significant advance over Gaia DR2, with parallax precisions increased by 30 percent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30--40 percent for the parallaxes and by a factor ~2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for G, G_BP, and G_RP is valid over the entire magnitude and colour range, with no systematics above the 1 percent level.
Published: 2021

19. Infrared Excesses around Bright White Dwarfs from Gaia and unWISE. II

Author: Samuel Lai, Erik Dennihy, Siyi Xu, Atsuko Nitta, Scot Kleinman, S. K. Leggett, Amy Bonsor, Simon Hodgkin, Alberto Rebassa-Mansergas, Laura K. Rogers, Lai, S [0000-0001-9372-4611], Dennihy, E [0000-0003-2852-268X], Xu, S [0000-0002-8808-4282], Leggett, SK [0000-0002-3681-2989], Rebassa-Mansergas, A [0000-0002-6153-7173], Apollo - University of Cambridge Repository, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), University of Cambridge, Universitat Politècnica de Catalunya. Departament de Física, and Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica
Subjects: astro-ph.SR, Near infrared astronomy, FOS: Physical sciences, Astronomia Matèria fosca (Astronomia), Astrophysics::Cosmology and Extragalactic Astrophysics, Stellar accretion disks, Debris disks, Infrared astronomy, Astrophysics::Solar and Stellar Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Brown dwarfs, Astrophysics::Instrumentation and Methods for Astrophysics, White dwarfs, Astronomy and Astrophysics, Infrared excess, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Física::Astronomia i astrofísica [Àrees temàtiques de la UPC], astro-ph.EP, Astrophysics::Earth and Planetary Astrophysics, M dwarfs stars, White dwarf stars, Astrophysics - Earth and Planetary Astrophysics
Abstract: Infrared excesses around white dwarf stars indicate the presence of various astrophysical objects of interest, including companions and debris disks. In this second paper of a series, we present follow-up observations of infrared excess candidates from Gaia and unWISE discussed in the first paper, Paper I. We report space-based infrared photometry at 3.6 and 4.5 micron for 174 white dwarfs from the Spitzer Space Telescope and ground-based near-infrared J, H, and K photometry of 235 white dwarfs from Gemini Observatory with significant overlap between Spitzer and Gemini observations. These data are used to confirm or rule out the observed unWISE infrared excess. From the unWISE-selected candidate sample, the most promising infrared excess sample comes from both color and flux excess, which has a Spitzer confirmation rate of 95%. We also discuss a method to distinguish infrared excess caused by stellar or sub-stellar companions from potential dust disks. In total, we confirm the infrared excess around 62 white dwarfs, 10 of which are likely to be stellar companions. The remaining 52 bright white dwarfs with infrared excess beyond two microns has the potential to double the known sample of white dwarfs with dusty exoplanetary debris disks. Follow-up high-resolution spectroscopic studies of a fraction of confirmed excess white dwarfs in this sample have discovered emission from gaseous dust disks. Additional investigations will be able to expand the parameter space from which dust disks around white dwarfs are found., A.R.M. acknowledges financial support from the MINECO under the Ramón y Cajal program (RYC-2016-20254), the MINECO grant AYA2017-86274-P and the AGAUR grant SGR-661/2017. L.K.R. is grateful to STFC and the Institute of Astronomy, University of Cambridge for funding her PhD studentship
Published: 2021

20. Unresolved stellar companions with Gaia DR2 astrometry

Author: Zephyr Penoyre, Anthony G. A. Brown, Robert G. Izzard, G. Iorio, Christopher A. Tout, Simon Hodgkin, N. Wyn Evans, Cathie J. Clarke, Vasily Belokurov, Semyeong Oh, Andrew Everall, Sergey E. Koposov, Belokurov, Vasily [0000-0002-0038-9584], Evans, Wyn [0000-0002-5981-7360], Tout, Christopher [0000-0002-1556-9449], Clarke, Catherine [0000-0003-4288-0248], and Apollo - University of Cambridge Repository
Subjects: Stellar mass, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Blue straggler, 0103 physical sciences, Hot Jupiter, Astrophysics::Solar and Stellar Astrophysics, stars: evolution, 010303 astronomy & astrophysics, stars: general, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Binaries: General, Stars: Evolution, Stars: General, 010308 nuclear & particles physics, White dwarf, Astronomy and Astrophysics, Astrometry, Mass ratio, Horizontal branch, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, binaries: general, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract: For stars with unresolved companions, motions of the centre of light and that of mass decouple, causing a single-source astrometric model to perform poorly. We show that such stars can be easily detected with the reduced chi2 statistic, or RUWE, provided as part of Gaia DR2. We convert RUWE into the amplitude of the image centroid wobble, which, if scaled by the source distance, is proportional to the physical separation between companions (for periods up to several years). We test this idea on a sample of known spectroscopic binaries and demonstrate that the amplitude of the centroid perturbation scales with the binary period and the mass ratio as expected. We apply this technique to the Gaia DR2 data and show how the binary fraction evolves across the Hertzsprung--Russell diagram. The observed incidence of unresolved companions is high for massive young stars and drops steadily with stellar mass, reaching its lowest levels for white dwarfs. We highlight the elevated binary fraction for the nearby Blue Stragglers and Blue Horizontal Branch stars. We also illustrate how unresolved hierarchical triples inflate the relative velocity signal in wide binaries. Finally, we point out a hint of evidence for the existence of additional companions to the hosts of extrasolar hot jupiters., submitted to MNRAS, comments welcome
Published: 2020
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21. Gaia Early Data Release 3: Photometric content and validation

Author: G. Giuffrida, F. De Angeli, Carla Cacciari, G. Busso, Simon Hodgkin, S. Ragaini, L. Pulone, Anthony G. A. Brown, Nicholas A. Walton, D. W. Evans, D. L. Harrison, C. Diener, Marco Castellani, G. Holland, C. Fabricius, F. van Leeuwen, Paul W. Burgess, Nicoletta Sanna, M. Weiler, G. Altavilla, Nigel Hambly, S. Cowell, Gerard Gilmore, Michael Davidson, C. Pagani, F. De Luise, P. Osborne, S. Marinoni, A. M. Piersimoni, A. Yoldas, P. Montegriffo, L. Palaversa, Monica Rainer, Nicholas Rowell, Elena Pancino, P. J. Richards, Sebastian L. Hidalgo, Michele Bellazzini, Carme Jordi, J. M. Carrasco, M. Riello, Martin A. Barstow, Croatian Science Foundation, Agenzia Spaziale Italiana, Istituto Nazionale di Astrofisica, Ministerio de Ciencia, Innovación y Universidades (España), Particle Physics and Astronomy Research Council (UK), University of Bristol, UK Space Agency, University of Cambridge, University of Edinburgh, University of Leicester, University College London, Riello, Marco [0000-0002-3134-0935], Evans, Dafydd [0000-0002-6685-5998], Harrison, Diana [0000-0001-8687-6588], van Leeuwen, Floor [0000-0003-1781-4441], Gilmore, Gerard [0000-0003-4632-0213], Walton, Nicholas [0000-0003-3983-8778], and Apollo - University of Cambridge Repository
Subjects: FOS: Physical sciences, Context (language use), Astrophysics, Surveys, 7. Clean energy, 01 natural sciences, Instrumentation: photometers, Standard deviation, law.invention, Photometry (optics), law, 0103 physical sciences, Calibration, General, Galaxy: general, 010303 astronomy & astrophysics, Instrumentation, Instrumentation and Methods for Astrophysics (astro-ph.IM), general [Galaxy], Physics, Photometers, 010308 nuclear & particles physics, photometric [Techniques], Astronomy and Astrophysics, Astrometry, Photometer, Techniques, catalogs, surveys, instrumentation: photometers, techniques: photometric, Galaxy, photometers [Instrumentation], 13. Climate action, Space and Planetary Science, Magnitude (astronomy), Instrumentation and Methods for Astrophysics, Satellite, Catalogs, Astrophysics - Instrumentation and Methods for Astrophysics, Techniques: photometric, astro-ph.IM
Abstract: Riello, M., et al., [Context] Gaia Early Data Release 3 (Gaia EDR3) contains astrometry and photometry results for about 1.8 billion sources based on observations collected by the European Space Agency Gaia satellite during the first 34 months of its operational phase. [Aims] In this paper, we focus on the photometric content, describing the input data, the algorithms, the processing, and the validation of the results. Particular attention is given to the quality of the data and to a number of features that users may need to take into account to make the best use of the Gaia EDR3 catalogue. [Methods] The processing broadly followed the same procedure as for Gaia DR2, but with significant improvements in several aspects of the blue and red photometer (BP and RP) preprocessing and in the photometric calibration process. In particular, the treatment of the BP and RP background has been updated to include a better estimation of the local background, and the detection of crowding effects has been used to exclude affected data from the calibrations. The photometric calibration models have also been updated to account for flux loss over the whole magnitude range. Significant improvements in the modelling and calibration of the Gaia point and line spread functions have also helped to reduce a number of instrumental effects that were still present in DR2. Results. Gaia EDR3 contains 1.806 billion sources with G-band photometry and 1.540 billion sources with GBP and GRP photometry. The median uncertainty in the G-band photometry, as measured from the standard deviation of the internally calibrated mean photometry for a given source, is 0.2 mmag at magnitude G = 10-14, 0.8 mmag at G ≈ 17, and 2.6 mmag at G ≈ 19. The significant magnitude term found in the Gaia DR2 photometry is no longer visible, and overall there are no trends larger than 1 mmag mag-1. Using one passband over the whole colour and magnitude range leaves no systematics above the 1% level in magnitude in any of the bands, and a larger systematic is present for a very small sample of bright and blue sources. A detailed description of the residual systematic effects is provided. Overall the quality of the calibrated mean photometry in Gaia EDR3 is superior with respect to DR2 for all bands., The Gaia photometric data processing has been financially supported by (in alphabetical order by country): the Tenure Track Pilot Programme of the Croatian Science Foundation and the Ecole Polytechnique Fédérale de Lausanne and the Project TTP-2018-07-1171 Mining the Variable Sky, with funds of the Croatian-Swiss Research Programme; the Agenzia Spaziale Italiana (ASI) through contracts I/037/08/0, I/058/10/0, 2014-025-R.0, 2014-025-R.1.2015 and 2018-24-HH.0 to the Italian Istituto Nazionale di Astrofisica (INAF), and INAF; the Spanish Ministry of Science, Innovation and University (MICIU/FEDER, UE) through grants RTI2018-095076-B-C21, ESP2016-80079-C2-1-R, and the Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia “María de Maeztu”) through grants MDM-2014-0369 and CEX2019-000918-M; the United Kingdom Particle Physics and Astronomy Research Council (PPARC), the United Kingdom Science and Technology Facilities Council (STFC), and the United Kingdom Space Agency (UKSA) through the following grants to the University of Bristol, the University of Cambridge, the University of Edinburgh, the University of Leicester, the Mullard Space Sciences Laboratory of University College London, and the United Kingdom Rutherford Appleton Laboratory (RAL): PP/D006511/1, PP/D006546/1, PP/D006570/1, ST/I000852/1, ST/J005045/1, ST/K00056X/1, ST/K000209/1, ST/K000756/1, ST/L006561/1, ST/N000595/1, ST/N000641/1, ST/N000978/1, ST/N001117/1, ST/S000089/1, ST/S000976/1, ST/S001123/1, ST/S001948/1, ST/S002103/1, and ST/V000969/1.
Published: 2020
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22. Gaia Early Data Release 3: Acceleration of the solar system from Gaia astrometry

Author: Vincenzo Ripepi, P. Gavras, M. Vaillant, Mathias Schultheis, László Molnár, E. Poujoulet, Mark Cropper, C. Babusiaux, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, A. de Torres, Aldo Dell'Oro, J. Castañeda, Z. Kostrzewa-Rutkowska, A. Bombrun, André Moitinho, Marcella Marconi, Rossella Cancelliere, M. Hauser, M. Ajaj, C. M. Raiteri, L. Eyer, Michał Pawlak, H. I. Siddiqui, C. Ducourant, Tatiana Muraveva, Tsevi Mazeh, A. Panahi, Federico Marocco, Stefano Bertone, D. Vicente, Patrick Charlot, A. Guerrier, R. De March, Mario Gai, J. Souchay, H. E. P. Lindstrøm, Nicoletta Sanna, Agnes Fienga, Giovanni Comoretto, Jon Marchant, A. Lorca, E. Utrilla, A. Garcia-Gutierrez, Ilaria Musella, L. Balaguer-Núñez, Leanne P. Guy, N. Leclerc, E. Brugaletta, A. Yoldas, Harry Enke, Rosanna Sordo, Zoltan Balog, H. E. Huckle, L. Palaversa, Monica Rainer, T. A. Lister, F. A. Jansen, Ruth Carballo, Alessandro Spagna, J. M. Carrasco, Mikael Granvik, Derek W. Morris, F. Julbe, A. Hutton, J. Osinde, D. W. Evans, M. van Leeuwen, M. Weiler, F. Thévenin, F. Torra, Iain A. Steele, Lorenzo Rimoldini, Alessandro Sozzetti, Francesca Fragkoudi, K. Janßen, O. L. Creevey, J. González-Núñez, T. Pauwels, R. Buzzi, Miguel García-Torres, S. Liao, G. Tauran, Lennart Lindegren, C. Fouron, Pierre Fernique, Céline Reylé, P. Di Matteo, E. Szegedi-Elek, F. Pailler, Stefan Jordan, Roberto Molinaro, Elisabetta Caffau, Federica Spoto, Felix Franke, D. Barbato, Isabelle Lecoeur-Taïbi, Tristan Cantat-Gaudin, Alejandra Recio-Blanco, E. Livanou, W. Roux, X. Peñalosa Esteller, P. A. Palicio, J. H. J. de Bruijne, Sergi Blanco-Cuaresma, Deborah Busonero, F. Riclet, Conny Aerts, Georges Kordopatis, Guy Rixon, F. Solitro, Davide Massari, Mike Smith, D. Baines, Roberto Morbidelli, Gerry Gilmore, G. Plum, Alexey Mints, O. Marchal, Juan Zorec, Ángel Gómez, C. A. Stephenson, Michael Davidson, C. Fabricius, E. Licata, Sergio Messina, Laszlo Szabados, M. Biermann, A. Garofalo, G. Holland, F. De Angeli, Andreas Korn, E. Anglada Varela, Grigori Fedorets, S. Girona, E. Gerlach, Antonella Vallenari, M. Riello, Łukasz Wyrzykowski, Damien Ségransan, F. Taris, L. Bramante, Alberto Cellino, S. Regibo, Andrej Prsa, M. Sarasso, E. Poggio, W. Löffler, Paolo Giacobbe, Jordi Portell, Elisa Distefano, Eric Slezak, I. Bellas-Velidis, Nicolas Rambaux, E. Balbinot, J.-B. Delisle, Maroussia Roelens, E. Salguero, P. de Teodoro, E. van Dillen, Y. Lebreton, Francois Mignard, Sergei A. Klioner, Ulrich Bastian, N. Samaras, G. Orrù, R. E. de Souza, P. Esquej, Paul J. McMillan, A. C. Lanzafame, Sébastien Lambert, Beatrice Bucciarelli, Jose M Hernandez, M. Bernet, S. Ragaini, Gisella Clementini, A. F. Mulone, Ludovic Delchambre, C. Panem, Eric Gosset, P. David, M. Garcia-Reinaldos, Ana Ulla, F. Crifo, J. Guiraud, Mariateresa Crosta, L. Chaoul, C. Diener, Carlos Dafonte, Karri Muinonen, Alex Lobel, J.-L. Bassilana, Maria Süveges, Isabella Pagano, Dimitri Pourbaix, D. Eappachen, M. Haywood, R. Drimmel, Y. Viala, S. Voutsinas, D. Semeux, William Thuillot, N. A. Walton, Paolo Montegriffo, A. Abreu Aramburu, C. Fabre, H. Zhao, Alessandro Bressan, S. Bouquillon, Sanjeev Khanna, T. Lebzelter, N. Tonello, L. Siltala, M. G. Lattanzi, C. Crowley, P. Yvard, Carme Jordi, Elena Pancino, E. del Pozo, Jan Rybizki, Nami Mowlavi, C. Barache, Morgan Fouesneau, J. De Ridder, Ugo Becciani, Martin Altmann, F. van Leeuwen, P. M. Marrese, M. A. Álvarez, A. Jean-Antoine Piccolo, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, Caroline Soubiran, C. P. Murphy, A. M. Piersimoni, Alessandra Mastrobuono-Battisti, Peter G. Jonker, A. Sagristà Sellés, T. Roegiers, S. Marinoni, Johannes Sahlmann, Rene Andrae, P. Sartoretti, G. Altavilla, Raphael Guerra, F. X. Pineau, M. Segol, T. Prusti, J. J. González-Vidal, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, Andrea Chiavassa, Laurent Chemin, C. Turon, H. Steidelmüller, Douglas J. Marshall, A. G. Butkevich, Alberto Riva, P. de Laverny, Simchon Faigler, Laurent Galluccio, A. Mora, P. Re Fiorentin, C. Ordénovic, J. F. Le Campion, A. Delgado, V. Sanchez Gimenez, M. David, G. Sadowski, R. L. Smart, A. Masip, Laia Casamiquela, R. Messineo, R. Mor, J. Bakker, C. Dolding, J. M. Martín-Fleitas, S. Diakite, Coryn A. L. Bailer-Jones, D. Souami, P. Madrero Pardo, Martin A. Barstow, David Teyssier, Ummi Abbas, Jesus Salgado, Paolo Tanga, A. Burlacu, O. Vanel, Ulrike Heiter, Daniel Hestroffer, Sebastian L. Hidalgo, H. E. Delgado, Alberto Krone-Martins, C. Robin, Kevin Benson, Christos Siopis, S. Managau, P. Burgess, Tomaz Zwitter, M. M. S. Marcos Santos, S. Cowell, J. L. Halbwachs, Xavier Luri, Antti Penttilä, R. Geyer, Minia Manteiga, Yassine Damerdji, Nigel Hambly, S. Bartolomé, J. Álvarez Cid-Fuentes, P. Osborne, J. Juaristi Campillo, Mark Taylor, Richard I. Anderson, Y. Le Fustec, Thierry Morel, T. Cornez, Krzysztof A. Rybicki, L. Pulone, N. Bauchet, Pierre Kervella, C. Zurbach, Alfred Castro-Ginard, Frédéric Arenou, P. Ramos, Robert G. Mann, Annie C. Robin, J. C. Segovia, M. Barros, Hector Canovas, D. L. Harrison, Y. Lasne, L. Noval, David Hobbs, E. F. del Peloso, P. Castro Sampol, Yves Fremat, F. De Luise, Daniel Michalik, P. J. Richards, L. Karbevska, N. Hładczuk, K. Kruszyńska, T. Boch, Sofia Randich, A. G. A. Brown, C. Pagani, L. Martin Polo, M. Ramos-Lerate, Krzysztof Nienartowicz, Eduard Masana, E. Racero, E. Fraile, Marc Audard, N. Robichon, Luciana Bianchi, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Jérôme Berthier, Despina Hatzidimitriou, R. Gutiérrez-Sánchez, M. Fabrizio, I. Gonzalez-Santamaria, A. Dapergolas, P. Panuzzo, Benoit Carry, Francesca Figueras, R. Blomme, Elmé Breedt, D. Munoz, Diego Bossini, G. Busso, D. Katz, Simon Hodgkin, Ennio Poretti, N. Brouillet, Marco Castellani, Nicholas Rowell, Arnaud Siebert, M. Romero-Gómez, Shay Zucker, W. van Reeven, A. Kochoska, G. Giuffrida, Eva Sciacca, T. Carlucci, L. M. Sarro, M. I. Carnerero, Amina Helmi, D. Garabato, B. Holl, Michele Bellazzini, L. Rohrbasser, Teresa Antoja, J. Torra, Thomas Hilger, Pedro García-Lario, Gérard Jasniewicz, Enrique Solano, S. G. Baker, W. J. Cooper, F. Royer, S. Accart, George M. Seabroke, João Alves, Emese Plachy, C. Nicolas, Silvio Leccia, N. Cheek, Uwe Lammers, Ramachrisna Teixeira, Techniche Universtât Desden, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lund Observatory, Lund University [Lund], Zentrum für astronomie, Universität Heidelberg [Heidelberg], Department of nuclear medicine, Haukeland University Hospital, University of Bergen (UiB)-University of Bergen (UiB), Merck Serono S.A [Geneva Research Center], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), 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), Universität Heidelberg [Heidelberg] = Heidelberg University, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Planetary-system research, Department of Physics, Particle Physics and Astrophysics, Gaia Collaboration, Unidad de Excelencia Científica María de Maeztu Instituto de Ciencias del Cosmos Universidad de Barcelona, MDM-2014-0369, Centro de Excelencia Científica Severo Ochoa, Instituto de Ciencias del Cosmos de la Universidad de Barcelona, SEV2015-0493, Deliste, J. B. [0000-0001-5844-9888], Sozzeti, A. [0000-0002-7504-365X], Forderung der wissenschaftlichen Forschung (FWF), Belgian federal Science Policy Office (BELSPO), Hertha Firnberg Programme, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Comite Francais d'Evaluation de la Cooperation Universitaire et Scientifique avec le Bresil (COFECUB), National Natural Science Foundation of China (NSFC), China Scholarship Council (CSC), European Commission (EC), European Research Council (ERC), Hungarian National Research, Development, and Innovation Office (NKFIH), Science Foundation Ireland (SFI), Israel Science Foundation (ISF), Agenzia Spaziale Italiana (ASI), Istituto Nazionale di Astrofisica (INAF), Netherlands Research School for Astronomy (NOVA), Fundacao para a Ciencia e a Tecnologia (FCT), Agencia Estatal de Investigación (AEI), European Space Agency (ESA), Centre National D'Etudes Spatiales (CNES), Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR), Narodowe Centrum Nauki (NCN), Slovenian Research Agency, Swedish National Space Agency (SNSA), United Kingdom Science and Technology Facilities Council (STFC), Universitat de Barcelona (UB), Generalitat de Catalunya, Xunta de Galicia, Universidad de Cantabria, ITA, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Astronomy, and Kapteyn Astronomical Institute
Subjects: Data Analysis, Solar System, Astronomy, kinematics and dynamics, virgo cluster, Astrophysics, 01 natural sciences, bar, Astronomi, astrofysik och kosmologi, large-magellanic-cloud, Methods, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, Physics, Astrophysics of Galaxies, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, VIRGO CLUSTER, Kinematics and Dynamics, Amplitude, kinematics, Physical Sciences, MILKY-WAY, astrometry, Galaxy: kinematics and dynamics, PROPER MOTION, Proper motion, perturbation, proper motions, reference systems, methods: data analysis, Astrophysics - Astrophysics of Galaxies, FOS: Physical sciences, Context (language use), proper motion, Astronomy & Astrophysics, MASS, Computer Science::Digital Libraries, Gravitational potential, Acceleration, Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, data analysis [methods], Vector spherical harmonics, KINEMATICS, distance, milky-way, Science & Technology, PERTURBATION, 010308 nuclear & particles physics, Astronomy and Astrophysics, kinematics and dynamics [Galaxy], 115 Astronomy, Space science, Physics::History of Physics, BAR, Galaxy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), DISTANCE, mass, LARGE-MAGELLANIC-CLOUD
Abstract: Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions., Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar systembarycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution., Methods. Theeffect of the acceleration was obtained as a part of the general expansion of the vector field of proper motions in vector spherical harmonics (VSH). Various versions of the VSH fit and various subsets of the sources were tried and compared to get the most consistent result and a realistic estimate of its uncertainty. Additional tests with the Gaia astrometric solution were used to get a better idea of the possible systematic errors in the estimate., Results. Our best estimate of the acceleration based on Gaia EDR3 is (2.32 +/- 0.16) x 10(-10) m s(-2) (or 7.33 +/- 0.51 km s(-1) Myr-1) towards alpha = 269.1 degrees +/- 5.4 degrees, delta = -31.6 degrees +/- 4.1 degrees, corresponding to a proper motion amplitude of 5.05 +/- 0.35 mu as yr(-1). This is in good agreement with the acceleration expected from current models of the Galactic gravitational potential. We expect that future Gaia data releases will provide estimates of the acceleration with uncertainties substantially below 0.1 mu as yr(-1).
Published: 2020
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23. Electromagnetic counterparts to gravitational wave events from Gaia

Author: Peter G. Jonker, M. Riello, Sergey E. Koposov, D. W. Evans, F. De Angeli, M. van Leeuwen, Łukasz Wyrzykowski, P. Burgess, P. Osborne, Thomas Wevers, Z. Kostrzewa-Rutkowska, D. Eappachen, Guy Rixon, A. Delgado, A. Yoldas, D. L. Harrison, Elmé Breedt, Simon Hodgkin, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Koposov, S. E. [0000-0003-2644-135X], Harrison, D. [0000-0001-8687-6588], Wyrzykowski, L. [0000-0002-9658-6151], Koposov, S. [0000-0003-2644-135X], Breedt, E. [0000-0001-6180-3438], European Research Council (ERC), National Science Centre, Poland (NCN), European Commission (EC), National Aeronautics and Space Administration (NASA), Polish NCN HARMONIA, 2018/30/M/ST9/00311, European Commission Joint Research Centre, 730980, European Cooperation in Science and Technology (COST), CA18104, National Aeronautics & Space Administration (NASA), NNX08AR22G, National Science Foundation (NSF), AST-1238877, Harrison, Diana [0000-0001-8687-6588], Evans, Dafydd [0000-0002-6685-5998], Riello, Marco [0000-0002-3134-0935], and Apollo - University of Cambridge Repository
Subjects: transients, Astronomy, media_common.quotation_subject, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Surveys, Compact star, 01 natural sciences, 7. Clean energy, Gravitational waves, Transients, General Relativity and Quantum Cosmology, surveys, 0103 physical sciences, observational [Methods], High Energy Physics, 010306 general physics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, media_common, astro-ph.HE, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Gravitational wave, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Methods observational, LIGO, gravitational waves, Space and Planetary Science, Sky, methods: observational, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, astro-ph.IM
Abstract: The recent discoveries of gravitational wave events and in one case also its electromagnetic (EM) counterpart allow us to study the Universe in a novel way. The increased sensitivity of the LIGO and Virgo detectors has opened the possibility for regular detections of EM transient events from mergers of stellar remnants. Gravitational wave sources are expected to have sky localisation up to a few hundred square degrees, thus Gaia as an all-sky multi-epoch photometric survey has the potential to be a good tool to search for the EM counterparts. In this paper we study the possibility of detecting EM counterparts to gravitational wave sources using the Gaia Science Alerts system. We develop an extension to current used algorithms to find transients and test its capabilities in discovering candidate transients on a sample of events from the observation periods O1 and O2 of LIGO and Virgo. For the gravitational wave events from the current run O3 we expect that about 16 (25) per cent should fall in sky regions observed by Gaia 7 (10) days after gravitational wave. The new algorithm will provide about 10 candidates per day from the whole sky., Comment: MNRAS accepted, revised version with corrections from the erratum
Published: 2020
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24. Detection of secondary eclipses of WASP-10b and Qatar-1b in the Ks band and the correlation between Ks-band temperature and stellar activity

Author: Marcos P. Diaz, Jonathan J. Fortney, Mercedes Lopez-Morales, David Barrado, P. Cruz, Jayne Birkby, Jorge Lillo-Box, Simon Hodgkin, and Low Energy Astrophysics (API, FNWI)
Subjects: Physics, Brightness, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Astrophysics, Light curve, Occultation, Exoplanet, law.invention, Photometry (optics), Telescope, Theoretical physics, Space and Planetary Science, law, Brightness temperature, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Eclipse
Abstract: The Calar Alto Secondary Eclipse study was a program dedicated to observe secondary eclipses in the near-IR of two known close-orbiting exoplanets around K-dwarfs: WASP-10b and Qatar-1b. Such observations reveal hints on the orbital configuration of the system and on the thermal emission of the exoplanet, which allows the study of the brightness temperature of its atmosphere. The observations were performed at the Calar Alto Observatory (Spain). We used the OMEGA2000 instrument (Ks band) at the 3.5m telescope. The data was acquired with the telescope strongly defocused. The differential light curve was corrected from systematic effects using the Principal Component Analysis (PCA) technique. The final light curve was fitted using an occultation model to find the eclipse depth and a possible phase shift by performing a MCMC analysis. The observations have revealed a secondary eclipse of WASP-10b with depth of 0.137%, and a depth of 0.196% for Qatar-1b. The observed phase offset from expected mid-eclipse was of −0.0028 for WASP-10b, and of −0.0079 for Qatar-1b. These measured offsets led to a value for |ecosω| of 0.0044 for the WASP-10b system, leading to a derived eccentricity which was too small to be of any significance. For Qatar-1b, we have derived a |ecosω| of 0.0123, however, this last result needs to be confirmed with more data. The estimated Ks-band brightness temperatures are of 1647 K and 1885 K for WASP-10b and Qatar-1b, respectively. We also found an empirical correlation between the (R′HK) activity index of planet hosts and the Ks-band brightness temperature of exoplanets, considering a small number of systems.
Published: 2017
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25. Evidence for rapid disc formation and reprocessing in the X-ray bright tidal disruption event candidate AT 2018fyk

Author: Matt Nicholl, Marco Berton, Erkki Kankare, Mariusz Gromadzki, S. van Velzen, James Miller-Jones, Giorgos Leloudas, Z. Kostrzewa-Rutkowska, Łukasz Wyrzykowski, S. Moran, Francesca Onori, Peter G. Jonker, Simon Hodgkin, Kate Maguire, Seppo Mattila, Steve Schulze, Dheeraj R. Pasham, Thomas Wevers, University of Cambridge, Massachusetts Institute of Technology, University of Maryland, Baltimore, Technical University of Denmark, Weizmann Institute of Science, Curtin University, SRON Netherlands Institute for Space Research, Warsaw University, University of Turku, Metsähovi Radio Observatory, Trinity College Dublin, Istituto di Astrofisica e Planetologia Spaziali, University of Edinburgh, Aalto-yliopisto, and Aalto University
Subjects: 010504 meteorology & atmospheric sciences, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Population, black hole physics, Doubly ionized oxygen, nuclei [galaxies], FOS: Physical sciences, LINES, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, accretion, 0103 physical sciences, Emission spectrum, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, POPULATION, 0105 earth and related environmental sciences, Line (formation), High Energy Astrophysical Phenomena (astro-ph.HE), Physics, education.field_of_study, SPECTROSCOPY, Accretion (meteorology), BLACK-HOLE MASSES, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, accretion discs, Galaxy, galaxies [X-rays], GALAXIES, Stars, FE-II EMISSION, STELLAR, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), galaxies [ultraviolet], Astrophysics - High Energy Astrophysical Phenomena, FOLLOW-UP, ACCRETION DISC, STARS
Abstract: We present optical spectroscopic and Swift UVOT/XRT observations of the X-ray and UV/optical bright tidal disruption event (TDE) AT 2018fyk/ASASSN-18ul discovered by ASAS-SN. The Swift lightcurve is atypical for a TDE, entering a plateau after $\sim$40 days of decline from peak. After 80 days the UV/optical lightcurve breaks again to decline further, while the X-ray emission becomes brighter and harder. In addition to broad H, He and potentially O/Fe lines, narrow emission lines emerge in the optical spectra during the plateau phase. We identify both high ionisation (O III) and low ionisation (Fe II) lines, which are visible for $\sim$45 days. We similarly identify Fe II lines in optical spectra of ASASSN-15oi 330 d after discovery, indicating that a class of Fe-rich TDEs exists. The spectral similarity between AT 2018fyk, narrow-line Seyfert 1 galaxies and some extreme coronal line emitters suggests that TDEs are capable of creating similar physical conditions in the nuclei of galaxies. The Fe II lines can be associated with the formation of a compact accretion disk, as the emergence of low ionisation emission lines requires optically thick, high density gas. Taken together with the plateau in X-ray and UV/optical luminosity this indicates that emission from the central source is efficiently reprocessed into UV/optical wavelengths. Such a two-component lightcurve is very similar to that seen in the TDE candidate ASASSN-15lh, and is a natural consequence of a highly relativistic orbital pericenter., Version accepted for publication in MNRAS
Published: 2019
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26. NGTS-7Ab: An ultra-short period brown dwarf transiting a tidally-locked and active M dwarf

Author: Philipp Eigmüller, David R. Anderson, Michael R. Goad, J. Costes, Christopher A. Watson, Maximiliano Moyano, Dan Bayliss, I. P. Braker, Maximilian N. Günther, Jose I. Vines, Peter J. Wheatley, Claudia Belardi, Alexis M. S. Smith, Oliver Turner, Anders Erikson, Richard G. West, Stéphane Udry, James McCormac, Liam Raynard, Samuel Gill, Heike Rauer, Simon Hodgkin, Boris T. Gänsicke, Didier Queloz, Alexander Chaushev, Matthew R. Burleigh, James S. Jenkins, Sarah L. Casewell, Juan Cabrera, Edward Gillen, François Bouchy, Katja Poppenhaeger, James A. G. Jackman, Don Pollacco, Tom Louden, Edward M. Bryant, Louise D. Nielsen, Joshua T. Briegal, and Szilard Csizmadia
Subjects: Extrasolare Planeten und Atmosphären, Proper motion, Brown dwarf, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Star (graph theory), 01 natural sciences, stars: low-mass, stars: rotation, 0103 physical sciences, Phase relation, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), stars: individual: NGTS-7A, 010308 nuclear & particles physics, brown dwarfs [stars], Leitungsbereich PF, Astronomy and Astrophysics, Light curve, low mass [stars], Tidal locking, Orbit, individual: NGTS-7A [stars], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, rotation [stars], flare [stars], stars: flare, Astrophysics::Earth and Planetary Astrophysics, brown dwarfs, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present the discovery of NGTS-7Ab, a high mass brown dwarf transiting an M dwarf with a period of 16.2 hours, discovered as part of the Next Generation Transit Survey (NGTS). This is the shortest period transiting brown dwarf around a main or pre-main sequence star to date. The M star host (NGTS-7A) has an age of roughly 55 Myr and is in a state of spin-orbit synchronisation, which we attribute to tidal interaction with the brown dwarf acting to spin up the star. The host star is magnetically active and shows multiple flares across the NGTS and follow up lightcurves, which we use to probe the flare-starspot phase relation. The host star also has an M star companion at a separation of 1.13 arcseconds with very similar proper motion and systemic velocity, suggesting the NGTS-7 system is a hierarchical triple. The combination of tidal synchronisation and magnetic braking is expected to drive ongoing decay of the brown dwarf orbit, with a remaining lifetime of only 5-10 Myr., 21 pages, 16 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society
Published: 2019
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27. SPLOT: a snapshot survey for polarized light in optical transients

Author: Łukasz Wyrzykowski, Stefano Covino, Heloise F. Stevance, R. L. C. Starling, A. B. Higgins, Justyn R. Maund, Nial R. Tanvir, P. T. O'Brien, Klaas Wiersema, and Simon Hodgkin
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Faint Object Spectrograph, 010308 nuclear & particles physics, Polarimetry, FOS: Physical sciences, Astronomy and Astrophysics, Large Synoptic Survey Telescope, New Technology Telescope, Polarised light, 01 natural sciences, Supernova, Space and Planetary Science, 0103 physical sciences, Snapshot (computer storage), Blazar, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Remote sensing, QB
Abstract: We present SPLOT, a small scale pilot survey to test the potential of snapshot (single epoch) linear imaging polarimetry as a supplementary tool to traditional transient follow-up. Transients exist in a vast volume of observational parameter space and polarimetry has the potential to highlight sources of scientific interest and add value to near real-time transient survey streams. We observed a sample of $\sim 50$ randomly selected optical transients with the EFOSC2 and SofI instruments, on the 3.6m New Technology Telescope (NTT) to test the feasibility of the survey. Our sample contained a number of interesting individual sources: a variety of supernovae, X-ray binaries, a tidal disruption event, blazar outbursts, and, by design, numerous transients of unknown nature. We discuss the results, both for the individual sources and the survey in detail. We provide an overview on the success and limitations of SPLOT and also describe a novel calibration method for removing instrumental polarisation effects from Nasymth-mounted telescopes. We find that a SPLOT-like survey would be a benefit to the large scale future transient survey streams such as LSST. The polarimetric measurements have added scientific value to a significant number of the sources and, most importantly, has shown the potential to highlight unclassified transient sources of scientific interest for further study., Comment: Accepted in MNRAS. 20 pages, 10 figures, 3 tables. Also contains a 10 page, two part appendix with unpolarised standard star measurements used for calibration (A) and individual source information and light curves (B). Corrected more typos
Published: 2019

28. NGTS clusters survey. I. Rotation in the young benchmark open cluster Blanco 1

Author: Didier Queloz, Daniel Foreman-Mackey, Rosanna H. Tilbrook, Daniel Bayliss, Joshua T. Briegal, Matthew R. Burleigh, Floor van Leeuwen, Simon Hodgkin, James S. Jenkins, Alexis M. S. Smith, Christopher A. Watson, Richard G. West, Peter J. Wheatley, James McCormac, Liam Raynard, Sarah L. Casewell, Jose I. Vines, James A. G. Jackman, Claudia Belardi, Michael R. Goad, and Edward Gillen
Subjects: Rotation period, Extrasolare Planeten und Atmosphären, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Stellar classification, Rotation, 01 natural sciences, stars: rotation, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, open clusters and associations: individual: Blanco 1, 010303 astronomy & astrophysics, Stellar evolution, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Mass ratio, stars: variables: general, Stars, binaries: general, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Pleiades, Open cluster
Abstract: We determine rotation periods for 127 stars in the ~115 Myr old Blanco 1 open cluster using ~200 days of photometric monitoring with the Next Generation Transit Survey (NGTS). These stars span F5-M3 spectral types (1.2 $\gtrsim M \gtrsim$ 0.3 M$_{\odot}$) and increase the number of known rotation periods in Blanco 1 by a factor of four. We determine rotation periods using three methods: Gaussian process (GP) regression, generalised autocorrelation (G-ACF) and Lomb-Scargle (LS) periodograms, and find that GPs and G-ACF are more applicable to evolving spot modulation patterns. Between mid-F and mid-K spectral types, single stars follow a well-defined rotation sequence from ~2 to 10 days, whereas stars in photometric multiple systems typically rotate faster. This may suggest that the presence of a moderate-to-high mass ratio companion inhibits angular momentum loss mechanisms during the early pre-main sequence, and this signature has not been erased at ~100 Myr. The majority of mid-F to mid-K stars display evolving modulation patterns, whereas most M stars show stable modulation signals. This morphological change coincides with the shift from a well-defined rotation sequence (mid-F to mid-K stars) to a broad rotation period distribution (late-K and M stars). Finally, we compare our rotation results for Blanco 1 to the similarly-aged Pleiades: the single star populations in both clusters possess consistent rotation period distributions, which suggests that the angular momentum evolution of stars follows a well-defined pathway that is, at least for mid-F to mid-K stars, strongly imprinted by ~100 Myr., Comment: 19 pages, 14 figures, 2 tables, accepted for publication in MNRAS
Published: 2019
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29. NGTS-8b and NGTS-9b: two non-inflated hot-Jupiters

Author: James A. G. Jackman, Anders Erikson, I. P. Braker, M. G. Soto, Edward M. Bryant, Maximiliano Moyano, Joshua T. Briegal, Szilard Csizmadia, Michael R. Goad, Maximilian N. Günther, Didier Queloz, Claudia Belardi, Christopher A. Watson, Sarah L. Casewell, Jose I. Vines, Juan Cabrera, Oliver Turner, Richard G. West, James McCormac, J. Costes, Rosanna H. Tilbrook, Liam Raynard, François Bouchy, Simon Hodgkin, Samuel Gill, Heike Rauer, Edward Gillen, Matthew J. Hooton, Peter J. Wheatley, David R. Anderson, Daniel Bayliss, Philipp Eigmüller, Louise D. Nielsen, Alexis M. S. Smith, A. Thompson, Alexander Chaushev, Matthew R. Burleigh, James S. Jenkins, and Stéphane Udry
Subjects: Physics, Extrasolare Planeten und Atmosphären, Earth and Planetary Astrophysics (astro-ph.EP), stars: individual: NGTS-8 and NGTS-9 planetary systems, planets and satellites: detection, detection [planets and satellites], 010308 nuclear & particles physics, European research, Leitungsbereich PF, Library science, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, photometric [techniques], techniques: photometric, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Research council, 0103 physical sciences, individual: NGTS-8 and NGTS-9 planetary systems [stars], 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery, by the Next Generation Transit Survey (NGTS), of two hot-Jupiters NGTS-8b and NGTS-9b. These orbit a V = 13.68 K0V star (Teff = 5241 +/- 50 K) with a period of 2.49970 days, and a V = 12.80 F8V star (Teff = 6330 +/- 130 K) in 4.43527 days, respectively. The transits were independently verified by follow-up photometric observations with the SAAO 1.0-m and Euler telescopes, and we report on the planetary parameters using HARPS, FEROS and CORALIE radial velocities. NGTS-8b has a mass, 0.93 +0.04 -0.03 MJ and a radius, 1.09 +/- 0.03 RJ similar to Jupiter, resulting in a density of 0.89 +0.08 -0.07 g cm-3. This is in contrast to NGTS-9b, which has a mass of 2.90 +/- 0.17 MJ and a radius of 1.07 +/- 0.06 RJ , resulting in a much greater density of 2.93 +0.53 -0.49 g cm-3. Statistically, the planetary parameters put both objects in the regime where they would be expected to exhibit larger than predicted radii. However, we find that their radii are in agreement with predictions by theoretical non-inflated models., Comment: 12 pages, 7 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society
Published: 2019
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30. Gaia18aen: First symbiotic star discovered by Gaia

Author: J. Kolgjini, Ulrich Kolb, Krystian Iłkiewicz, A. Simon, Andrew Norton, Fraser Lewis, P. Zielinski, Saran Poshyachinda, Cezary Galan, M. Greet, V. Reshetnyk, K. Kruszyńska, Jan Skowron, Łukasz Wyrzykowski, Simon Hodgkin, V. Godunova, Joanna Mikolajewska, M. Morrell, Daniel E. Reichart, Supachai Awiphan, J. Merc, Krzysztof A. Rybicki, and Mariusz Gromadzki
Subjects: Physics, 010308 nuclear & particles physics, Metallicity, FOS: Physical sciences, White dwarf, Astronomy and Astrophysics, Astrophysics, Orbital period, 01 natural sciences, Spectral line, Photometry (optics), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Symbiotic star, 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Besides the astrometric mission of the Gaia satellite, its repeated and high-precision measurements serve also as an all-sky photometric transient survey. The sudden brightenings of the sources are published as Gaia Photometric Science Alerts and are made publicly available allowing the community to photometrically and spectroscopically follow-up the object. The goal of this paper was to analyze the nature and derive the basic parameters of Gaia18aen, transient detected at the beginning of 2018. It coincides with the position of the emission line star WRAY 15-136. The brightening was classified as a "nova?" on the basis of subsequent spectroscopic observation. We have analyzed two spectra of Gaia18aen and collected the available photometry of the object covering the brightenings in 2018 and also the preceding and following periods of quiescence. Based on this observational data, we have derived the parameters of Gaia18aen and discussed the nature of the object. Gaia18aen is the first symbiotic star discovered by the Gaia satellite. The system is an S-type symbiotic star and consists of an M giant of a slightly super-solar metallicity, with Teff ~3500 K, a radius of ~230 R$\odot$, and a high luminosity L ~7400 L$\odot$. The hot component is a hot white dwarf. We tentatively determined the orbital period of the system ~487 days. The main outburst of Gaia18aen in 2018 was accompanied by a decrease in the temperature of the hot component. The first phase of the outburst was characterized by the high luminosity L ~27000 L$\odot$, which remained constant for about three weeks after the optical maximum, later followed by the gradual decline of luminosity and increase of temperature. Several re-brightenings have been detected on the timescales of hundreds of days., Comment: accepted for publication in Astronomy & Astrophysics; 10 pages, 10 figures, 5 tables
Published: 2020
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31. NGTS-4b: A sub-Neptune Transiting in the Desert

Author: Michaël Gillon, Anders Erikson, Benjamin F. Cooke, Alexis M. S. Smith, Sandrine Sohy, Y. Almleaky, Paul Chote, George W. King, Michael R. Goad, Christopher A. Watson, Szilard Csizmadia, Daniel Bayliss, Edward Gillen, Philipp Eigmüller, Juan Cabrera, Matthew R. Burleigh, Artem Burdanov, Simon R. Walker, François Bouchy, Oliver Turner, Richard G. West, James McCormac, Emma Longstaff, Laetitia Delrez, James S. Jenkins, Boris T. Gänsicke, Claudia Belardi, Simon Hodgkin, Peter J. Wheatley, M. Soto, Maximilian N. Günther, Liam Raynard, M. Moyano, Alexander Chaushev, Stéphane Udry, Didier Queloz, David J. Armstrong, E. Foxell, Heike Rauer, Samantha Thompson, Sarah L. Casewell, Bruno Chazelas, Joshua T. Briegal, Louise D. Nielsen, C. Murray, Elsa Ducrot, Emmanuel Jehin, Tom Louden, James A. G. Jackman, Don Pollacco, Gregory Lambert, Gillen, Edward [0000-0003-2851-3070], Hodgkin, Simon [0000-0002-5470-3962], Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository
Subjects: Extrasolare Planeten und Atmosphären, planets and satellites: detection, detection [planets and satellites], FOS: Physical sciences, 01 natural sciences, photometric [techniques], techniques: photometric, photometric, stars: individual: NGTS-4- planetary systems, satellites, planets, Neptune, Planet, stars: individual: NGTS-4 planetary systems, 0103 physical sciences, Transit (astronomy), 010303 astronomy & astrophysics, planetary systems, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, Leitungsbereich PF, Desert (particle physics), Astronomy, Astronomy and Astrophysics, NGTS-4, Radius, Planetary system, Orbit, individual: NGTS-4- planetary systems [stars], 13. Climate action, Space and Planetary Science, Magnitude (astronomy), Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34d orbit. NGTS-4b has a mass M=$20.6\pm3.0$M_E and radius R=$3.18\pm0.26$R_E, which places it well within the so-called "Neptunian Desert". The mean density of the planet ($3.45\pm0.95$g/cm^3) is consistent with a composition of 100% H$_2$O or a rocky core with a volatile envelope. NGTS-4b is likely to suffer significant mass loss due to relatively strong EUV/X-ray irradiation. Its survival in the Neptunian desert may be due to an unusually high core mass, or it may have avoided the most intense X-ray irradiation by migrating after the initial activity of its host star had subsided. With a transit depth of $0.13\pm0.02$%, NGTS-4b represents the shallowest transiting system ever discovered from the ground, and is the smallest planet discovered in a wide-field ground-based photometric survey., Submitted to MNRAS
Published: 2018
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32. NGTS-2b: An inflated hot-Jupiter transiting a bright F-dwarf

Author: Katja Poppenhaeger, Don Pollacco, Lionel Metrailler, Maximiliano Moyano, Matthew R. Burleigh, Richard Alexander, Bruno Chazelas, Benjamin F. Cooke, Alexander Chaushev, James S. Jenkins, Daniel Bayliss, Michael R. Goad, Didier Queloz, Philipp Eigmüller, Heike Rauer, Szilard Csizmadia, Simon Hodgkin, Anders Erikson, Grégory L'Ambert, Edward Gillen, Oliver Turner, Richard G. West, James McCormac, Liam Raynard, Barry Smalley, Joshua T. Briegal, Matthew J. Hooton, Simon R. Walker, Stéphane Udry, Andrew Grange, Maximilian N. Günther, Peter J. Wheatley, Alexis M. S. Smith, Boris T. Gänsicke, A. Thompson, Christopher A. Watson, Louise D. Nielsen, Roberto Raddi, Sarah L. Casewell, M. Soto, Tom Louden, A. M. Read, Juan Cabrera, François Bouchy, David J. Armstrong, Gillen, Edward [0000-0003-2851-3070], Hodgkin, Simon [0000-0002-5470-3962], Hooton, Matthew John [0000-0003-0030-332X], Queloz, Didier [0000-0002-3012-0316], and Apollo - University of Cambridge Repository
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: detection, detection [planets and satellites], Giant planet, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Exoplanet, Photometry (optics), Transmission spectroscopy, fundamental parameters [planets and satellites], Space and Planetary Science, Planet, planets and satellites: detection – planets and satellites: fundamental parameters, 0103 physical sciences, Hot Jupiter, QB460, 010306 general physics, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, Rapid rotation, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report the discovery of NGTS-2b, an inflated hot-Jupiter transiting a bright F5V star (2MASS J14202949-3112074; $T_{\rm eff}$=$6478^{+94}_{-89}$ K), discovered as part of the Next Generation Transit Survey (NGTS). The planet is in a P=4.51 day orbit with mass $0.74^{+0.13}_{-0.12}$ M$_{J}$, radius $1.595^{+0.047}_{-0.045}$ R$_{J}$ and density $0.226^{+0.040}_{-0.038}$ g cm$^{-3}$; therefore one of the lowest density exoplanets currently known. With a relatively deep 1.0% transit around a bright V=10.96 host star, NGTS-2b is a prime target for probing giant planet composition via atmospheric transmission spectroscopy. The rapid rotation ($vsin$i=$15.2\pm0.8$ km s$^{-1}$) also makes this system an excellent candidate for Rossiter-McLaughlin follow-up observations, to measure the sky-projected stellar obliquity. NGTS-2b was confirmed without the need for follow-up photometry, due to the high precision of the NGTS photometry., 12 pages, 8 figures, accepted for publication in MNRAS
Published: 2018
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33. Automatic vetting of planet candidates from ground based surveys: Machine learning with NGTS

Author: Maximilian N. Günther, Christopher A. Watson, Lionel Metrailler, Matthew R. Burleigh, Alexis M. S. Smith, James S. Jenkins, Don Pollacco, Sarah L. Casewell, Didier Queloz, Michael R. Goad, Stéphane Udry, Katja Poppenhaeger, Edward Gillen, Heike Rauer, Simon R. Walker, Tom Louden, Simon Hodgkin, Peter J. Wheatley, Daniel Bayliss, Philipp Eigmüller, Richard G. West, James McCormac, Liam Raynard, David J. Armstrong, and François Bouchy
Subjects: detection [planets and satellites], statistical [methods], FOS: Physical sciences, Machine learning, computer.software_genre, 01 natural sciences, QA76, Vetting, Robustness (computer science), Planet, 0103 physical sciences, False positive paradox, data analysis [methods], general [planets and satellites], Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, business.industry, Astronomy and Astrophysics, Planetary system, Exoplanet, Random forest, exoplanets, Space and Planetary Science, Survey data collection, Artificial intelligence, business, Astrophysics - Instrumentation and Methods for Astrophysics, computer, Astrophysics - Earth and Planetary Astrophysics
Abstract: State of the art exoplanet transit surveys are producing ever increasing quantities of data. To make the best use of this resource, in detecting interesting planetary systems or in determining accurate planetary population statistics, requires new automated methods. Here we describe a machine learning algorithm that forms an integral part of the pipeline for the NGTS transit survey, demonstrating the efficacy of machine learning in selecting planetary candidates from multi-night ground based survey data. Our method uses a combination of random forests and self-organising-maps to rank planetary candidates, achieving an AUC score of 97.6\% in ranking 12368 injected planets against 27496 false positives in the NGTS data. We build on past examples by using injected transit signals to form a training set, a necessary development for applying similar methods to upcoming surveys. We also make the \texttt{autovet} code used to implement the algorithm publicly accessible. \texttt{autovet} is designed to perform machine learned vetting of planetary candidates, and can utilise a variety of methods. The apparent robustness of machine learning techniques, whether on space-based or the qualitatively different ground-based data, highlights their importance to future surveys such as TESS and PLATO and the need to better understand their advantages and pitfalls in an exoplanetary context., Accepted for publication in MNRAS, 15 pages
Published: 2018
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34. The Next Generation Transit Survey (NGTS)

Author: Hugh P. Osborn, Louise D. Nielsen, Heike Rauer, Stéphane Udry, Christopher A. Watson, Francesca Faedi, Matthew R. Burleigh, Maximilian N. Günther, Richard G. West, James McCormac, Liam Raynard, Lionel Metrailler, Ruth Titz-Weider, Maximiliano Moyano, James S. Jenkins, Andrés Jordán, Sarah L. Casewell, Katja Poppenhaeger, David J. Armstrong, Roberto Raddi, Anders Erikson, Edward Gillen, M. Soto, James A. G. Jackman, Don Pollacco, Bruno Chazelas, Paul Chote, Simon Hodgkin, Gregory Lambert, Andrew Grange, Daniel Bayliss, Boris T. Gänsicke, Szilard Csizmadia, Joao Bento, Michael R. Goad, L. Genolet, E. Foxell, Alexis M. S. Smith, Tom Louden, Simon R. Walker, Peter J. Wheatley, Didier Queloz, Juan Cabrera, François Bouchy, Philipp Eigmüller, Alexander Chaushev, Queloz, Didier [0000-0002-3012-0316], Gillen, Edward [0000-0003-2851-3070], Hodgkin, Simon [0000-0002-5470-3962], and Apollo - University of Cambridge Repository
Subjects: planets and satellites: detection, FOS: Physical sciences, Field of view, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 7. Clean energy, techniques: photometric, surveys, Observatory, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, planetary systems, Astrophysics::Galaxy Astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, First light, Planetary system, Exoplanet, Stars, instrumentation: photometers, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, atmospheric effects, Astrophysics - Earth and Planetary Astrophysics
Abstract: We describe the Next Generation Transit Survey (NGTS), which is a ground-based project searching for transiting exoplanets orbiting bright stars. NGTS builds on the legacy of previous surveys, most notably WASP, and is designed to achieve higher photometric precision and hence find smaller planets than have previously been detected from the ground. It also operates in red light, maximising sensitivity to late K and early M dwarf stars. The survey specifications call for photometric precision of 0.1 per cent in red light over an instantaneous field of view of 100 square degrees, enabling the detection of Neptune-sized exoplanets around Sun-like stars and super-Earths around M dwarfs. The survey is carried out with a purpose-built facility at Cerro Paranal, Chile, which is the premier site of the European Southern Observatory (ESO). An array of twelve 20cm f/2.8 telescopes fitted with back-illuminated deep-depletion CCD cameras are used to survey fields intensively at intermediate Galactic latitudes. The instrument is also ideally suited to ground-based photometric follow-up of exoplanet candidates from space telescopes such as TESS, Gaia and PLATO. We present observations that combine precise autoguiding and the superb observing conditions at Paranal to provide routine photometric precision of 0.1 per cent in 1 hour for stars with I-band magnitudes brighter than 13. We describe the instrument and data analysis methods as well as the status of the survey, which achieved first light in 2015 and began full survey operations in 2016. NGTS data will be made publicly available through the ESO archive., 20 pages, 17 Figures, Accepted for publication in MNRAS
Published: 2018
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35. The fast transient sky with Gaia

Author: Guy Rixon, Gijs Nelemans, Floor van Leeuwen, Abdullah Yoldas, D. L. Harrison, Thomas Wevers, Peter G. Jonker, Z. Kostrzewa-Rutkowska, Simon Hodgkin, Maroussia Roelens, and Laurent Eyer
Subjects: Brightness, 010504 meteorology & atmospheric sciences, Astronomy, media_common.quotation_subject, FOS: Physical sciences, Field of view, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Time domain astronomy, media_common, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Sampling (statistics), Astronomy and Astrophysics, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Sky, Satellite, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Flare
Abstract: The ESA Gaia satellite scans the whole sky with a temporal sampling ranging from seconds and hours to months. Each time a source passes within the Gaia field of view, it moves over 10 CCDs in 45 s and a lightcurve with 4.5 s sampling (the crossing time per CCD) is registered. Given that the 4.5 s sampling represents a virtually unexplored parameter space in optical time domain astronomy, this data set potentially provides a unique opportunity to open up the fast transient sky. We present a method to start mining the wealth of information in the per CCD Gaia data. We perform extensive data filtering to eliminate known on-board and data processing artefacts, and present a statistical method to identify sources that show transient brightness variations on ~2 hours timescales. We illustrate that by using the Gaia photometric CCD measurements, we can detect transient brightness variations down to an amplitude of 0.3 mag on timescales ranging from 15 seconds to several hours. We search an area of ~23.5 square degrees on the sky, and find four strong candidate fast transients. Two candidates are tentatively classified as flares on M-dwarf stars, while one is probably a flare on a giant star and one potentially a flare on a solar type star. These classifications are based on archival data and the timescales involved. We argue that the method presented here can be added to the existing Gaia Science Alerts infrastructure for the near real-time public dissemination of fast transient events., Comment: 10 pages, 5 figures and 5 tables; MNRAS in press
Published: 2018

36. Discovery of New Dipper Stars with K2: A Window into the Inner Disk Region of T Tauri Stars

Author: Christina Hedges, Grant M. Kennedy, and Simon Hodgkin
Subjects: Physics, 010504 meteorology & atmospheric sciences, biology, Dipper, Young stellar object, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, biology.organism_classification, Stellar classification, 01 natural sciences, Stars, T Tauri star, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Ophiuchus, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, 0105 earth and related environmental sciences
Abstract: In recent years a new class of Young Stellar Object has been defined, referred to as dippers, where large transient drops in flux are observed. These dips are too large to be attributed to stellar variability, last from hours to days and can reduce the flux of a star by 10-50\%. This variability has been attributed to occultations by warps or accretion columns near the inner edge of circumstellar disks. Here we present 95 dippers in the Upper Scorpius association and $\rho$ Ophiuchus cloud complex found in K2 Campaign 2 data using supervised machine learning with a Random Forest classifier. We also present 30 YSOs that exhibit brightening events on the order of days, known as bursters. Not all dippers and bursters are known members, but all exhibit infrared excesses and are consistent with belonging to either of the two young star forming regions. We find 21.0 $\pm$ 5.5\% of stars with disks are dippers for both regions combined. Our entire dipper sample consists only of late-type (KM) stars, but we show that biases limit dipper discovery for earlier spectral types. Using the dipper properties as a proxy, we find that the temperature at the inner disk edge is consistent with interferometric results for similar and earlier type stars., Comment: 34 Pages, 21 Figures
Published: 2018
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37. An automated search for transiting exocomets

Author: Simon Hodgkin, Greg Hope, Grant M. Kennedy, Mark C. Wyatt, Kennedy, Grant [0000-0001-6831-7547], Hodgkin, Simon [0000-0002-5470-3962], Wyatt, Mark [0000-0001-9064-5598], and Apollo - University of Cambridge Repository
Subjects: media_common.quotation_subject, Population, Comet, FOS: Physical sciences, Astrophysics, 01 natural sciences, Asymmetry, circumstellar matter, 0103 physical sciences, Transit (astronomy), education, stars: individual: HD182952, infrared: planetary systems, 010303 astronomy & astrophysics, planetary systems, Instrumentation and Methods for Astrophysics (astro-ph.IM), QB, media_common, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, 010308 nuclear & particles physics, comets: general, Astronomy and Astrophysics, Planetary system, Light curve, stars: variables: general, Stars, Space and Planetary Science, Astrophysics - Instrumentation and Methods for Astrophysics, Open cluster, Astrophysics - Earth and Planetary Astrophysics
Abstract: This paper discusses an algorithm for detecting single transits in photometric time-series data. Specifically, we aim to identify asymmetric transits with ingress that is more rapid than egress, as expected for cometary bodies with a significant tail. The algorithm is automated, so can be applied to large samples and only a relatively small number of events need to be manually vetted. We applied this algorithm to all long cadence light curves from the Kepler mission, finding 16 candidate transits with significant asymmetry, 11 of which were found to be artefacts or symmetric transits after manual inspection. Of the 5 remaining events, four are the 0.1% depth events previously identified for KIC 3542116 and 11084727. We identify HD 182952 (KIC 8027456) as a third system showing a potential comet transit. All three stars showing these events have H-R diagram locations consistent with $\sim$100Myr-old open cluster stars, as might be expected given that cometary source regions deplete with age, and giving credence to the comet hypothesis. If these events are part of the same population of events as seen for KIC 8462852, the small increase in detections at 0.1% depth compared to 10% depth suggests that future work should consider whether the distribution is naturally flat, or if comets with symmetric transits in this depth range remain undiscovered. Future searches relying on asymmetry should be more successful if they focus on larger samples and young stars, rather than digging further into the noise., Comment: MNRAS in press
Published: 2018
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38. Low-mass eclipsing binaries in the WFCAM Transit Survey: the persistence of the M-dwarf radius inflation problem

Author: Jayne Birkby, David Barrado, Brigitta Sipocz, Simon Hodgkin, P. Cruz, Marcos P. Diaz, and Low Energy Astrophysics (API, FNWI)
Subjects: FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, ESTRELAS, 01 natural sciences, symbols.namesake, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Markov chain Monte Carlo, Radius, Light curve, Radial velocity, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, symbols, Astrophysics::Earth and Planetary Astrophysics, Low Mass
Abstract: We present the characterization of five new short-period low-mass eclipsing binaries (LMEBs) from the WFCAM Transit Survey. The analysis was performed by using the photometric WFCAM J-mag data and additional low- and intermediate-resolution spectroscopic data to obtain both orbital and physical properties of the studied sample. The light curves and the measured radial velocity curves were modelled simultaneously with the JKTEBOP code, with Markov chain Monte Carlo simulations for the error estimates. The best-model fit have revealed that the investigated detached binaries are in very close orbits, with orbital separations of 2.9 ≤ a ≤ 6.7 R⊙ and short periods of 0.59 ≤ Porb ≤ 1.72 d, approximately. We have derived stellar masses between 0.24 and 0.72 M⊙ and radii ranging from 0.42 to 0.67 R⊙. The great majority of the LMEBs in our sample has an estimated radius far from the predicted values according to evolutionary models. The components with derived masses of M ⊙ present a radius inflation of ∼9 per cent∼9 per cent or more. This general behaviour follows the trend of inflation for partially radiative stars proposed previously. These systems add to the increasing sample of low-mass stellar radii that are not well-reproduced by stellar models. They further highlight the need to understand the magnetic activity and physical state of small stars. Missions like TESS will provide many such systems to perform high-precision radius measurements to tightly constrain low-mass stellar evolution models.
Published: 2018

39. Gaia Data Release 2: Photometric content and validation

Author: P. M. Marrese, A. Delgado, C. Ducourant, P. J. Richards, G. Altavilla, Gerry Gilmore, G. Giuffrida, Łukasz Wyrzykowski, F. De Luise, A. M. Piersimoni, Michael Davidson, M. Riello, C. Diener, Anthony G. A. Brown, D. W. Evans, G. Cocozza, Jordi Portell, S. Marinoni, Marco Castellani, Nicoletta Sanna, A. Kewley, B. Holl, Martin A. Barstow, Michele Bellazzini, N. A. Walton, P. Burgess, P. Osborne, D. Terrett, C. Fabricius, S. Galleti, J. M. Carrasco, Carla Cacciari, Carme Jordi, L. Pulone, Thomas Wevers, D. L. Harrison, Sergey E. Koposov, F. De Angeli, S. Ragaini, G. Busso, Simon Hodgkin, L. Balaguer-Núñez, Paolo Montegriffo, F. van Leeuwen, L. Palaversa, Elena Pancino, CICEnergigune, Nelson Mandela Metropolitan University [Port Elizabeth, South Africa], Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), Department of Biomedical, Metabolic and Neural Sciences [Modena], Centre d'études spatiales de la biosphère (CESBIO), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Bologna (OABO), Istituto Nazionale di Astrofisica (INAF), Universitat de Barcelona (UB), Atotech Deutschland GmbH, Atotech, Hospital Israelita Albert Einstein, M2A 2018, 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)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Heckscher-Klinikum, Department of Astrophysics [Nijmegen], Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud university [Nijmegen]-Radboud university [Nijmegen], Evans, Dafydd [0000-0002-6685-5998], Riello, Marco [0000-0002-3134-0935], Harrison, Diana [0000-0001-8687-6588], Hodgkin, Simon [0000-0002-5470-3962], Gilmore, Gerard [0000-0003-4632-0213], Walton, Nicholas [0000-0003-3983-8778], Apollo - University of Cambridge Repository, and Universitat de Barcelona
Subjects: Astrometria, Astronomy, FOS: Physical sciences, Astrophysics, Surveys, 01 natural sciences, Catàlegs d'estels, catalogs, surveys, instrumentation, photometers, techniques: photometric, galaxies: general, Star catalogs, Photometry (optics), 0103 physical sciences, Instruments astronòmics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Remote sensing, Physics, 010308 nuclear & particles physics, Quality assessment, photometric [Techniques], Astronomical instruments, general [Galaxies], Astronomy and Astrophysics, Astrometry, Galaxies, Galàxies, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], instrumentation: photometers, photometers [Instrumentation], Space and Planetary Science, Content (measure theory), Catalogs, Astrophysics - Instrumentation and Methods for Astrophysics, Data release
Abstract: Aims. We describe the photometric content of the second data release of the Gaia project (Gaia DR2) and its validation along with the quality of the data. Methods. The validation was mainly carried out using an internal analysis of the photometry. External comparisons were also made, but were limited by the precision and systematics that may be present in the external catalogues used. Results. In addition to the photometric quality assessment, we present the best estimates of the three photometric passbands. Various colour-colour transformations are also derived to enable the users to convert between the Gaia and commonly used passbands. Conclusions. The internal analysis of the data shows that the photometric calibrations can reach a precision as low as 2 mmag on individual CCD measurements. Other tests show that systematic effects are present in the data at the 10 mmag level., Comment: This version has corrections to Appendix A. All the SDSS transformations have been corrected. Tables A.1 and A.2 have changed for the SDSS relationships. Three of the subfigures in Figure A.1 have changed. The author list has been expanded
Published: 2018
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40. Gaia 17bpi: An FU Ori Type Outburst

Author: Michael A. Kuhn, Tim Naylor, Roc M. Cutri, Luisa Rebull, Sam Morrell, Lynne A. Hillenbrand, Carlos Contreras Peña, Amy Mainzer, Dirk Froebrich, and Simon Hodgkin
Subjects: 010504 meteorology & atmospheric sciences, Absorption spectroscopy, Infrared, Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Two stages, Young star, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Galactic plane, Light curve, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report on the source Gaia 17bpi and identify it as a new, ongoing FU Ori type outburst, associated with a young stellar object. The optical lightcurve from Gaia exhibited a 3.5 mag rise with the source appearing to plateau in mid/late 2018. Mid-infrared observations from NEOWISE also show a $>$3 mag rise that occurred in two stages, with the second one coincident with the optical brightening, and the first one preceding the optical brightening by $\sim$1.5 years. We model the outburst as having started between October and December of 2014. This wavelength-dependent aspect of young star accretion-driven outbursts has never been documented before. Both the mid-infrared and the optical colors of the object become bluer as the outburst proceeds. Optical spectroscopic characteristics in the outburst phase include: a GK-type absorption spectrum, strong wind/outflow in e.g. Mgb, NaD, H$\alpha$, KI, OI, and CaII profiles, and detection of LiI 6707 \AA. The infrared spectrum in the outburst phase is similar to that of an M-type spectrum, notably exhibiting prominent $H_2O$ and $^{12}$CO (2-0) bandhead absorption in the K-band, and likely HeI wind in the Y-band. The new FU Ori source Gaia 17bpi is associated with a little-studied dark cloud in the galactic plane, located at a distance of 1.27 kpc., Comment: Accepted to ApJ
Published: 2018
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41. A kilonova as the electromagnetic counterpart to a gravitational-wave source

Author: Markus Kromer, Łukasz Wyrzykowski, M. Smith, A. Franckowiak, John L. Tonry, Phil A. James, H. Flewelling, O. McBrien, Thomas Krühler, Andy Lawrence, Christopher W. Stubbs, Ilan Manulis, R. E. Firth, Franz E. Bauer, Giorgos Leloudas, Jesper Sollerman, B. Stalder, T. Schweyer, Nicholas A. Walton, Christopher Waters, Lluís Galbany, Zach Cano, André Müller, S. J. Prentice, Joseph P. Anderson, Ashley J. Ruiter, Nancy Elias-Rosa, Peter G. Jonker, M. E. Huber, Wolfgang Kerzendorf, Helene Szegedi, Eugene A. Magnier, T. M. Reynolds, P. Clark, A. Razza, J. Palmerio, A. S. B. Schultz, Mariusz Gromadzki, C. Frohmaier, Giacomo Terreran, Jochen Greiner, Lorraine Hanlon, Luc Dessart, Stephen J. Smartt, A. Rest, Antonio Martin-Carrillo, Maria Letizia Pumo, Stefan Taubenberger, Arne Rau, Richard J. Wainscoat, Régis Cartier, J. Bulger, Rupak Roy, Ferdinando Patat, Larry Denneau, Giacomo Cannizzaro, Francesco Taddia, D. Homan, Isobel Hook, Darryl Wright, Claudia P. Gutiérrez, A. Nicuesa Guelbenzu, P. Wiseman, Hanindyo Kuncarayakti, J. Vos, K. C. Chambers, Seppo Mattila, Cristina Barbarino, Mark Sullivan, G. Pignata, Luke J. Shingles, Morgan Fraser, Kate Maguire, A. Hamanowicz, F. Onori, M.-S. Hernandez, Marco Berton, Mark Willman, Ting-Wan Chen, A. Heinze, Jussi Harmanen, A. De Cia, Mattia Bulla, Luca Izzo, David Young, M. Della Valle, Aleksandar Cikota, Michael W. Coughlin, K. W. Smith, Marek Kowalski, T. Lowe, C. Agliozzo, Patricia Schady, Anders Jerkstrand, Georgios Dimitriadis, Lána Salmon, M. R. Magee, Erkki Kankare, A. Flörs, C. Angus, O. Yaron, H. Weiland, Avishay Gal-Yam, M. T. Botticella, Ph. Podsiadlowski, Simon Hodgkin, Cosimo Inserra, Santiago González-Gaitán, S. Klose, Krzysztof A. Rybicki, Chris Ashall, Ivo R. Seitenzahl, Andrea Pastorello, Z. Kostrzewa-Rutkowska, Stuart A. Sim, Rubina Kotak, M. Dennefeld, Kasper E. Heintz, Jakob Nordin, J. D. Lyman, B. van Soelen, D. O'Neill, Oskar Klein Centre [Stockholm], Stockholm University, Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Aberystwyth University, Federal Institute for Geosciences and Natural Resources (BGR), Dark Cosmology Centre (DARK), Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Department of Particle Physics and Astrophysics, Weizmann Institute of Science [Rehovot, Israël], Laboratoire de recherche en Hydrodynamique, Énergétique et Environnement Atmosphérique (LHEEA), École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS), Physik-Institut, Universität Zürich [Zürich] (UZH), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), SLAC National Accelerator Laboratory (SLAC), Stanford University, Department of Physics [Pittsburgh], Carnegie Mellon University [Pittsburgh] (CMU), Max-Planck-Institut für Extraterrestrische Physik (MPE), Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), University of Oxford Astrophysics, Università degli Studi di Roma 'La Sapienza' [Rome], Institut de biologie et chimie des protéines [Lyon] (IBCP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Department of Astrophysics [Nijmegen], Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud university [Nijmegen]-Radboud university [Nijmegen], Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), The Oskar Klein Centre for Cosmoparticle Physics and Department of Physics, Stockholm University, Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), AUTRES, CIC Tours, Centre Hospitalier Régional Universitaire de Tours (CHRU Tours)-Hôpital Bretonneau-Université de Tours-Institut National de la Santé et de la Recherche Médicale (INSERM), Simulation et Traitement de l'information pour l'Exploitation des systèmes de Production (EDF R&D STEP), EDF R&D (EDF R&D), EDF (EDF)-EDF (EDF), Commissariat à l'Energie Atomique, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche Contre les Cancers de l'Appareil Digestif-European Institute of Telesurgery (IRCAD/EITS), Université Louis Pasteur - Strasbourg I, Crop and Weed Ecology, Plant Sciences Group, Wageningen University and Research [Wageningen] (WUR), Astronomical Observatory [Warsaw], Faculty of Physics [Warsaw] (FUW), University of Warsaw (UW)-University of Warsaw (UW), Institut d'Astrophysique de Paris ( IAP ), and Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: neutron star: binary, Astronomy, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics, Kilonova, 01 natural sciences, ddc:070, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, nuclide, QC, ComputingMilieux_MISCELLANEOUS, QB, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, [PHYS]Physics [physics], Solar mass, Multidisciplinary, neutron star: mass, radioactivity, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, r-process, Astrophysics::Earth and Planetary Astrophysics, ST/P000495/1, Astrophysics - High Energy Astrophysical Phenomena, velocity, radiation: electromagnetic, Opacity, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, gamma ray: burst, gravitational radiation: direct detection, Electromagnetic radiation, 0103 physical sciences, General, STFC, Astrophysics::Galaxy Astrophysics, ta115, 010308 nuclear & particles physics, Gravitational wave, gravitational radiation, RCUK, opacity, ST/M005348/1, Galaxy, black hole: binary, 13. Climate action, gravitational radiation: emission, ST/P000312/1, galaxy, Gamma-ray burst, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Gravitational waves were discovered with the detection of binary black hole mergers and they should also be detectable from lower mass neutron star mergers. These are predicted to eject material rich in heavy radioactive isotopes that can power an electromagnetic signal called a kilonova. The gravitational wave source GW170817 arose from a binary neutron star merger in the nearby Universe with a relatively well confined sky position and distance estimate. Here we report observations and physical modelling of a rapidly fading electromagnetic transient in the galaxy NGC4993, which is spatially coincident with GW170817 and a weak short gamma-ray burst. The transient has physical parameters broadly matching the theoretical predictions of blue kilonovae from neutron star mergers. The emitted electromagnetic radiation can be explained with an ejected mass of 0.04 +/- 0.01 Msol, with an opacity of kappa, Nature, in press, DOI 10.1038/nature24303. Data files will be made available at http://www.pessto.org
Published: 2017
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42. First evidence of multiple populations along the AGB from Str\'omgren photometry

Author: Aldo Serenelli, P. Gruyters, Antonino Milone, Sofia Feltzing, Luca Casagrande, and Simon Hodgkin
Subjects: Physics, Stellar population, 010308 nuclear & particles physics, Techniques: Photometric, Stars: Abundances, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Photometry (optics), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Globular cluster, 0103 physical sciences, Cluster (physics), Hertzsprung-Russell and C-M diagrams, Globular clusters: General, 010303 astronomy & astrophysics, Evolutionary theory
Abstract: Spectroscopic studies have demonstrated that nearly all Galactic globular clusters (GCs) harbour multiple stellar populations with different chemical compositions. Moreover, colour-magnitude diagrams based exclusively on Str\"omgrem photometry have allowed us to identify and characterise multiple populations along the RGB of a large number of clusters. In this paper we show for the first time that Str\"omgren photometry is also very effcient at identifying multiple populations along the AGB, and demonstrate that the AGB of M3, M92, NGC362, NGC1851, and NGC6752 are not consistent with a single stellar population. We also provide a catalogue of RGB and AGB stars photometrically identified in these clusters for further spectroscopic follow-up studies.We combined photometry and elemental abundances from the literature for RGB and AGB stars in NGC6752 where the presence of multiple populations along the AGB has been widely debated. We find that, while the MS, SGB, and RGB host three stellar populations with different helium and light element abundances, only two populations of AGB stars are present in the cluster. These results are consistent with standard evolutionary theory., Comment: 9 pages, 3 figures, 1 table in the main article, 3 tables in the appendix of which 2 tables containing coordinates and photometry of photometrically identified RGB and AGB stars
Published: 2017

43. Ground based follow-up for Gaia Science Alerts: First results

Author: Guy Rixon, E. de Miguel, Gerry Gilmore, Simon Hodgkin, Łukasz Wyrzykowski, P. Wielgórski, Sergey E. Koposov, S. van Velzen, Heather Campbell, Manuel A. P. Torres, Morgan Fraser, Krzysztof A. Rybicki, F. van Leeuwen, Nadejda Blagorodnova, Gisella Clementini, N. A. Walton, Peter G. Jonker, G. Altavilla, and Thomas Wevers
Subjects: Physics, Space and Planetary Science, General Engineering, Astronomy and Astrophysics, Transient (computer programming), Data science
Abstract: The Gaia Science Alerts project (GSA) aims to augment a precision survey of the Milky Way with a controlled, precision survey of all classes of transient phenomena. While onboard BP/RP spectra from Gaia will ultimately allow us to classify many Gaia Alerts based on Gaia data alone, in the initial phases of the GSA project it is necessary to verify and classify discoveries with ground-based spectroscopic followup. In this article, we describe a subset of the ongoing Gaia Alerts followup programmes, and some of the initial science results from this work.
Published: 2014
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44. J-band variability of M dwarfs in the WFCAM Transit Survey

Author: Simon Hodgkin, C. del Burgo, Eric Martin, N. Goulding, Hugh R. A. Jones, M. C. Gálvez-Ortiz, Silvia Catalan, S. V. Nefs, B. Sipőcz, Jayne Birkby, Géza Kovács, John R. Barnes, S. V. Jeffers, and D. J. Pinfield
Subjects: Physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, J band, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Transit (astronomy), Low Mass, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract: We present an analysis of the photometric variability of M dwarfs in the WFCAM Transit Survey. Although periodic lightcurve variability in low mass stars is generally dominated by photospheric star spot activity, M dwarf variability in the J band has not been as thoroughly investigated as at visible wavelengths. Spectral type estimates for a sample of over 200,000 objects are made using spectral type-colour relations, and over 9600 dwarfs (J0.2 mag flaring event from an M4V star in our sample., 18 pages, 18 figures, 2 tables, accepted in MNRAS
Published: 2012
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45. Time-resolved spectroscopy of the variable brown dwarf Kelu-1

Author: C. G. Tinney, Fraser Clarke, and Simon Hodgkin
Subjects: Medium resolution, Physics, Photometry (optics), Rotation period, Space and Planetary Science, Astrophysics (astro-ph), Brown dwarf, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Time-resolved spectroscopy, Spectral line
Abstract: We report the results of observations designed to investigate the spectroscopic signatures of dust clouds on the L2 brown dwarf Kelu-1. Time resolved medium resolution spectra show no significant evidence of variability in the dust sensitive TiO, CrH and FeH bandheads on the timescale of 1--24 hours. We do however report periodic variability in the psuedo-equivelent width of H-alpha consistent with the 1.8 hour rotation period previously reported for this object Clarke, Tinney & Tolley (2002). Near-contemporaneous I-band photometry shows evidence for non-periodic variability at the level of 2%., 9 pages, 12 figures. MNRAS in press
Published: 2016

46. V5852 Sgr: An Unusual Nova Possibly Associated with the Sagittarius Stream

Author: M. Yamagishi, Robert Williams, A. Iwamatsu, P. Mróz, Takahiro Nagayama, Alexis M. S. Smith, Shazrene Mohamed, Tsuguru Ryu, Alexander Scholz, Łukasz Wyrzykowski, Patricia A. Whitelock, E. Aydi, I. Kawamata, Petri Väisänen, Martin Dominik, Andrzej Udalski, Hiroki Onozato, Shogo Nishiyama, Simon Hodgkin, and University of St Andrews. School of Physics and Astronomy
Subjects: Extrasolare Planeten und Atmosphären, Astrophysics::High Energy Astrophysical Phenomena, NDAS, FOS: Physical sciences, Astrophysics, Sagittarius Stream, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Photometry (optics), Bulge, 0103 physical sciences, Novae, cataclysmic variables, QB Astronomy, cataclysmic variables – white dwarfs, Astrophysics::Solar and Stellar Astrophysics, Disc, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QC, Astrophysics::Galaxy Astrophysics, QB, Physics, 010308 nuclear & particles physics, White dwarf, Astronomy, White dwarfs, Astronomy and Astrophysics, Light curve, Dwarf spheroidal galaxy, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, binaries: close – novae, Astrophysics::Earth and Planetary Astrophysics, Sagittarius, close [Binaries]
Abstract: We report spectroscopic and photometric follow-up of the peculiar nova V5852~Sgr (discovered as OGLE-2015-NOVA-01), which exhibits a combination of features from different nova classes. The photometry shows a flat-topped light curve with quasi-periodic oscillations, then a smooth decline followed by two fainter recoveries in brightness. Spectroscopy with the Southern African Large Telescope shows first a classical nova with an Fe II or Fe IIb spectral type. In the later spectrum, broad emissions from helium, nitrogen and oxygen are prominent and the iron has faded which could be an indication to the start of the nebular phase. The line widths suggest ejection velocities around $1000\,{\rm km\,s^{-1}}$. The nova is in the direction of the Galactic bulge and is heavily reddened by an uncertain amount. The $V$ magnitude 16 days after maximum enables a distance to be estimated and this suggests that the nova may be in the extreme trailing stream of the Sagittarius dwarf spheroidal galaxy. If so it is the first nova to be detected from that, or from any dwarf spheroidal galaxy. Given the uncertainty of the method and the unusual light curve we cannot rule out the possibility that it is in the bulge or even the Galactic disk behind the bulge., Accepted for publication in MNRAS on June 8th, 2016 (11 pages, 8 figures, 5 tables)
Published: 2016

47. The Chandra Galactic Bulge Survey: optical catalogue and point-source counterparts to X-ray sources

Author: Gijs Nelemans, Danny Steeghs, Peter G. Jonker, Robert I. Hynes, Thomas J. Maccarone, C. T. Britt, T. van Grunsven, Thomas Wevers, E. A. Gonzalez-Solares, Manuel A. P. Torres, Jianfeng Wu, Christopher J. Johnson, Simon Hodgkin, Craig O. Heinke, and C. G. Bassa
Subjects: Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Line-of-sight, 010308 nuclear & particles physics, Point source, Astronomy, X-ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, All optical, Photometry (astronomy), Space and Planetary Science, Bulge, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries)
Abstract: As part of the Chandra Galactic Bulge Survey (GBS), we present a catalogue of optical sources in the GBS footprint. This consists of two regions centered at Galactic latitude b = 1.5 degrees above and below the Galactic Centre, spanning (l x b) = (6x1) degrees. The catalogue consists of 2 or more epochs of observations for each line of sight in r', i' and H{\alpha} filters. It is complete down to r' = 20.2 and i' = 19.2 mag; the mean 5{\sigma} depth is r' = 22.5 and i' = 21.1 mag. The mean root-mean-square residuals of the astrometric solutions is 0.04 arcsec. We cross-correlate this optical catalogue with the 1640 unique X-ray sources detected in Chandra observations of the GBS area, and find candidate optical counterparts to 1480 X-ray sources. We use a false alarm probability analysis to estimate the contamination by interlopers, and expect ~ 10 per cent of optical counterparts to be chance alignments. To determine the most likely counterpart for each X-ray source, we compute the likelihood ratio for all optical sources within the 4{\sigma} X-ray error circle. This analysis yields 1480 potential counterparts (~ 90 per cent of the sample). 584 counterparts have saturated photometry (r', Comment: 18 pages, 18 figures. Published in MNRAS. 2016MNRAS.458.4530W
Published: 2016

48. The first planet detected in the WTS: an inflated hot Jupiter in a 3.35 d orbit around a late F star

Author: Eric Martin, Don Pollacco, Amelia Bayo, Luca Fossati, D. Mislis, N. Lodieu, R. Tata, J. Zendejas, Federico Marocco, Bas Nefs, David A. Campbell, R. P. Saglia, C. del Burgo, H. R. A. Jones, D. J. Pinfield, P. Cruz, G. Kovács, Ralf Napiwotzki, John R. Barnes, M. Kuznetsov, L. Sarro Baro, M. C. Gálvez-Ortiz, Enrique Solano, Felipe Murgas, Ignas Snellen, Simon Hodgkin, David Barrado, Enric Palle, H. Stoev, B. Sipőcz, Carole A. Haswell, O. Ivanyuk, Johannes Koppenhoefer, Jayne Birkby, P. R. Steele, M. Cappetta, Silvia Catalan, Y. Pavlenko, and N. Goulding
Subjects: Physics, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Planetary system, Light curve, Orbital period, Exoplanet, Radial velocity, Space and Planetary Science, Planet, Hot Jupiter, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Planetary mass, Astrophysics::Galaxy Astrophysics
Abstract: We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope. Light curves comprising almost 1200 epochs with a photometric precision of better than 1 per cent to J � 16 were constructed for � 60000 stars and searched for periodic transit signals. For one of the most promising transiting candidates, highresolution spectra taken at the Hobby-Eberly Telescope allowed us to estimate the spectroscopic parameters of the host star, a late-F main sequence dwarf (V=16.13) with possibly slightly subsolar metallicity, and to measure its radial velocity variations. The combined analysis of the light curves and spectroscopic data resulted in an orbital period of the substellar companion of 3.35 days, a planetary mass of 4.01±0.35MJ, and a planetary radius of 1.49 +0.16 0.18 RJ. WTS-1b has one of the largest radius anomalies among the known hot Jupiters in the mass range 3-5MJ.
Published: 2012
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49. A photometric and astrometric investigation of the brown dwarfs in Blanco 1

Author: Sarah L. Casewell, Estelle Moraux, D. E. A. Baker, Simon Hodgkin, Richard F. Jameson, and Paul Dobbie
Subjects: Physics, education.field_of_study, Population, Infrared telescope, Brown dwarf, Northern Hemisphere, Astronomy and Astrophysics, Astrophysics, law.invention, Telescope, Space and Planetary Science, law, Pleiades, education, Low Mass, Open cluster
Abstract: We present the results of a photometric and astrometric study of the low mass stellar and substellar population of the young open cluster Blanco 1. We have exploited J band data, obtained recently with the Wide Field Camera (WFCAM) on the United Kingdom InfraRed Telescope (UKIRT), and 10 year old I and z band optical imaging from CFH12k and Canada France Hawaii Telescope (CFHT), to identify 44 candidate low mass stellar and substellar members, in an area of 2 sq. degrees, on the basis of their colours and proper motions. This sample includes five sources which are newly discovered. We also confirm the lowest mass candidate member of Blanco 1 unearthed so far (29MJup). We determine the cluster mass function to have a slope of alpha=+0.93, assuming it to have a power law form. This is high, but nearly consistent with previous studies of the cluster (to within the errors), and also that of its much better studied northern hemisphere analogue, the Pleiades.
Published: 2012
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50. Four ultra-short-period eclipsing M-dwarf binaries in the WFCAM Transit Survey

Author: M. Cappetta, Yakiv V. Pavlenko, J. Zendejas, E. L. Martin, J. Koppenhofer, C. del Burgo, S. V. Nefs, D. J. Pinfield, David Barrado, P. Cruz, N. Goulding, Jayne Birkby, D. Mislis, Géza Kovács, Ignas Snellen, H. Stoev, Simon Hodgkin, Brigitta Sipocz, and Roberto P. Saglia
Subjects: Physics, Orbit, Angular momentum, Stars, Period (periodic table), Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Binary system, Astrophysics, Transit (astronomy)
Abstract: We report on the discovery of four ultra-short period (P
Published: 2012
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