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8 results on '"Wittkowski, Markus"'

1. The effect of winds in red supergiants: modeling for interferometry

Author

González-Torà, Gemma, Wittkowski, Markus, Davies, Ben, and Plez, Bertrand

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

Red supergiants (RSGs) are evolved massive stars in a stage preceding core-collapse supernova. Understanding evolved-phases of these cool stars is key to understanding the cosmic matter cycle of our Universe, since they enrich the cosmos with newly formed elements. However, the physical processes that trigger mass loss in their atmospheres are still not fully understood, and remain one of the key questions in stellar astrophysics. We use a new method to study the extended atmospheres of these cold stars, exploring the effect of a stellar wind for both a simple radiative equilibrium model and a semi-empirical model that accounts for a chromospheric temperature structure. We then can compute the intensities, fluxes and visibilities matching the observations for the different instruments at the Very Large Telescope Interferometer (VLTI). Specifically, when comparing with the atmospheric structure of HD 95687 based on published VLTI/AMBER data, we find that our model can accurately match these observations in the Kband, showing the enormous potential of this methodology to reproduce extended atmospheres of RSGs., 6 pages, 5 figures, to appear at the Proceedings of the IAUS370: Winds of stars and exoplanets. Eds: A. Vidotto and M. Smith-Spanier. Based on a contributed talk on preliminary work from Gonz\'alez-Tor\`a et al., submitted to A&A

Published
2022

2. Multiple star systems in the Orion nebula

Author

GRAVITY Collaboration, Karl, Martina, Pfuhl, Oliver, Eisenhauer, Frank, Genzel, Reinhard, Grellmann, Rebekka, Habibi, Maryam, Abuter, Roberto, Accardo, Matteo, Amorim, Ant��nio, Anugu, Narsireddy, ��vila, Gerardo, Benisty, Myriam, Berger, Jean-Philippe, Bland, Nicolas, Bonnet, Henri, Bourget, Pierre, Brandner, Wolfgang, Brast, Roland, Buron, Alexander, Garatti, Alessio Caratti o, Chapron, Fr��d��ric, Cl��net, Yann, Collin, Claude, Foresto, Vincent Coud�� du, de Wit, Willem-Jan, de Zeeuw, Tim, Deen, Casey, Delplancke-Str��bele, Fran��oise, Dembet, Roderick, Derie, Fr��d��ric, Dexter, Jason, Duvert, Gilles, Ebert, Monica, Eckart, Andreas, Esselborn, Michael, F��dou, Pierre, Finger, Gert, Garcia, Paulo, Dabo, Cesar Enrique Garcia, Lopez, Rebeca Garcia, Gao, Feng, Gandron, ��ric, Gillessen, Stefan, Gont��, Fr��d��ric, Gordo, Paulo, Gr��zinger, Ulrich, Guajardo, Patricia, Guieu, Sylvain, Haguenauer, Pierre, Hans, Oliver, Haubois, Xavier, Haug, Marcus, Hau��mann, Frank, Henning, Thomas, Hippler, Stefan, Horrobin, Matthew, Huber, Armin, Hubert, Zoltan, Hubin, Norbert, Hummel, Christian A., Jakob, Gerd, Jochum, Lieselotte, Jocou, Laurent, Kaufer, Andreas, Kellner, Stefan, Kandrew, Sarah, Kern, Lothar, Kervella, Pierre, Kiekebusch, Mario, Klein, Ralf, K��hler, Rainer, Kolb, Johan, Kulas, Martin, Lacour, Sylvestre, Lapeyr��re, Vincent, Lazareff, Bernard, Bouquin, Jean-Baptiste Le, L��na, Pierre, Lenzen, Rainer, L��v��que, Samuel, Lin, Chien-Cheng, Lippa, Magdalena, Magnard, Yves, Mehrgan, Leander, M��rand, Antoine, Moulin, Thibaut, M��ller, Eric, M��ller, Friedrich, Neumann, Udo, Oberti, Sylvain, Ott, Thomas, Pallanca, Laurent, Panduro, Johana, Pasquini, Luca, Paumard, Thibaut, Percheron, Isabelle, Perraut, Karine, Perrin, Guy, Pfl��ger, Andreas, Duc, Thanh Phan, Plewa, Philipp M., Popovic, Dan, Rabien, Sebastian, Ram��rez, Andr��s, Ramos, Jose, Rau, Christian, Riquelme, Miguel, Rodr��guez-Coira, Gustavo, Rohloff, Ralf-Rainer, Rosales, Alejandra, Rousset, G��rard, Sanchez-Bermudez, Joel, Scheithauer, Silvia, Sch��ller, Markus, Schuhler, Nicolas, Spyromilio, Jason, Straub, Odele, Straubmeier, Christian, Sturm, Eckhard, Suarez, Marcos, Tristram, Konrad R. W., Ventura, Noel, Vincent, Fr��d��ric, Waisberg, Idel, Wank, Imke, Widmann, Felix, Wieprecht, Ekkehard, Wiest, Michael, Wiezorrek, Erich, Wittkowski, Markus, Woillez, Julien, Wolff, Burkhard, Yazici, Senol, Ziegler, Denis, Zins, G��rard, Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, European Southern Observatory (ESO), SIM/IDL Faculdade de Ciências da Universidade de Lisboa (FCUL), University of Lisboa, CENTRA Instituto Superior Tecnico, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory [Santiago] (ESO), Max-Planck-Institut für Astronomie (MPIA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astronomie et techniques spatiales, Université Paris Diderot - Paris 7 (UPD7), Physikalisches Institut [Köln], Universität zu Köln, Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto [Porto], State Key Laboratory of Molecular Developmental Biology, Institute of genetics and developmental Biology, CAS, CENTRA, Universidade de Lisboa, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), leiden Obsevatory, Universiteit Leiden [Leiden], Laboratoire d'Astrophysique, Laboratoire des interactions plantes micro-organismes (LIPM), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Matériaux divisés, interfaces, réactivité, électrochimie (MADIREL), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Michigan State University [East Lansing], Michigan State University System, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universität zu Köln = University of Cologne, Universidade do Porto = University of Porto, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universiteit Leiden, Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), European Project: 8003119(1980), Universidade do Porto, and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Initial mass function, Population, FOS: Physical sciences, Star count, Astrophysics, 01 natural sciences, 0103 physical sciences, Orion Nebula, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, O-type star, Physics, [PHYS]Physics [physics], education.field_of_study, 010308 nuclear & particles physics, Astronomy and Astrophysics, Mass ratio, Accretion (astrophysics), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

This work presents an interferometric study of the massive-binary fraction in the Orion Trapezium Cluster with the recently comissioned GRAVITY instrument. We observe a total of 16 stars of mainly OB spectral type. We find three previously unknown companions for $\theta ^1$ Ori B, $\theta ^2$ Ori B, and $\theta ^2$ Ori C. We determine a separation for the previously suspected companion of NU Ori. We confirm four companions for $\theta ^1$ Ori A, $\theta ^1$ Ori C, $\theta ^1$ Ori D, and $\theta ^2$ Ori A, all with substantially improved astrometry and photometric mass estimates. We refine the orbit of the eccentric high-mass binary $\theta ^1$ Ori C and we are able to derive a new orbit for $\theta ^1$ Ori D. We find a system mass of 21.7 $M_{\odot}$ and a period of $53$ days. Together with other previously detected companions seen in spectroscopy or direct imaging, eleven of the 16 high-mass stars are multiple systems. We obtain a total number of 22 companions with separations up to 600 AU. The companion fraction of the early B and O stars in our sample is about 2, significantly higher than in earlier studies of mostly OB associations. The separation distribution hints towards a bimodality. Such a bimodality has been previously found in A stars, but rarely in OB binaries, which up to this point have been assumed to be mostly compact with a tail of wider companions. We also do not find a substantial population of equal-mass binaries. The observed distribution of mass ratios declines steeply with mass, and like the direct star counts, indicates that our companions follow a standard power law initial mass function. Again, this is in contrast to earlier findings of flat mass ratio distributions in OB associations. We exclude collision as a dominant formation mechanism but find no clear preference for core accretion or competitive accretion., Comment: Accepted for publication in A&A

Published
2018
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3. Science cases for a visible interferometer

Author

Stee, Philippe, Allard, France, Benisty, Myriam, Bigot, Lionel, Blind, Nicolas, Boffin, Henri, Fernandes, Marcelo Borges, Carciofi, Alex, Chiavassa, Andrea, Creevey, Orlagh, Cruzalebes, Pierre, de Wit, Willem-Jan, de Souza, Armando Domiciano, Elvis, Martin, Fabas, Nicolas, Faes, Daniel, Gallenne, Alexandre, Pena, Carlos Guerrero, Hillen, Michel, Hoenig, Sebastian, Ireland, Michael, Kervella, Pierre, Kishimoto, Makoto, Kostogryz, Nadia, Kraus, Stefan, Labeyrie, Antoine, Bouquin, Jean-Baptiste Le, Lebre, Agn��s, Ligi, Roxanne, Marconi, Alessandro, Marsh, Thomas, Meilland, Anthony, Millour, Florentin, Monnier, John, Mourard, Denis, Nardetto, Nicolas, Ohnaka, Keiichi, Paladini, Claudia, Perraut, Karine, Perrin, Guy, Petit, Pascal, Petrov, Romain, Rakshit, Suvendu, Schaefer, Gail, Schneider, Jean, Shulyak, Denis, Simon, Michal, Soulez, Ferreol, Steeghs, Danny, Tallon-Bosc, Isabelle, Tallon, Michel, Brummelaar, Theo ten, Thiebaut, Eric, Th��venin, Fr��d��ric, Van Winckel, Hans, Wittkowski, Markus, and Zorec, Juan

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics - Astrophysics of Galaxies, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

High spatial resolution is the key for the understanding various astrophysical phenomena. But even with the future E-ELT, single dish instruments are limited to a spatial resolution of about 4 mas in the visible. For the closest objects within our Galaxy most of the stellar photosphere remains smaller than 1 mas. With the success of long baseline interferometry these limitations were soom overcome. Today low and high resolution interferometric instruments on the VLTI and CHARA offer an immense range of astrophysical studies. Combining more telescopes and moving to visible wavelengths broadens the science cases even more. With the idea of developing strong science cases for a future visible interferometer, we organized a science group around the following topics: pre-main sequence and main sequence stars, fundamental parameters, asteroseismology and classical pulsating stars, evolved stars, massive stars, active galactic nuclei (AGNs) and imaging techniques. A meeting was organized on the 15th and 16th of January, 2015 in Nice with the support of the Action Specific in Haute Resolution Angulaire (ASHRA), the Programme National en Physique Stellaire (PNPS), the Lagrange Laboratory and the Observatoire de la Cote d'Azur, in order to present these cases and to discuss them further for future visible interferometers. This White Paper presents the outcome of the exchanges. This book is dedicated to the memory of our colleague Olivier Chesneau who passed away at the age of 41., White Paper prospective. This book is dedicated to the memory of our colleague Olivier Chesneau who passed away at the age of 41. v2 includes some corrections to text

Published
2017

4. First light for GRAVITY: Phase referencing optical interferometry for the Very Large Telescope Interferometer

Author

Abuter, Roberto, Accardo, Matteo, Antonio, Amorim, Narsireddy, Anugu, Avila, Gerardo, Azouaoui, N., Benisty, Myriam, Berger, Jean-Philippe, Blind, Nicolas, Bonnet, Henri, Bourget, Pierre, Brandner, Wolfgang, Brast, Roland, Buron, Alexander, Burtscher, L., Cassaing, Frederic, Chapron, Frédéric, Choquet, Elodie, Clénet, Yann, Collin, Claude, Coudé du Forestol, Vincent, de Wit, Willem-Jan, De Zeeuw, Tim, Casey, Deen, Delplancke-Ströbele, Françoise, Dembet, Roderick, Derie, Frédéric, Dexter, Jason, Duvert, Gilles, Ebert, Monica, Eckart, Andreas, Eisenhauer, Frank, Michael, Esselborn, Fédou, Pierre, Finger, Gert, Garcia, Paulo, Garcia Dabo, Cesar Enrique, Garcia Lopez, Rebeca, Gendron, Eric, Genzel, Reinhard, Gillessen, Stefan, Conté, Frédéric, Gordo, Paulo, Grould, Marion, Groözinger, Ulrich, Guieu, Sylvain, Haguenauer, Pierre, Hans, Olivier, Haubois, Xavier, Haug, Marcus, Haussmann, Frank, Henning, Thomas, Hippler, Stefan, Horrobin, Matthew, Huber, Armin, Hubert, Zoltan, Hubin, Norbert, Hummel, Christian, Jakob, Gerd, Janssen, A., Jochum, Lieselotte, Jocou, Laurent, Kaufer, Andreas, Kellner, Stefan, Kendrew, Sarah, Kern, Lothar, Kervella, Pierre, Kiekebusch, Mario, Klein, Ralf, Kok, Y., Kolb, Johan, Kulas, Martin, Lacour, Sylvestre, Lapeyrère, Vincent, Lazareff, Bernard, Le Bouquin, Jean-Baptiste, Léna, Pierre, Lenzen, Rainer, Levêque, Samuel, Lippa, Magdalena, Magnard, Yves, Mehrgan, Leander, Mellein, Marcus, Merand, Antoine, Moreno-Ventas, Javier, Moulin, Thibaut, Müller, Eric, Müller, Fredrich, Neumann, Udo, Oberti, Sylvain, Ott, Thomas, Pallanca, Laurent, Panduro, Johana, Pasquini, Luca, Paumard, Thibaut, Percheron, Isabelle, Perraut, Karine, Perrin, Guy, Pflüger, Andreas, Pfuhl, Olivier, Duc, Thanh Phan, Plewa, Philipp, Popovic, Dan, Rabien, Sebastian, Ramirez, Andres, Ramos, Jose, Rau, Christian, Riquelme, Miguel, Rohloff, Ralf-Rainer, Rousset, Gérard, Sanchez-Bermudez, Joel, Scheithauer, Sylvia, Schöller, Marcus, Schuhler, Nicolas, Spyromilio, Jason, Straubmeier, Christian, Sturm, Eckhard, Suarez, Marco, Tristram, Konrad, Ventura, Noel, Vincent, Frédéric, Waisberg, Idel, Wank, Imke, Weber, J., Wieprecht, Ekkehard, Wiest, Michael, Wiezorrek, Erich, Wittkowski, Markus, Woillez, Julien, Wolff, Burkhard, Yazici, Senol, Ziegler, Denis, Zins, Gérard, Amorim, A., Anugu, N., Ávila, G., Clenet, Y., Coudé Du Foresto, V., de Zeeuw, P., Deen, C., Esselborn, M., Dabo, C, Gonte, F., Grözinger, U., Henning, Th, Le Bouquin, J.-B, Lèna, P., Lévêque, S., Mérand, A., Muller, E., Muller, F., Phan Duc, T., Ramírez, A., Garcia Dabo, E., Henning, Th., Le Bouquin, B., Plewa, M., European Southern Observatory (ESO), CENTRA, Universidade de Lisboa, CENTRA, Universidade do Porto, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Max Planck Institute for Extraterrestrial Physics (MPE), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], ONERA - The French Aerospace Lab [Châtillon], ONERA, Physikalisches Institut [Köln], Universität zu Köln, Max Planck Institute for Radio Astronomy, Department of Physics [Berkeley], University of California [Berkeley], University of California-University of California, European Space Agency (ESA), European Southern Observatory [Santiago] (ESO), Institute Patology and Imunology Molecular, Fac Ciencias, Universidade do Porto [Porto], Brain Mind Institute (BMI - EPFL), Ecole Polytechnique Fédérale de Lausanne (EPFL), Technische Universität Dresden (TUD), Departamento de Control Automático (CINVESTAV-IPN), Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV-IPN), Universidade do Porto, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), ONERA-Université Paris Saclay (COmUE), GRAVITY Collaboration, European Southern Observatory ( ESO ), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Planétologie et d'Astrophysique de Grenoble ( IPAG ), Observatoire des Sciences de l'Univers de Grenoble ( OSUG ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire Astronomique de l'Université de Genève ( ObsGE ), Université de Genève ( UNIGE ), Max-Planck-Institut für Astronomie ( MPIA ), Max Planck Institute for Extraterrestrial Physics ( MPE ), ONERA - The French Aerospace Lab ( Chatillon ), Max Planck Institute for Radio Astronomy, Bonn, European Space Agency ( ESA ), Universidad de Santiago de Chile [Santiago] ( USACH ), European Southern Observatory [Santiago] ( ESO ), University of Porto, Center for Brain Simulation, Ecole Polytechnique Fédérale de Lausanne, Technische Universität Dresden ( TUD ), Departamento de Control Automático ( CINVESTAV-IPN ), Center for Research and Advanced Studies of the National Polytechnic Institute ( CINVESTAV-IPN ), Universidade do Porto = University of Porto, Université de Genève = University of Geneva (UNIGE), Universiteit Leiden, Universität zu Köln = University of Cologne, University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), and Agence Spatiale Européenne = European Space Agency (ESA)

Subjects
[ SPI.SIGNAL ] Engineering Sciences [physics]/Signal and Image processing, Astrophysics, ÉTOILE DOUBLE, OPTIQUE ADAPTATIVE, 01 natural sciences, law.invention, law, Astrophysics::Solar and Stellar Astrophysics, INSTRUMENTATION OPTIQUE, INSTRUMENTATION, instrumentation: interferometers, 010303 astronomy & astrophysics, Physics, Galaxy: center, Galactic Center, Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], [ PHYS.PHYS.PHYS-SPACE-PH ] Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], quasars: emission lines, Interferometry, EMISSION LINE, Closure phase, binaries: symbiotic, Astrophysics::Earth and Planetary Astrophysics, [ SPI.OPTI ] Engineering Sciences [physics]/Optics / Photonic, Astrophysics - Instrumentation and Methods for Astrophysics, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, CENTER, INTERFEROMETRIE GRANDE BASE, FOS: Physical sciences, stars: pre-main sequence, instrumentation: adaptive optics, QUASAR, 010309 optics, Telescope, 0103 physical sciences, Angular resolution, INTERFEROMETERS, Instrumentation and Methods for Astrophysics (astro-ph.IM), CENTRE GALACTIQUE, Astrophysics::Galaxy Astrophysics, ADAPTIVE OPTICS, Very Large Telescope, Astronomy and Astrophysics, First light, GALAXY, Space and Planetary Science, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

GRAVITY is a new instrument to coherently combine the light of the European Southern Observatory Very Large Telescope Interferometer to form a telescope with an equivalent 130 m diameter angular resolution and a collecting area of 200 m$^2$. The instrument comprises fiber fed integrated optics beam combination, high resolution spectroscopy, built-in beam analysis and control, near-infrared wavefront sensing, phase-tracking, dual beam operation and laser metrology [...]. This article gives an overview of GRAVITY and reports on the performance and the first astronomical observations during commissioning in 2015/16. We demonstrate phase tracking on stars as faint as m$_K$ ~ 10 mag, phase-referenced interferometry of objects fainter than m$_K$ ~ 15 mag with a limiting magnitude of m$_K$ ~ 17 mag, minute long coherent integrations, a visibility accuracy of better than 0.25 %, and spectro-differential phase and closure phase accuracy better than 0.5{\deg}, corresponding to a differential astrometric precision of better than 10 microarcseconds ({\mu}as). The dual-beam astrometry, measuring the phase difference of two objects with laser metrology, is still under commissioning. First observations show residuals as low as 50 {\mu}as when following objects over several months. We illustrate the instrument performance with the observations of archetypical objects for the different instrument modes. Examples include the Galactic Center supermassive black hole and its fast orbiting star S2 for phase referenced dual beam observations and infrared wavefront sensing, the High Mass X-Ray Binary BP Cru and the Active Galactic Nucleus of PDS 456 for few {\mu}as spectro-differential astrometry, the T Tauri star S CrA for a spectro-differential visibility analysis, {\xi} Tel and 24 Cap for high accuracy visibility observations, and {\eta} Car for interferometric imaging with GRAVITY., Comment: Accepted for publication in A&A, 23 pages, 23 figures, corresponding author: F. Eisenhauer

Published
2017
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5. Planet Formation Imager (PFI): science vision and key requirements

Author

Ridgway Steve, Regaly Zsolt, Kral Quentin, Gandhi Poshak, Packham Chris, Tristram Konrad R. W., Baruteau Clement, Tuthill Peter, Mordasini Chris, Matter Alexis, A. Pierens, Duchene Gaspard, Olofsson Johan, Ilee John, Bitsch Bertram, Wittkowski Markus, Pinte Christophe, Meru Farzana, Armitage Phil, Chiavassa Andrea, Berger Jean-Philippe, Millour Florentin, Buscher David, Rosotti Giovanni P., Zhao Ming, Pott Joerg-Uwe, Wolf Sebastian, ten Brummelaar Theo, Bayo Amelia, Labadie Lucas, Morlok Andreas, Millan-Gabet Rafael, Kishimoto Makoto, Gallenne Alexandre, Ciardi David, Turner Neal, Gonzalez Jean-Francois, Vasisht Gautam, Monnier John D., Zhu Zhaohuan, Weigelt Gerd, Quiroga-Nunez Luis Henry, Kratter Kaitlin, Ramos Almeida Cristina, Juhasz Attila, Kley Wilhelm, Smith Michael, Espaillat Catherine, Alonso Herrero Almudena, Paladini Claudia, Pope Benjamin, Bate Matthew R., de Wit Willem-Jan, Harries Tim J., Lacour Sylvestre, Boyajian Tabetha, Petrov Romain, Paardekooper Sijme-Jan, Laughlin Greg, Nelson Richard P., Hoenig Sebastian, Pepper Joshua, Stassun Keivan, Jensen Eric L. N., Bonsor Amy, Kraus Stefan, Haniff Chris, Reynold Mark, Panic Olja, Sean N. Raymond, Masset Frederic, van Belle Gerard, Morbidelli Alessandro, Kane Stephen R., Ireland Michael J., Surdej Jean, Oudmaijer Rene, Benisty Myriam, Micromotive GmbH, Mainz, Germany, Université Paris Diderot - Paris 7 (UPD7), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université libre de Bruxelles (ULB), The Breakthrough Breast Cancer Research Centre, Institute of cancer research, Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), foreign laboratories (FL), CERN [Genève], Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), 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, 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), Department of Materials Science and Engineering, Institute of Ceramics and Glass-Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Pontifical Catholic University of Paraná (PUCPR), Pontifical Catholic University of Paraná, UNESCO Chinese Center of Marine Biotechnology, Ocean University of China, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), École Supérieure Polytechnique de Dakar (ESP), Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD), ECLIPSE 2016, 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), The Samuel Roberts Noble Foundation, Max-Planck-Institut für Radioastronomie (MPIFR), LT2C, Laboratoire Telecom Claude Chappe (LT2C), Université Jean Monnet [Saint-Étienne] (UJM)-Ecole d'ingenieurs Telecom Saint Etienne-Université Jean Monnet [Saint-Étienne] (UJM)-Ecole d'ingenieurs Telecom Saint Etienne, NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), Universidad de Concepción [Chile], European Southern Observatory (ESO), Department of Physics, Durham University, Durham University, GRI-CEL, National Optical Astronomy Observatory (NOAO), Sydney Institute for Astronomy (SIfA), The University of Sydney, 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), Lund Observatory, Lund University [Lund], Malbet, Fabien, Creech-Eakman, Michelle J., Tuthill, Peter G., University of Exeter, Department of Astronomy, University of Michigan, Australian National University (ANU), University of California [Berkeley] (UC Berkeley), University of California (UC), Boston University [Boston] (BU), University of Southampton, Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), University of Bern, Instituto de Fisica y Astronomia [Valparaiso], Universidad de Valparaiso [Chile], Vanderbilt University [Nashville], Jet Propulsion Laboratory, California Institute of Technology (JPL), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Astrophysical Sciences, Princeton University, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, University of Kiel, Pennsylvania State University, Department of Astronomy & Astrophysics, Institut für Planetologie [Münster], Westfälische Wilhelms-Universität Münster = University of Münster (WWU), San Francisco State University (SFSU), University of Arizona, Yale University [New Haven], Lehigh University [Bethlehem], Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universität zu Köln = University of Cologne, Queen Mary University of London (QMUL), Georgia State University, Atlanta, Georgia State University, University System of Georgia (USG)-University System of Georgia (USG), University of Leeds, University of Tübingen, University of Oxford, Swarthmore College, University of Kent, Sterrewacht Leiden, Universiteit Leiden, Joint Institute for VLBI ERIC, Dwingeloo (JIVE), European Southern Observatory [Santiago] (ESO), Instituto de Astrofisica de Canarias (IAC), University of Cantabria, Santander, University of Madrid, The University of Texas at San Antonio (UTSA), Kyoto Sangyo University, Max Planck Institute for Astronomy (MPIA), University of Liege, Liege, Belgium, Observatoire de Paris, Université Paris sciences et lettres (PSL), Lowell Observatory [Flagstaff], JILA, NIST, and Department of Physics, University of Colorado, 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), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Institut de Mathématiques de Toulouse UMR5219 (IMT), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université Libre de Bruxelles [Bruxelles] (ULB), Aix Marseille Université (AMU)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institute of Ceramics and Glass-Friedrich Alexander University [Erlangen-Nürnberg], Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), École Supérieure Polytechnique - Université Cheikh Anta DIOP de Dakar (ESP - UCAD), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Samuel Roberts Noble Foundation, Inc., National Optical Astronomical Observatory (NOAO), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU)-Institute of Ceramics and Glass, Pontifícia Universidade Católica do Paraná (PUCPR), Université Jean Monnet - Saint-Étienne (UJM)-Ecole d'ingenieurs Telecom Saint Etienne-Université Jean Monnet - Saint-Étienne (UJM)-Ecole d'ingenieurs Telecom Saint Etienne, Universidad de Concepción - University of Concepcion [Chile], Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), 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 de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Computer science, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, 01 natural sciences, Astrobiology, 010309 optics, Planet, extrasolar planets, 0103 physical sciences, planet formation, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, high angular resolution imaging, Earth and Planetary Astrophysics (astro-ph.EP), protoplanetary disks, Planetary system, interferometry, Exoplanet, 13. Climate action, Hill sphere, Systems architecture, Key (cryptography), Astrophysics::Earth and Planetary Astrophysics, Protoplanet, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Planet Formation Imager (PFI) project aims to provide a strong scientific vision for ground-based optical astronomy beyond the upcoming generation of Extremely Large Telescopes. We make the case that a breakthrough in angular resolution imaging capabilities is required in order to unravel the processes involved in planet formation. PFI will be optimised to provide a complete census of the protoplanet population at all stellocentric radii and over the age range from 0.1 to about 100 Myr. Within this age period, planetary systems undergo dramatic changes and the final architecture of planetary systems is determined. Our goal is to study the planetary birth on the natural spatial scale where the material is assembled, which is the "Hill Sphere" of the forming planet, and to characterise the protoplanetary cores by measuring their masses and physical properties. Our science working group has investigated the observational characteristics of these young protoplanets as well as the migration mechanisms that might alter the system architecture. We simulated the imprints that the planets leave in the disk and study how PFI could revolutionise areas ranging from exoplanet to extragalactic science. In this contribution we outline the key science drivers of PFI and discuss the requirements that will guide the technology choices, the site selection, and potential science/technology tradeoffs., Comment: 13 pages, 5 figures, Proceedings of SPIE 2016

Published
2016
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6. Mass Losing Asymptotic Giant Branch Stars and Supergiants

Author

Whitelock, Patricia A., Boyer, Martha, Höfner, Susanne, Wittkowski, Markus, Zijlstra, Albert A., and Feiden, Gregory A.

Subjects
stellar parameters, FOS: Physical sciences, interferometry, binary stars, radio, models, Astrophysics - Solar and Stellar Astrophysics, Supergiants, infrared, Astrophysics::Solar and Stellar Astrophysics, pulsation, dust, Astrophysics::Earth and Planetary Astrophysics, AGB stars, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

This paper presents a summary of four invited and twelve contributed presentations on asymptotic giant branch stars and red supergiants, given over the course of two afternoon splinter sessions at the 19th Cool Stars Workshop. It highlights both recent observations and recent theory, with some emphasis on high spatial resolution, over a wide range of wavelengths. Topics covered include 3D models, convection, binary interactions, mass loss, dust formation and magnetic fields., Comment: To appear in the proceedings of the 19th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun; 19 pages and 20 figures

Published
2016
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7. The potential of near-infrared high-resolution studies on the field of galaxies in the young universe

Author

Wittkowski, Markus

Subjects
Astrophysics (astro-ph), Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

So far, high resolution techniques on the one hand provide morphological information on bright nearby objects. On the other hand, telescopes with large collecting areas allow us to detect very faint and distant objects, but not to obtain a spatial resolution which is sufficient for detailed morphological studies. Currently, the construction of large optical and infrared interferometers like the Keck Interferometer, the Very Large Telescope Interferometer (VLTI) and the Large Binocular Telescope Interferometer (LBTI) is in progress. These instruments will simultaneously provide larger collecting areas and higher spatial resolutions than current instruments. Thus, they might enable for the first time near-infrared studies of galaxies in the young universe with an absolute spatial resolution as available today only for the closest galaxies. Using recent results in the field of high resolution studies of nearby galaxies, a rough idea of what might be expected to be observed is given. The concepts of the forthcoming interferometers is reviewed and technical aspects that are essential for observations of distant galactic centers are discussed. An outlook is given on which observational tasks can be addressed to these instruments and how the results will increase our knowledge in the field of the evolution of galaxies and the universe., Comment: 9 pages, to appear in proceedings of JSPS/DFG Japan-German Seminar 2001 "Studies of Galaxies in the Young Universe with New Generation Telescopes", July 24-28, Sendai, Japan

Published
2001
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8. Tomography of evolved star atmospheres

Author

Kravchenko, Kateryna, Van Eck, Sophie, Chiavassa, Andréa, Jorissen, Alain, Godefroid, Michel, Perrin, Guy, Wittkowski, Markus, and Freytag, Bernd

Subjects
Star atmospheres, spectroscopy, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, interferometry, Red supergiant stars, Asymptotic giant branch stars, Astrophysics - Solar and Stellar Astrophysics, radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysique, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Cool giant and supergiant stars are among the largest and most luminous stars in the Universe and, therefore, dominate the integrated light of their host galaxies. These stars were extensively studied during last few decades, however their relevant properties like photometric variability and mass loss are still poorly constrained. Understanding of these properties is crucial in the context of a broad range of astrophysical questions including chemical enrichment of the Universe, supernova progenitors, and the extragalactic distance scale. Atmospheres of giant and supergiant stars are characterized by complex dynamics due to different interacting processes, such as convection, pulsation, formation of molecules and dust, and the development of mass loss. Current 1D/3D dynamical model atmospeheres are able to simulate these processes and produce a good agreement with the observed spectral features of evolved stars. However, the models lack constraints and need to be confronted to observables. Dynamical processes in stellar atmospheres impact the formation of spectral lines producing their asymmetries and Doppler shifts. Thus, by studying the line-profile variations on spatial and temporal scales it is possible to reconstruct atmospheric motions in evolved stars. As will be shown in this thesis, a tomographic method is an ideal technique for this purpose. The tomographic method is based on construction and cross-correlation of spectral templates (masks) with observed or synthetic stellar spectra in order to recover velocity fields at different optical depths in the stellar atmosphere.The first part of the thesis further improves the original implementation of the tomographic method. This improvement involves the computation of the contribution function in order to correctly determine an optical depth of formation of spectral lines. The tomographic method is, then, fully validated by applying it to a stellar convection simulation of a red supergiant star and correctly recovering its velocity field throughout the atmosphere. The second part of the thesis applies the tomographic method to the red supergiant star μ Cep in order to constrain its atmospheric motions and relate them to photometric variability. A phase lag (hysteresis) between the effective temperature and the radial velocity variations is revealed with timescales of a few hundred days, similar to photometric ones. A comparison to a stellar convection simulation of a red supergiant star indicates that hysteresis loops are linked to the stochastic shocks generated and shaped by the underlying large-scale convection and may be responsible for photometric variations in μ Cep. The third part of the thesis applies the tomographic method to spectro-interferometric observations of the Mira-type star S Ori. The uniform-disk angular diameters measured at wavelengths contributing to the tomographic masks increase with decrease of an optical depth probed by the masks. This validates the capability of the tomographic method to probe distinct geometrical depths in the stellar atmosphere. The last part of the thesis applies the tomograhic method to the Mira-type star RY Cep and compares the results to those obtained for μ Cep in this thesis. The comparison reveals differences in their behavior in the temperature-velocity plane pointing to the posibility to differentiate between Mira-type and red supergiant stars from their spectroscopic signatures., Doctorat en Sciences, info:eu-repo/semantics/nonPublished

Published
2022
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