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1. First VLTI/GRAVITY Observations of HIP 65426 b: Evidence for a Low or Moderate Orbital Eccentricity

Author

Sarah Blunt, W. O. Balmer, J. J. Wang, S. Lacour, S. Petrus, G. Bourdarot, J. Kammerer, N. Pourré, E. Rickman, J. Shangguan, T. Winterhalder, R. Abuter, A. Amorim, R. Asensio-Torres, M. Benisty, J.-P. Berger, H. Beust, A. Boccaletti, A. Bohn, M. Bonnefoy, H. Bonnet, W. Brandner, F. Cantalloube, P. Caselli, B. Charnay, G. Chauvin, A. Chavez, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé du Foresto, A. Cridland, R. Dembet, A. Drescher, and G. Duvert

Subjects
Astronomy
Abstract

Giant exoplanets have been directly imaged over orders of magnitude of orbital separations, prompting theoretical and observational investigations of their formation pathways. In this paper, we present new VLTI/GRAVITY astrometric data of HIP 65426 b, a cold, giant exoplanet which is a particular challenge for most formation theories at a projected separation of 92 au from its primary. Leveraging GRAVITY's astrometric precision, we present an updated eccentricity posterior that disfavors large eccentricities. The eccentricity posterior is still prior dependent, and we extensively interpret and discuss the limits of the posterior constraints presented here. We also perform updated spectral comparisons with self-consistent forward-modeled spectra, finding a best-fit ExoREM model with solar metallicity and C/O = 0.6. An important caveat is that it is difficult to estimate robust errors on these values, which are subject to interpolation errors as well as potentially missing model physics. Taken together, the orbital and atmospheric constraints paint a preliminary picture of formation inconsistent with scattering after disk dispersal. Further work is needed to validate this interpretation. Analysis code used to perform this work is available on GitHub: https://github.com/sblunt/hip65426.

Published
2023
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2. VLTI/GRAVITY Provides Evidence the Young, Substellar Companion HD 136164 Ab Formed Like a 'Failed Star'

Author

William O. Balmer, L. Pueyo, S. Lacour, J. J. Wang, T. Stolker, J. Kammerer, N. Pourré, M. Nowak, E. Rickman, S. Blunt, A. Sivaramakrishnan, D. Sing, K. Wagner, G.-D. Marleau, A.-M. Lagrange, R. Abuter, A. Amorim, R. Asensio-Torres, J.-P. Berger, H. Beust, A. Boccaletti, A. Bohn, M. Bonnefoy, H. Bonnet, M. S. Bordoni, G. Bourdarot, W. Brandner, F. Cantalloube, P. Caselli, B. Charnay, G. Chauvin, A. Chavez, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé du Foresto, A. Cridland, R. Davies, R. Dembet, A. Drescher, G. Duvert, A. Eckart, F. Eisenhauer, N. M. Förster Schreiber, P. Garcia, R. Garcia Lopez, E. Gendron, R. Genzel, S. Gillessen, J. H. Girard, S. Grant, X. Haubois, G. Heißel, Th. Henning, S. Hinkley, S. Hippler, M. Houllé, Z. Hubert, L. Jocou, M. Keppler, P. Kervella, L. Kreidberg, N. T. Kurtovic, V. Lapeyrère, J.-B. Le Bouquin, P. Léna, D. Lutz, A.-L. Maire, F. Mang, A. Mérand, P. Mollière, C. Mordasini, D. Mouillet, E. Nasedkin, T. Ott, G. P. P. L. Otten, C. Paladini, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, D. C. Ribeiro, L. Rodet, Z. Rustamkulov, J. Shangguan, T. Shimizu, C. Straubmeier, E. Sturm, L. J. Tacconi, A. Vigan, F. Vincent, K. Ward-Duong, F. Widmann, T. Winterhalder, J. Woillez, S. Yazici, and the GRAVITY Collaboration

Subjects
Brown dwarfs, Substellar companion stars, Orbit determination, Orbits, Astronomy, QB1-991
Abstract

Young, low-mass brown dwarfs orbiting early-type stars, with low mass ratios ( q ≲ 0.01), appear to be intrinsically rare and present a formation dilemma: could a handful of these objects be the highest-mass outcomes of “planetary” formation channels (bottom up within a protoplanetary disk), or are they more representative of the lowest-mass “failed binaries” (formed via disk fragmentation or core fragmentation)? Additionally, their orbits can yield model-independent dynamical masses, and when paired with wide wavelength coverage and accurate system age estimates, can constrain evolutionary models in a regime where the models have a wide dispersion depending on the initial conditions. We present new interferometric observations of the 16 Myr substellar companion HD 136164 Ab (HIP 75056 Ab) made with the Very Large Telescope Interferometer (VLTI)/GRAVITY and an updated orbit fit including proper motion measurements from the Hipparcos–Gaia Catalog of Accelerations. We estimate a dynamical mass of 35 ± 10 M _J ( q ∼ 0.02), making HD 136164 Ab the youngest substellar companion with a dynamical mass estimate. The new mass and newly constrained orbital eccentricity ( e = 0.44 ± 0.03) and separation (22.5 ± 1 au) could indicate that the companion formed via the low-mass tail of the initial mass function. Our atmospheric fit to a SPHINX M-dwarf model grid suggests a subsolar C/O ratio of 0.45 and 3 × solar metallicity, which could indicate formation in a circumstellar disk via disk fragmentation. Either way, the revised mass estimate likely excludes bottom-up formation via core accretion in a circumstellar disk. HD 136164 Ab joins a select group of young substellar objects with dynamical mass estimates; epoch astrometry from future Gaia data releases will constrain the dynamical mass of this crucial object further.

Published
2024
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3. VLTI/GRAVITY Observations and Characterization of the Brown Dwarf Companion HD 72946 B

Author

William O. Balmer, Laurent Pueyo, Tomas Stolker, Henrique Reggiani, A.-L. Maire, S. Lacour, P. Mollière, M. Nowak, D. Sing, N. Pourré, S. Blunt, J. J. Wang, E. Rickman, J. Kammerer, Th. Henning, K. Ward-Duong, R. Abuter, A. Amorim, R. Asensio-Torres, M. Benisty, J.-P. Berger, H. Beust, A. Boccaletti, A. Bohn, M. Bonnefoy, H. Bonnet, G. Bourdarot, W. Brandner, F. Cantalloube, P. Caselli, B. Charnay, G. Chauvin, A. Chavez, E. Choquet, V. Christiaens, Y. Clénet, V. Coudé du Foresto, A. Cridland, R. Dembet, J. Dexter, A. Drescher, G. Duvert, A. Eckart, F. Eisenhauer, F. Gao, P. Garcia, R. Garcia Lopez, E. Gendron, R. Genzel, S. Gillessen, J. H. Girard, X. Haubois, G. Heißel, S. Hinkley, S. Hippler, M. Horrobin, M. Houllé, Z. Hubert, L. Jocou, M. Keppler, P. Kervella, L. Kreidberg, A.-M. Lagrange, V. Lapeyrère, J.-B. Le Bouquin, P. Léna, D. Lutz, J. D. Monnier, D. Mouillet, E. Nasedkin, T. Ott, G. P. P. L. Otten, C. Paladini, T. Paumard, K. Perraut, G. Perrin, O. Pfuhl, J. Rameau, L. Rodet, G. Rousset, Z. Rustamkulov, J. Shangguan, T. Shimizu, J. Stadler, O. Straub, C. Straubmeier, E. Sturm, L. J. Tacconi, E. F. van Dishoeck, A. Vigan, F. Vincent, S. D. von Fellenberg, F. Widmann, E. Wieprecht, E. Wiezorrek, T. Winterhalder, J. Woillez, S. Yazici, A. Young, The ExoGRAVITY Collaboration, and The GRAVITY Collaboration

Subjects
Brown dwarfs, L dwarfs, Interferometry, Long baseline interferometry, Optical interferometry, Orbit determination, Astrophysics, QB460-466
Abstract

Tension remains between the observed and modeled properties of substellar objects, but objects in binary orbits, with known dynamical masses, can provide a way forward. HD 72946 B is a recently imaged brown dwarf companion to a nearby, solar-type star. We achieve ∼100 μ as relative astrometry of HD 72946 B in the K band using VLTI/GRAVITY, unprecedented for a benchmark brown dwarf. We fit an ensemble of measurements of the orbit using orbitize! and derive a strong dynamical mass constraint M _B = 69.5 ± 0.5 M _Jup assuming a strong prior on the host star mass M _A = 0.97 ± 0.01 M _⊙ from an updated stellar analysis. We fit the spectrum of the companion to a grid of self-consistent BT-Settl-CIFIST model atmospheres, and perform atmospheric retrievals using petitRADTRANS . A dynamical mass prior only marginally influences the sampled distribution of effective temperature, but has a large influence on the surface gravity and radius, as expected. The dynamical mass alone does not strongly influence retrieved pressure–temperature or cloud parameters within our current retrieval setup. Independently of the cloud prescription and prior assumptions, we find agreement within ±2 σ between the C/O of the host (0.52 ± 0.05) and brown dwarf (0.43–0.63), as expected from a molecular cloud collapse formation scenario, but our retrieved metallicities are implausibly high (0.6–0.8) in light of the excellent agreement of the data with the solar-abundance model grid. Future work on our retrieval framework will seek to resolve this tension. Additional study of low surface gravity objects is necessary to assess the influence of a dynamical mass prior on atmospheric analysis.

Published
2023
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4. Constraining particle acceleration in Sgr A? with simultaneous GRAVITY, Spitzer, NuSTAR, and Chandra observations

Author

R. Abuter, A. Amorim, M. Bauböck, F. Baganoff, J. P. Berger, H. Boyce, H. Bonnet, W. Brandner, Y. Clénet, R. Davies, P. T. de Zeeuw, J. Dexter, Y. Dallilar, A. Drescher, A. Eckart, F. Eisenhauer, G. G. Fazio, N. M. Förster Schreiber, K. Foster, C. Gammie, P. Garcia, F. Gao, E. Gendron, R. Genzel, G. Ghisellini, S. Gillessen, M. A. Gurwell, M. Habibi, D. Haggard, C. Hailey, F. A. Harrison, X. Haubois, G. Heißel, T. Henning, and S. Hippler

Subjects
Astrophysics
Abstract

We report the time-resolved spectral analysis of a bright near-infrared and moderate X-ray flare of Sgr A⋆. We obtained light curves in the M, K, and H bands in the mid- and near-infrared and in the 2 − 8 keV and 2 − 70 keV bands in the X-ray. The observed spectral slope in the near-infrared band is νLν ∝ ν0.5 ± 0.2; the spectral slope observed in the X-ray band is νLν ∝ ν−0.7 ± 0.5. Using a fast numerical implementation of a synchrotron sphere with a constant radius, magnetic field, and electron density (i.e., a one-zone model), we tested various synchrotron and synchrotron self-Compton scenarios. The observed near-infrared brightness and X-ray faintness, together with the observed spectral slopes, pose challenges for all models explored. We rule out a scenario in which the near-infrared emission is synchrotron emission and the X-ray emission is synchrotron self-Compton. Two realizations of the one-zone model can explain the observed flare and its temporal correlation: one-zone model in which the near-infrared and X-ray luminosity are produced by synchrotron self-Compton and a model in which the luminosity stems from a cooled synchrotron spectrum. Both models can describe the mean spectral energy distribution (SED) and temporal evolution similarly well. In order to describe the mean SED, both models require specific values of the maximum Lorentz factor γmax, which differ by roughly two orders of magnitude. The synchrotron self-Compton model suggests that electrons are accelerated to γmax ∼ 500, while cooled synchrotron model requires acceleration up to γmax ∼ 5 × 104. The synchrotron self-Compton scenario requires electron densities of 1010 cm−3 that are much larger than typical ambient densities in the accretion flow. Furthermore, it requires a variation of the particle density that is inconsistent with the average mass-flow rate inferred from polarization measurements and can therefore only be realized in an extraordinary accretion event. In contrast, assuming a source size of 1 RS, the cooled synchrotron scenario can be realized with densities and magnetic fields comparable with the ambient accretion flow. For both models, the temporal evolution is regulated through the maximum acceleration factor γmax, implying that sustained particle acceleration is required to explain at least a part of the temporal evolution of the flare.

Published
2021
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5. The mass of β Pictoris c from β Pictoris b orbital motion

Author

Matthias Samland, Anne-Lise Maire, David Mouillet, Andreas Eckart, Valentin Christiaens, Julien Woillez, Sarah Blunt, K. Perraut, T. Paumard, T. Ott, Myriam Benisty, E. Nasedkin, A. Mérand, Z. Hubert, Stefan Hippler, Frank Eisenhauer, Roderick Dembet, Gilles Otten, F. H. Vincent, Pierre Léna, Jinyi Shangguan, Miriam Keppler, Ekkehard Wieprecht, G. Bourdarot, M. Houllé, Odele Straub, Alexander J. Bohn, M. Nowak, Felix Widmann, K. Ward-Duong, P. T. de Zeeuw, J.-B. Le Bouquin, Julia Stadler, T. Taro Shimizu, A. Boccaletti, David K. Sing, Ji Wang, Linda J. Tacconi, Arthur Vigan, Elodie Choquet, Jens Kammerer, Claudia Paladini, J. Rameau, R. J. García López, Xavier Haubois, E. Rickman, Guy Perrin, J. P. Berger, Wolfgang Brandner, Eric Gendron, G. Heißel, H. Bonnet, Laurent Jocou, A. Cridland, S. D. von Fellenberg, Pierre Kervella, R. Asensio-Torres, G. Rousset, O. Pfuhl, Erich Wiezorrek, M. Bonnefoy, Y. Clénet, Senol Yazici, R. Abuter, John D. Monnier, Laura Kreidberg, Paulo J. V. Garcia, Zafar Rustamkulov, Tomas Stolker, Gilles Duvert, Paul Mollière, H. Beust, Eckhard Sturm, António Amorim, Anne-Marie Lagrange, Paola Caselli, Christian Straubmeier, Th. Henning, G. Chauvin, Benjamin Charnay, Sylvestre Lacour, E. F. van Dishoeck, Jason Dexter, Stefan Gillessen, André Young, D. Lutz, V. Coudé du Foresto, R. Genzel, Feng Gao, J. H. Girard, Faustine Cantalloube, L. Rodet, Sasha Hinkley, A. Drescher, Vincent Lapeyrere, Laurent Pueyo, Matthew Horrobin, M. L. Bolzer, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), 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), MacoPharma, 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), Caltech Department of Astronomy [Pasadena], California Institute of Technology (CALTECH), Departamento de Astronomía, Universidad de Chile = University of Chile [Santiago] (UCHILE), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, European Southern Observatory (ESO), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Max-Planck-Institut für Astronomie (MPIA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Service de Pathologie respiratoire et allergologie [CHU Limoges], CHU Limoges, University of Auckland [Auckland], the GRAVITY Collaboration, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-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, 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), Harvard University-Smithsonian Institution, and Université de Genève = University of Geneva (UNIGE)

Subjects
Astrophysics - instrumentation and methods for astrophysics, planets and satellites: detection, 010504 meteorology & atmospheric sciences, Astrophysics, Astrophysics - Earth and planetary astrophysics, 01 natural sciences, High angular resolution, Planet, instrumentation: high angular resolution, 0103 physical sciences, Beta Pictoris, 10. No inequality, instrumentation: interferometers, 010303 astronomy & astrophysics, Instrumentation, 0105 earth and related environmental sciences, Orbital elements, Physics, Interferometers, Astronomy and Astrophysics, Astrometry, Exoplanet, Radial velocity, Detection, Space and Planetary Science, Orbital motion, Planets and satellites, Eccentricity (mathematics), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Aims.We aim to demonstrate that the presence and mass of an exoplanet can now be effectively derived from the astrometry of another exoplanet.Methods.We combined previous astrometry ofβPictoris b with a new set of observations from the GRAVITY interferometer. The orbital motion ofβPictoris b is fit using Markov chain Monte Carlo simulations in Jacobi coordinates. The inner planet,βPictoris c, was also reobserved at a separation of 96 mas, confirming the previous orbital estimations.Results.From the astrometry of planet b only, we can (i) detect the presence ofβPictoris c and (ii) constrain its mass to 10.04−3.10+4.53MJup. If one adds the astrometry ofβPictoris c, the mass is narrowed down to 9.15−1.06+1.08MJup. The inclusion of radial velocity measurements does not affect the orbital parameters significantly, but it does slightly decrease the mass estimate to 8.89−0.75+0.75MJup. With a semimajor axis of 2.68 ± 0.02 au, a period of 1221 ± 15 days, and an eccentricity of 0.32 ± 0.02, the orbital parameters ofβPictoris c are now constrained as precisely as those ofβPictoris b. The orbital configuration is compatible with a high-order mean-motion resonance (7:1). The impact of the resonance on the planets’ dynamics would then be negligible with respect to the secular perturbations, which might have played an important role in the eccentricity excitation of the outer planet.

Published
2021
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6. NAOMI: the adaptive optics system of the Auxiliary Telescopes of the VLTI

Author

E. Cottalorda, C. Heritier, F. Delplancke-Ströbele, S. Zúñiga-Fernández, S. Guieu, Javier Reyes, M. Seidel, Alexander Meister, Laurent Jocou, Johan Kosmalski, G. Santos Tomás, Oliver Pfuhl, Pierre Bourget, Marcos Suarez, Christophe Verinaud, J. L. Beuzit, Anthony Meilland, Philippe B. Gitton, Andreas Haimerl, J.-B. Le Bouquin, Eric Stadler, C. Frank, Christophe Dupuy, Lorenzo Pettazzi, Pascaline Darré, Xavier Haubois, Gérard Zins, Frédéric Gonté, Jaime Alonso, Bruno Lopez, R. Donaldson, Peter Krempl, H. Bonnet, Pavel Shchekaturov, Johann Kolb, Frank Eisenhauer, Pablo Gutierrez, Thibaut Guerlet, Paul Lilley, Julien Woillez, J. P. Berger, Gerhard Fischer, M. Todorovic, Sebastien Egner, A. Mérand, Thibaut Moulin, Luis Caniguante, Christian Stephan, J. P. Kirchbauer, Luigi Andolfato, Guillermo Valdes, N. Hubin, D. Phan, Eloy Fuenteseca, Stewart McLay, M. Riedel, Isabelle Percheron, A. Delboulbe, Jerome Paufique, W. Pirani, Christian Schmid, Christian Soenke, J. Dupeyron, Jose Abad, Andrew Rakich, M. Le Louarn, Pablo Barriga, Stefan Huber, P. Haguenauer, Paul Jolley, G. Bourdarot, E. Aller Carpentier, R. Brast, Nicolas Schuhler, B. Delabre, Reinhold J. Dorn, Roderick Dembet, Sylvain Rochat, Roberto Abuter, Yves Magnard, J. Quentin, Luca Pasquini, R. Ridings, European Southern Observatory (ESO), 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]), Centre Spatial Universitaire de Grenoble ( CSUG), CRLCC Eugène Marquis (CRLCC), 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), and 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)

Subjects
Physics, Wavefront, Coupling, Very Large Telescope, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Tracking (particle physics), 01 natural sciences, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 010309 optics, Interferometry, Optics, Space and Planetary Science, 0103 physical sciences, Astronomical seeing, Astrophysics::Solar and Stellar Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, business, Adaptive optics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics
Abstract

The tip-tilt stabilisation system of the 1.8 m Auxiliary Telescopes of the Very Large Telescope Interferometer was never dimensioned for robust fringe tracking, except when atmospheric seeing conditions are excellent. Increasing the level of wavefront correction at the telescopes is expected to improve the coupling into the single-mode fibres of the instruments, and enable robust fringe tracking even in degraded conditions. We deployed a new adaptive optics module for interferometry (NAOMI) on the Auxiliary Telescopes. We present its design, performance, and effect on the observations that are carried out with the interferometric instruments., Comment: 10 pages, 18 figures, 2 tables, A&A forthcoming

Published
2019
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7. GRAVITY chromatic imaging of η Car's core. Milliarcsecond resolution imaging of the wind-wind collision zone (Brγ, He I)

Author

S. Kellner, Pierre Kervella, Faustine Cantalloube, Johana Panduro, Magdalena Lippa, V. Coudé du Foresto, Y. Clénet, R. Abuter, G. Avila, Matteo Accardo, Konrad R. W. Tristram, Dan Popovic, Alejandra Rosales, A. Buron, R. Genzel, C. Deen, Laurent Jocou, Markus Schöller, T. Ott, H. Bonnet, P. Fédou, Frank Eisenhauer, R. van Boekel, Stefan Hippler, André Müller, Pierre Léna, Thibaut Moulin, Julien Woillez, L. Pallanca, Ekkehard Wieprecht, P.-O. Petrucci, N. Hubin, Leander Mehrgan, Sylvestre Lacour, Markus Wittkowski, Vincent Lapeyrere, Christian A. Hummel, M. Haug, Eckhard Sturm, Frederic Derie, Thanh Phan Duc, Sarah Kendrew, Burkhard Wolff, Mario Kiekebusch, Nicolas Blind, Andreas Kaufer, W. J. de Wit, Feng Gao, C. Collin, Silvia Scheithauer, L. Kern, Roderick Dembet, Matthew Horrobin, J.-U. Pott, Stefan Gillessen, Johann Kolb, Narsireddy Anugu, R.-R. Rohloff, M. Riquelme, J. Sanchez-Bermudez, Andreas Eckart, J. Moreno-Ventas, R. Brast, Z. Hubert, Isabelle Percheron, M. Mellein, F. Delplancke-Ströbele, M. Karl, Udo Neumann, Imke Wank, Rainer Lenzen, Odele Straub, Michael Esselborn, Armin Huber, J.-B. Le Bouquin, Ralf Klein, Juan-Luis Ramos, Erich Wiezorrek, Samuel Lévêque, K. Perraut, Frédéric Cassaing, C. E. Garcia Dabo, F. Müller, P. M. Plewa, Ewald Müller, N. Ventura, F. Chapron, Gerd Weigelt, M. Ebert, Martin Kulas, M. Wiest, Elodie Choquet, Luca Pasquini, A. Caratti o Garatti, A. Pflüger, T. de Zeeuw, Guy Perrin, Myriam Benisty, Yves Magnard, Joachim M. Bestenlehner, S. Oberti, António Amorim, Nicolas Schuhler, B. Lazareff, Paulo J. V. Garcia, Jason Dexter, Christian Straubmeier, Th. Henning, Jason Spyromilio, F. H. Vincent, A. Mérand, Senol Yazici, Felix Widmann, C. Rau, Pierre Bourget, R. J. García López, Xavier Haubois, Eric Gendron, Gérard Zins, G. Rousset, Andres J. Ramirez, Gilles Duvert, T. Paumard, Lieselotte Jochum, Idel Waisberg, F. Haussmann, O. Pfuhl, Sebastian Rabien, G. Rodríguez-Coira, Gerd Jakob, J. P. Berger, Wolfgang Brandner, D. Ziegler, and Marcos Suarez

Subjects
Physics, 010308 nuclear & particles physics, Binary number, Astronomy and Astrophysics, Astrophysics, Collision, 01 natural sciences, Galaxy, Wavelength, 13. Climate action, Space and Planetary Science, Angular diameter, 0103 physical sciences, Radiative transfer, Chromatic scale, 010303 astronomy & astrophysics, Cavity wall
Abstract

Context. η Car is one of the most intriguing luminous blue variables in the Galaxy. Observations and models of the X-ray, ultraviolet, optical, and infrared emission suggest a central binary in a highly eccentric orbit with a 5.54 yr period residing in its core. 2D and 3D radiative transfer and hydrodynamic simulations predict a primary with a dense and slow stellar wind that interacts with the faster and lower density wind of the secondary. The wind-wind collision scenario suggests that the secondary’s wind penetrates the primary’s wind creating a low-density cavity in it, with dense walls where the two winds interact. However, the morphology of the cavity and its physical properties are not yet fully constrained. Aims. We aim to trace the inner ∼5–50 au structure of η Car’s wind-wind interaction, as seen through Brγ and, for the first time, through the He I 2s-2p line. Methods. We have used spectro-interferometric observations with the K-band beam-combiner GRAVITY at the VLTI. The analyses of the data include (i) parametrical model-fitting to the interferometric observables, (ii) a CMFGEN model of the source’s spectrum, and (iii) interferometric image reconstruction. Results. Our geometrical modeling of the continuum data allows us to estimate its FWHM angular size close to 2 mas and an elongation ratio ϵ = 1.06 ± 0.05 over a PA = 130° ± 20°. Our CMFGEN modeling of the spectrum helped us to confirm that the role of the secondary should be taken into account to properly reproduce the observed Brγ and He I lines. Chromatic images across the Brγ line reveal a southeast arc-like feature, possibly associated to the hot post-shocked winds flowing along the cavity wall. The images of the He I 2s-2p line served to constrain the 20 mas (∼50 au) structure of the line-emitting region. The observed morphology of He I suggests that the secondary is responsible for the ionized material that produces the line profile. Both the Brγ and the He I 2s-2p maps are consistent with previous hydrodynamical models of the colliding wind scenario. Future dedicated simulations together with an extensive interferometric campaign are necessary to refine our constraints on the wind and stellar parameters of the binary, which finally will help us predict the evolutionary path of η Car.

Published
2018

8. The close circumstellar environment of Betelgeuse

Author

Guy Perrin, Andrea Chiavassa, Michel Aurière, Sylvestre Lacour, Pierre Kervella, P. Mathias, J. P. Berger, Xavier Haubois, M. Montargès, A. López-Ariste, S. T. Ridgway, J.-B. Le Bouquin, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), 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), Laboratoire Franco-Chilien d'Astronomie (LFCA), Universidad de Concepción [Chile]-Pontificia Universidad Católica de Chile (UC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Universidad de Chile, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-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), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées, National Optical Astronomical Observatory (NOAO), European Southern Observatory (ESO), PHASE, the high-angular resolution partnership between ONERA, Observatoire de Paris, CNRS, and University Denis Diderot Paris 7, Programme National de Physique Stellaire (PNPS) of CNRS/INSU, France, NASA - Contrat : HST-GO-12610.001-A, 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), 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), 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]), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), 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), 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), National Optical Astronomy Observatory (NOAO), Universidad de Chile = University of Chile [Santiago] (UCHILE)-Pontificia Universidad Católica de Chile (UC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Universidad de Concepción - University of Concepcion [Chile], 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), 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), 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, Centre National de la Recherche Scientifique (CNRS)-Universidad de Concepción [Chile]-Pontificia Universidad Católica de Chile (UC)-Universidad de Chile-Institut national des sciences de l'Univers (INSU - CNRS), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Convection, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, individual: Betelgeuse, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Red supergiant, 010303 astronomy & astrophysics, infrared: stars, Solar and Stellar Astrophysics (astro-ph.SR), Convection cell, Betelgeuse, Physics, Photosphere, 010308 nuclear & particles physics, Astronomy and Astrophysics, supergiants, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], stars: imaging, Interstellar medium, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, techniques: interferometric, Astrophysics::Earth and Planetary Astrophysics, stars: mass-loss
Abstract

Context. The mass-loss mechanism of cool massive evolved stars is poorly understood. The proximity of Betelgeuse makes it an appealing target to study its atmosphere, map the shape of its envelope, and follow the structure of its wind from the photosphere out to the interstellar medium. Aims. A link is suspected between the powerful convective motions in Betelgeuse and its mass loss. We aim to constrain the spatial structure and temporal evolution of the convective pattern on the photosphere and to search for evidence of this link. Methods. We report new interferometric observations in the infrared H band using the VLTI/PIONIER instrument. We monitored the photosphere of Betelgeuse between 2012 January and 2014 November to look for evolutions that may trigger the outflow. Results. Our interferometric observations at low spatial frequencies are compatible with the presence of a hot spot on the photosphere that has a characteristic width of one stellar radius. It appears to be superposed on the smaller scale convective pattern. In the higher spatial frequency domain, we observe a significant difference between the observations and the predictions of 3D hydrodynamical simulations. Conclusions. We bring new evidence for the presence of a convective pattern in the photosphere of red supergiants. The inferred hot spot is probably the top of a giant convection cell although an asymmetric extension of the star cannot be excluded by these interferometric observations alone. The properties of the observed surface features show a stronger contrast and inhomogeneity as predicted by 3D radiative hydrodynamical simulations. We propose that the large observed feature is modifying the signature of the convective pattern at the surface of the star in a way that simulations cannot reproduce., Comment: 11 pages, 4 figures, 2016, A&A, 588, A130

Published
2016
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9. 2D and 3D MALDI-imaging: Conceptual strategies for visualization and data mining

Author

J. P. Berger, Wolfgang Dreher, Bernd M. Fischer, Jan Hendrik Kobarg, Jan Strehlow, Stefan Wirtz, Peter Maass, Stefan Heldmann, Herbert Thiele, Dennis Trede, Janina Oetjen, and Publica

Subjects
MALDI imaging, Scanner, Computer science, business.industry, Biophysics, Analytical chemistry, Image registration, Biochemistry, Analytical Chemistry, Visualization, Imaging, Three-Dimensional, Data visualization, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Data analysis, Data Mining, Computer vision, Segmentation, Artificial intelligence, business, Cluster analysis, Molecular Biology, Chromatography, Liquid
Abstract

3D imaging has a significant impact on many challenges in life sciences, because biology is a 3-dimensional phenomenon. Current 3D imaging-technologies (various types MRI, PET, SPECT) are labeled, i.e. they trace the localization of a specific compound in the body. In contrast, 3D MALDI mass spectrometry-imaging (MALDI-MSI) is a label-free method imaging the spatial distribution of molecular compounds. It complements 3D imaging labeled methods, immunohistochemistry, and genetics-based methods. However, 3D MALDI-MSI cannot tap its full potential due to the lack of statistical methods for analysis and interpretation of large and complex 3D datasets. To overcome this, we established a complete and robust 3D MALDI-MSI pipeline combined with efficient computational data analysis methods for 3D edge preserving image denoising, 3D spatial segmentation as well as finding colocalized m/z values, which will be reviewed here in detail. Furthermore, we explain, why the integration and correlation of the MALDI imaging data with other imaging modalities allows to enhance the interpretation of the molecular data and provides visualization of molecular patterns that may otherwise not be apparent. Therefore, a 3D data acquisition workflow is described generating a set of 3 different dimensional images representing the same anatomies. First, an in-vitro MRI measurement is performed which results in a three-dimensional image modality representing the 3D structure of the measured object. After sectioning the 3D object into N consecutive slices, all N slices are scanned using an optical digital scanner, enabling for performing the MS measurements. Scanning the individual sections results into low-resolution images, which define the base coordinate system for the whole pipeline. The scanned images conclude the information from the spatial (MRI) and the mass spectrometric (MALDI-MSI) dimension and are used for the spatial three-dimensional reconstruction of the object performed by image registration techniques. Different strategies for automatic serial image registration applied to MS datasets are outlined in detail. The third image modality is histology driven, i.e. a digital scan of the histological stained slices in high-resolution. After fusion of reconstructed scan images and MRI the slice-related coordinates of the mass spectra can be propagated into 3D-space. After image registration of scan images and histological stained images, the anatomical information from histology is fused with the mass spectra from MALDI-MSI. As a result of the described pipeline we have a set of 3 dimensional images representing the same anatomies, i.e. the reconstructed slice scans, the spectral images as well as corresponding clustering results, and the acquired MRI. Great emphasis is put on the fact that the co-registered MRI providing anatomical details improves the interpretation of 3D MALDI images. The ability to relate mass spectrometry derived molecular information with in vivo and in vitro imaging has potentially important implications. This article is part of a Special Issue entitled: Computational Proteomics in the Post-Identification Era. Guest Editors: Martin Eisenacher and Christian Stephan.

Published
2014

10. MRI-compatible pipeline for three-dimensional MALDI imaging mass spectrometry using PAXgene fixation

Author

Stefan Wirtz, Axel Walch, Herbert Thiele, Michael Gottschalk, Michaela Aichler, Peter Maass, Michael Becker, Stefan Heldmann, Dennis Trede, Theodore Alexandrov, Stefan Schiffler, Janina Oetjen, Jan Hendrik Kobarg, J. P. Berger, Jan Strehlow, and Publica

Subjects
Proteomics, MALDI imaging, Proteome, Biophysics, Analytical chemistry, Biology, Kidney, 01 natural sciences, Biochemistry, Mice, 03 medical and health sciences, Microscopy, medicine, Animals, Segmentation, Databases, Protein, 030304 developmental biology, Fixation (histology), 0303 health sciences, medicine.diagnostic_test, 010401 analytical chemistry, Volume rendering, Magnetic resonance imaging, Magnetic Resonance Imaging, 0104 chemical sciences, Visualization, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Biomedical engineering
Abstract

MALDI imaging mass spectrometry (MALDI-imaging) has emerged as a spatially-resolved label-free bioanalytical technique for direct analysis of biological samples and was recently introduced for analysis of 3D tissue specimens. We present a new experimental and computational pipeline for molecular analysis of tissue specimens which integrates 3D MALDI-imaging, magnetic resonance imaging (MRI), and histological staining and microscopy, and evaluate the pipeline by applying it to analysis of a mouse kidney. To ensure sample integrity and reproducible sectioning, we utilized the PAXgene fixation and paraffin embedding and proved its compatibility with MRI. Altogether, 122 serial sections of the kidney were analyzed using MALDI-imaging, resulting in a 3D dataset of 200 GB comprised of 2 million spectra. We show that elastic image registration better compensates for local distortions of tissue sections. The computational analysis of 3D MALDI-imaging data was performed using our spatial segmentation pipeline which determines regions of distinct molecular composition and finds m/z-values co-localized with these regions. For facilitated interpretation of 3D distribution of ions, we evaluated isosurfaces providing simplified visualization. We present the data in a multimodal fashion combining 3D MALDI-imaging with the MRI volume rendering and with light microscopic images of histologically stained sections. Biological significance Our novel experimental and computational pipeline for 3D MALDI-imaging can be applied to address clinical questions such as proteomic analysis of the tumor morphologic heterogeneity. Examining the protein distribution as well as the drug distribution throughout an entire tumor using our pipeline will facilitate understanding of the molecular mechanisms of carcinogenesis. This article is part of a Special Issue entitled: From Genome to Proteome: Open Innovations.

Published
2013

11. GRAVITY: a four-telescope beam combiner instrument for the VLTI

Author

Laurent Jocou, Markus Schöller, R.-R. Rohloff, Sylvestre Lacour, Xavier Haubois, Philippe B. Gitton, Andreas Eckart, Guy Perrin, Christian Straubmeier, Th. Henning, Constanza Araujo-Hauck, H. Bartko, Frank Eisenhauer, Stefan Hippler, Pedro Carvas, O. Pfuhl, D. Moch, A. Gräter, Pierre Kervella, Nadia Kudryavtseva, Sebastian Rabien, M. Haug, Rainer Lenzen, Y. Clénet, Kevin Wagner, S. Kellner, M. Wiest, Damian Moratschke, Senol Yazici, P. Fédou, Arnaud Sevin, Stefan Gillessen, J. M. Rees, C. Collin, Gérard Rousset, F. Chapron, Juan-Luis Ramos, M. Thiel, António Amorim, D. Ziegler, Frédéric Gonté, Reiner Hofmann, A. Nolot, K. Perraut, Reinhard Genzel, Elodie Choquet, Ralf Klein, Vianak Naranjo, Eric Gendron, Pierre Léna, Pierre Haguenauer, Udo Neumann, Thibaut Moulin, T. Paumard, Harald Baumeister, J. P. Berger, Wolfgang Brandner, Sebastian Fischer, D. Rouan, Werner Laun, J. Lima, Vincent Lapeyrere, Frédéric Cassaing, 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), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Ingénieurs, Techniciens et Administratifs

Subjects
Physics, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy, Field of view, Astrometry, Metrology, law.invention, Black hole, Telescope, Interferometry, law, Magnitude (astronomy), Astrophysics::Solar and Stellar Astrophysics, Adaptive optics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics
Abstract

GRAVITY is an adaptive optics assisted Beam Combiner for the second generation VLTI instrumentation. The instrument will provide high-precision narrow-angle astrometry and phase-referenced interferometric imaging in the astronomical K-band for faint objects. We describe the wide range of science that will be tackled with this instrument, highlighting the unique capabilities of the VLTI in combination with GRAVITY. The most prominent goal is to observe highly relativistic motions of matter close to the event horizon of Sgr A*, the massive black hole at center of the Milky Way. We present the preliminary design that fulfils the requirements that follow from the key science drivers: It includes an integrated optics, 4-telescope, dual feed beam combiner operated in a cryogenic vessel; near-infrared wavefrontsensing adaptive optics; fringe-tracking on secondary sources within the field of view of the VLTI and a novel metrology concept. Simulations show that 10 {\mu}as astrometry within few minutes is feasible for a source with a magnitude of mK = 15 like Sgr A*, given the availability of suitable phase reference sources (mK = 10). Using the same setup, imaging of mK = 18 stellar sources in the interferometric field of view is possible, assuming a full night of observations and the corresponding UV coverage of the VLTI., Comment: 20 pages, Proceedings SPIE Astronomical Telescopes and Instrumentation Conference 2010

Published
2010
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12. Strong near-infrared emission in the sub-AU disk of the Herbig Ae star HD163296: evidence for refractory dust?

Author

A. Mérand, A. Natta, Gilles Duvert, Leonardo Testi, Fabien Malbet, Johan Olofsson, J-B. LeBouquin, Stefan Kraus, Martin Vannier, J.-P. Berger, A. Isella, F. Massi, S. Robbe-Dubois, Myriam Benisty, Gerd Weigelt, 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), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), European Southern Observatory, European Southern Observatory (ESO), Max-Planck-Institut für Radioastronomie (MPIFR), Laboratoire Hippolyte Fizeau (FIZEAU), 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), and Faure, Alexandre

Subjects
Physics, 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Near-infrared spectroscopy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Star (graph theory), [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, K band, Phase (matter), 0103 physical sciences, Closure phase, Spectral energy distribution, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, 010303 astronomy & astrophysics, Refractory (planetary science), ComputingMilieux_MISCELLANEOUS, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract

We present new long-baseline spectro-interferometric observations of the HerbigAe star HD163296 obtained in the H and K bands with the AMBER instrument at VLTI. The observations cover a range of spatial resolutions between 3 and 12 milli-arcseconds, with a spectral resolution of ~30. With a total of 1481 visibilities and 432 closure phases, they result in the best (u,v) coverage achieved on a young star so far. The circumstellar material is resolved at the sub-AU spatial scale and closure phase measurements indicate a small but significant deviation from point-symmetry. We discuss the results assuming that the near-infrared excess in HD163296 is dominated by the emission of a circumstellar disk. A successful fit to the spectral energy distribution, near-infrared visibilities and closure phases is found with a model where a dominant contribution to the H and K band emissions arises from an optically thin, smooth and point-symmetric region extending from about 0.1 to 0.45 AU. At the latter distance from the star, silicates condense, the disk becomes optically thick and develops a puffed-up rim, whose skewed emission can account for the non-zero closure phases. We discuss the nature of the inner disk emission and tentatively rule out dense molecular gas as well as optically thin atomic or ionized gas as its possible origin. We propose instead that the inner emission traces the presence of very refractory grains in a partially cleared region, extending at least to 0.5 AU. If so, we may be observing the disk of HD163296 just before it reaches the transition disk phase. However, we note that the nature of the refractory grains or even the possibility for any grain to survive at the very high temperatures we require (~2100-2300 K at 0.1 AU from the star) is unclear and should be investigated further., 14 pages; 12 figures; accepted by A&A

Published
2010
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13. An integrated optics beam combiner for the second generation VLTI instruments

Author

M. Benisty, J.-P. Berger, L. Jocou, P. Labeye, F. Malbet, K. Perraut, P. Kern, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Computer science, Aperture synthesis, FOS: Physical sciences, 01 natural sciences, law.invention, 010309 optics, Optics, Optical path, law, K band, 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Very Large Telescope, business.industry, Near-infrared spectroscopy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, H band, Polarization (waves), Wavelength, Interferometry, Space and Planetary Science, Achromatic lens, business, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The very recent years have seen a promising start in scientific publications making use of images produced by near-infrared long-baseline interferometry. The technique has reached, at last, a technical maturity level that opens new avenues for numerous astrophysical topics requiring milli-arcsecond model-independent imaging. The Very Large Telescope Interferometer (VLTI) is on the path to be equipped with instruments capable to combine between four to six telescopes. In the framework of the VLTI second generation instruments Gravity and VSI, we propose a new beam combining concept using Integrated Optics (IO) technologies with a novel ABCD-like fringe encoding scheme. Our goal is to demonstrate that IO-based combination brings considerable advantages in terms of instrumental design and performance. We therefore aim at giving a full characterization of an IO beam combiner to establish its performances and check its compliance with the specifications of an imaging instrument. Laboratory measurements were made in the H band with a dedicated testbed. We studied the beam combiners through the analysis of throughput, instrumental visibilities, phases and closure phases in wide band as well as with spectral dispersion. Study of the polarization properties is also done. We obtain competitive throughput, high and stable instrumental contrasts, stable but non-zero closure phases which we attribute to internal well calibrable optical path differences. We validate a new static and achromatic phase shifting IO function close to the nominal 90deg value. All these observables show limited chromaticity over the H band range. Our results demonstrate that such ABCD-like beam combiners are particularly well suited to achieve aperture synthesis imaging. This opens the way to extend to all near infrared wavelengths and in particular, the K band., 13 pages, 11 figures, 13 tables; Accepted by A&A

Published
2009
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14. GRAVITY: Astrometry on the galactic center and beyond

Author

Xavier Haubois, Vianak Naranjo, J. Ziegleder, P. Fédou, António Amorim, Jose Ramos, S. Lacour, Fabien Malbet, Nico Hamaus, L. Jocou, Stefan Hippler, Eric Gendron, A. Böhm, Werner Laun, M. Thiel, Oliver Pfuhl, Stefan Gillessen, Sebastian Rabien, Guy Perrin, Daniel Rouan, Harald Baumeister, Katie Dodds-Eden, K. Houairi, Christian Straubmeier, Th. Henning, Markus Schöller, Rainer Lenzen, Jorge Lima, A. Gräter, J. Kolmeder, Udo Neumann, Reinhard Genzel, Gérard Rousset, Thibaut Paumard, Pierre Kervella, J.-P. Berger, Andrea Richichi, Reiner Hofmann, Frédéric Cassaing, R.-R. Rohloff, Andreas Eckart, Marcus Haug, Ralf Klein, Felix Hormuth, K. Perraut, H. Bartko, Frank Eisenhauer, Wolfgang Brandner, Yann Clénet, S. Kellner, 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), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Ingénieurs, Techniciens et Administratifs, Groupement d'Intérêt Scientifique du Partenariat Haute résolution Angulaire Sol-Espace (GIS PHASE ), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Max-Planck-Institut für Astronomie (MPIA), Physikalisches Institut, Universität zu Köln, European Southern Observatory (ESO), Max-Planck-Institut für Extraterrestriche Physik (MPE), 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), ONERA, and SIM/IDL, Faculdade de Ciências da Universidade de Lisboa

Subjects
Wavefront, Physics, Event horizon, Milky Way, Galactic Center, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Field of view, Astrometry, Black hole, Space and Planetary Science, Adaptive optics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract

International audience; We present the second-generation VLTI instrument GRAVITY, which currently is in the preliminary design phase. GRAVITY is specifically designed to observe highly relativistic motions of matter close to the event horizon of Sgr A*, the massive black hole at the center of the Milky Way. We have identified the key design features needed to achieve this goal and present the resulting instrument concept. It includes an integrated optics, four-telescope, dual feed beam combiner operated in a cryogenic vessel, near-infrared wavefront sensing adaptive optics, fringe tracking on secondary sources within the field of view of the VLTI and a novel metrology concept. Simulations show that the planned design matches the scientific needs; in particular that 10 muas astrometry is feasible for a source with a magnitude of mK = 15 like Sgr A*, given the availability of suitable phase reference sources.

Published
2009
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15. Milli-arcsecond Astrophysics with VSI, the VLTI Spectro-imager in the ELT Era

Author

F. Malbet, D. Buscher, G. Weigelt, P. Garcia, M. Gai, D. Lorenzetti, J. Surdej, J. Hron, R. Neuhäuser, P. Kern, L. Jocou, J.-P. Berger, O. Absil, U. Beckmann, L. Corcione, G. Duvert, M. Filho, P. Labeye, E. Le Coarer, G. Li Causi, J. Lima, K. Perraut, E. Tatulli, E. Thiébaut, J. Young, G. Zins, A. Amorim, B. Aringer, T. Beckert, M. Benisty, X. Bonfils, A. Chelli, O. Chesneau, A. Chiavassa, R. Corradi, M. de Becker, A. Delboulbé, G. Duchêne, T. Forveille, C. Haniff, E. Herwats, K.-H. Hofmann, J.-B. Le Bouquin, S. Ligori, D. Loreggia, A. Marconi, A. Moitinho, B. Nisini, P.-O. Petrucci, J. Rebordao, R. Speziali, L. Testi, F. Vitali, 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), Cavendish Laboratory, University of Cambridge [UK] (CAM), Max-Planck-Institut für Radioastronomie (MPIFR), Laboratoire de Modélisation Multi-échelles des Combustibles (LM2C), Service d'Etudes de Simulation du Comportement du combustibles (SESC), Département d'Etudes des Combustibles (DEC), CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Département d'Etudes des Combustibles (DEC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Osservatorio di Astrofisica di Roma (OAR), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Institut für Astrophysik [Wien], Universität Wien, Astrophysical Institute and University Observatory [Jena] (AIU), Friedrich-Schiller-Universität Jena, Institut d'Electronique du Solide et des Systèmes (InESS), Centre National de la Recherche Scientifique (CNRS), Centre d'Études Préhistoire, Antiquité, Moyen-Age (CEPAM), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto [Porto], Laboratoire d'Electronique et des Technologies de l'Information (CEA-LETI), Université Grenoble Alpes (UGA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), INAF - Osservatorio Astronomico di Roma (OAR), SIM/IDL Faculdade de Ciências da Universidade de Lisboa (FCUL), University of Lisboa, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS 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), Institut für Astronomie, Universität Wien (IFA), Laboratoire Gemini (LG), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Groupe de Recherche en Astronomie et Astrophysique du Languedoc (GRAAL), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Canarias (IAC), Département Recherches Subatomiques (DRS-IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Instituto Nacional de Engenharia, Tecnologia e Inovacco (INETI), European Southern Observatory (ESO), Department of Computer Science and Engineering [Bologna] (DISI), Università di Bologna [Bologna] (UNIBO), A. Moorwood, VSI collaboration, CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Universidade do Porto, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Engenharia, Tecnologia e Inovacao (INETI), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Universidade do Porto = University of Porto, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and 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)

Subjects
Physics, Active galactic nucleus, Mode (statistics), Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Domain (software engineering), [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Stars, Interferometry, Wavelength, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

8 pages. To be published in the proceedings of the ESO workshop "Science with the VLT in the ELT Era", held in Garching (Germany) on 8-12 October 2007, A. Moorwood editor.; Nowadays, compact sources relatively warm like surfaces of nearby stars, circumstellar environments of stars from early stages to the most evolved ones and surroundings of active galactic nuclei can be investigated at milli-arcsecond scales only with the VLT in its interferometric mode. We propose a spectro-imager, named VSI (VLTI spectro-imager), which is capable to probe these sources both over spatial and spectral scales in the near-infrared domain. This instrument will provide information complementary to what is obtained at the same time with ALMA at different wavelengths and the extreme large telescopes.

Published
2009
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16. PEGASE, an infrared interferometer to study stellar environments and low mass companions around nearby stars

Author

M. Ollivier, O. Absil, F. Allard, J.-P. Berger, P. Bordé, F. Cassaing, B. Chazelas, A. Chelli, O. Chesneau, V. Coudé du Foresto, D. Defrère, P. Duchon, P. Gabor, J. Gay, E. Herwats, S. Jacquinod, P. Kern, P. Kervella, J.-M. Le Duigou, A. Léger, B. Lopez, F. Malbet, D. Mourard, D. Pelat, G. Perrin, Y. Rabbia, D. Rouan, J.-M. Reiss, G. Rousset, F. Selsis, P. Stee, J. Surdej, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), Laboratoire d'Étude des Phénomènes de Transfert et de l'Instantanéité : Agro-industrie et Bâtiment (LEPTIAB), Université de La Rochelle (ULR), 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), ONERA - The French Aerospace Lab [Châtillon], ONERA-Université Paris Saclay (COmUE), Laboratoire Hippolyte Fizeau (FIZEAU), 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), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB), Laboratoire Gemini (LG), 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), Laboratoire d'étude des Mécanismes de la recombinaison (LMR), Centre National de la Recherche Scientifique (CNRS), Departement d'Astrophysique Extragalactique et de Cosmologie (DAEC), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), 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), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), La Rochelle Université (ULR), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS), 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), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Cosmic Vision, Infrared, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 7. Clean energy, 010309 optics, 0103 physical sciences, 010303 astronomy & astrophysics, Low mass objects, Astrophysics::Galaxy Astrophysics, Physics, Spacecraft, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Interferometry, Stars, Space interferometry, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Darwin (spacecraft), Astrophysics::Earth and Planetary Astrophysics, Nulling interferometry, business, Low Mass, Circumstellar habitable zone
Abstract

International audience; PEGASE is a mission dedicated to the exploration of the environment (including habitable zone) of young and solar-type stars (particularly those in the DARWIN catalogue) and the observation of low mass companions around nearby stars. It is a space interferometer project composed of three free flying spacecraft, respectively featuring two 40 cm siderostats and a beam combiner working in the visible and near infrared. It has been proposed to ESA as an answer to the first “Cosmic Vision” call for proposals, as an M mission. The concept also enables full-scale demonstration of space nulling interferometry operation for DARWIN.

Published
2009
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17. Combining and cophasing a telescope array in a single chip-integrated optics: a new solution for spaced based aperture synthesis interferometry

Author

Karine Perraut, P. Haguenauer, P. Kern, I. Schanen, Etienne LeCoarer, Jean-Emmanuel Broquin, M. Lacolle, Fabien Malbet, J. P. Berger, Pierre Benech, Sylvain Blaize, E. Ghibaudo, C. Sanchez-Perez, G. Fontaine, 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 Microélectronique, Electromagnétisme et Photonique (IMEP), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Nanotechnologie et d'Instrumentation Optique (LNIO), Institut Charles Delaunay (ICD), Université de Technologie de Troyes (UTT)-Centre National de la Recherche Scientifique (CNRS)-Université de Technologie de Troyes (UTT)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF), and Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Active galactic nucleus, Aperture synthesis, Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, law.invention, Telescope, Optics, interferometers, law, Astronomical interferometer, Astrophysics::Solar and Stellar Astrophysics, Angular resolution, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, telescopes, waveguides, Exoplanet, Cophasing, Interferometry, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Astrophysics::Earth and Planetary Astrophysics, business
Abstract

Astrophysical key programs such as exoplanet detection, young stars accretion disk and active galactic nuclei imaging require high angular resolution capability. Today, optical long baseline interferometers are the only instruments to allow such resolutions.

Published
2000
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19. Submilliarcsecond Optical Interferometry of the High-mass X-Ray Binary BP Cru with VLTI/GRAVITY.

Author

I. Waisberg, J. Dexter, O. Pfuhl, R. Abuter, A. Amorim, N. Anugu, J. P. Berger, N. Blind, H. Bonnet, W. Brandner, A. Buron, Y. Clénet, W. de Wit, C. Deen, F. Delplancke-Ströbele, R. Dembet, G. Duvert, A. Eckart, F. Eisenhauer, and P. Fédou

Subjects
CIRCUMSTELLAR matter, HIGH resolution imaging, INTERFEROMETRY, X-ray binaries, LOW mass stars, HIGH mass stars, VERY large telescope interferometer (Chile)
Abstract

We observe the high-mass X-ray binary (HMXB) BP Cru using interferometry in the near-infrared K band with VLTI/GRAVITY. Continuum visibilities are at most partially resolved, consistent with the predicted size of the hypergiant. Differential visibility amplitude () and phase () signatures are observed across the He i and Brγ lines, the latter seen strongly in emission, unusual for the donor star’s spectral type. For a baseline m, the differential phase rms corresponds to an astrometric precision of . We generalize expressions for image centroid displacements and variances in the marginally resolved limit of interferometry to spectrally resolved data, and use them to derive model-independent properties of the emission such as its asymmetry, extension, and strong wavelength dependence. We propose geometric models based on an extended and distorted wind and/or a high-density gas stream, which has long been predicted to be present in this system. The observations show that optical interferometry is now able to resolve HMXBs at the spatial scale where accretion takes place, and therefore to probe the effects of the gravitational and radiation fields of the compact object on its environment. [ABSTRACT FROM AUTHOR]

Published
2017
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