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4 results on '"Mathias Nowak"'

1. K-Stacker: an algorithm to hack the orbital parameters of planets hidden in high-contrast imaging: First applications to VLT/SPHERE multi-epoch observations

Author

Jean-Luc Beuzit, Arthur Vigan, Markus Feldt, Kjetil Dohlen, H. Le Coroller, E. Sissa, A. L. Maire, Pierre Vernazza, A. Schneeberger, Anthony Cheetham, S. Rochat, Michael R. Meyer, Thierry Fusco, Mariangela Bonavita, D. Estevez, D. Le Mignant, François Ménard, Joany Andreina Manjarres Ramos, Matthias Samland, Mathias Nowak, Mickael Bonnefoy, J. C. Lambert, Alice Zurlo, Valentina D'Orazi, Dino Mesa, Philippe Delorme, A. Boccaletti, Hervé Beust, R. Galicher, Roxanne Ligi, Gael Chauvin, A-M. Lagrange, Markus Janson, T. Fenouillet, Raffaele Gratton, David Mouillet, L. Arnold, M. Devinat, Silvano Desidera, Maud Langlois, J. Bec-Canet, C. Desgrange, Jean-François Sauvage, Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de 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), European Southern Observatory (ESO), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), 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'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), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Department of Astronomy, Stockholm University, Department of Biochemistry and Molecular Biology, Mayo Clinic, DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, University of Copenhagen = Københavns Universitet (KU), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), 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, 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), Université de Genève = University of Geneva (UNIGE), and University of Copenhagen = Københavns Universitet (UCPH)

Subjects
[PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], planets and satellites: dynamical evolution and stability, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Context (language use), Astrophysics, instrumentation: adaptive optics, 01 natural sciences, stars: individual: HD 95086, 03 medical and health sciences, Planet, instrumentation: high angular resolution, 0103 physical sciences, Gemini Planet Imager, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), 030304 developmental biology, Orbital elements, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 0303 health sciences, stars: individual: β Pictoris, Astronomy and Astrophysics, Astrometry, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], methods: data analysis, Exoplanet, Radial velocity, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Orbital motion, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Algorithm, Astrophysics - Earth and Planetary Astrophysics
Abstract

Recent high-contrast imaging surveys, looking for planets in young, nearby systems showed evidence of a small number of giant planets at relatively large separation beyond typically 20 au where those surveys are the most sensitive. Access to smaller physical separations between 5 and 20 au is the next step for future planet imagers on 10 m telescopes and ELTs in order to bridge the gap with indirect techniques (radial velocity, transit, astrometry with Gaia). In that context, we recently proposed a new algorithm, Keplerian-Stacker, combining multiple observations acquired at different epochs and taking into account the orbital motion of a potential planet present in the images to boost the ultimate detection limit. We showed that this algorithm is able to find planets in time series of simulated images of SPHERE even when a planet remains undetected at one epoch. Here, we validate the K-Stacker algorithm performances on real SPHERE datasets, to demonstrate its resilience to instrumental speckles and the gain offered in terms of true detection. This will motivate future dedicated multi-epoch observation campaigns in high-contrast imaging to search for planets in emitted and reflected light. Results. We show that K-Stacker achieves high success rate when the SNR of the planet in the stacked image reaches 7. The improvement of the SNR ratio goes as the square root of the total exposure time. During the blind test and the redetection of HD 95086 b, and betaPic b, we highlight the ability of K-Stacker to find orbital solutions consistent with the ones derived by the state of the art MCMC orbital fitting techniques, confirming that in addition to the detection gain, K-Stacker offers the opportunity to characterize the most probable orbital solutions of the exoplanets recovered at low signal to noise., Comment: Astronomy & Astrophysics accepted, 13 Pages, 11 Figures

Published
2020
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2. Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e

Author

Frank Eisenhauer, Th. Henning, P. Mollière, Jingxiu Wang, E. F. van Dishoeck, T. Molyarova, Jinyi Shangguan, Pierre Kervella, Tomas Stolker, Alexandra Z. Greenbaum, Mathias Nowak, Sylvestre Lacour, Alice Zurlo, E. Nasedkin, Gabriel-Dominique Marleau, Gilles Otten, D. Semenov, Anne-Lise Maire, Ignas Snellen, Laurent Pueyo, Sasha Hinkley, Arthur Vigan, Laura Kreidberg, Benjamin Charnay, Paulo J. V. Garcia, Julien Girard, P. T. de Zeeuw, R. Garcia Lopez, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, European Southern Observatory (ESO), 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)

Subjects
010504 meteorology & atmospheric sciences, Opacity, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Spectral line, methods: numerical, Atmosphere, Planet, 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, instrumentation: spectrographs, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: atmospheres, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Scattering, Astronomy and Astrophysics, Exoplanet, radiative transfer, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Clouds are ubiquitous in exoplanet atmospheres and represent a challenge for the model interpretation of their spectra. Complex cloud models are too numerically costly for generating a large number of spectra, while more efficient models may be too strongly simplified. We aim to constrain the atmospheric properties of the directly imaged planet HR 8799e with a free retrieval approach. We use our radiative transfer code petitRADTRANS for generating spectra, which we couple to the PyMultiNest tool. We added the effect of multiple scattering which is important for treating clouds. Two cloud model parameterizations are tested: the first incorporates the mixing and settling of condensates, the second simply parameterizes the functional form of the opacity. In mock retrievals, using an inadequate cloud model may result in atmospheres that are more isothermal and less cloudy than the input. Applying our framework on observations of HR 8799e made with the GPI, SPHERE and GRAVITY, we find a cloudy atmosphere governed by disequilibrium chemistry, confirming previous analyses. We retrieve that ${\rm C/O}=0.60_{-0.08}^{+0.07}$. Other models have not yet produced a well constrained C/O value for this planet. The retrieved C/O values of both cloud models are consistent, while leading to different atmospheric structures: cloudy, or more isothermal and less cloudy. Fitting the observations with the self-consistent Exo-REM model leads to comparable results, while not constraining C/O. With data from the most sensitive instruments, retrieval analyses of directly imaged planets are possible. The inferred C/O ratio of HR 8799e is independent of the cloud model and thus appears to be a robust. This C/O is consistent with stellar, which could indicate that the HR 8799e formed outside the CO$_2$ or CO iceline. As it is the innermost planet of the system, this constraint could apply to all HR 8799 planets., Comment: Accepted for publication in A&A, 28 pages, 13 figures, updated author list

Published
2020
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3. Short life and abrupt death of PicSat, a small 3U CubeSat dreaming of exoplanet detection

Author

Guillaume Schworer, Mathias Nowak, Antoine Crouzier, Lester David, Vincent Lapeyrere, and Sylvestre Lacour

Subjects
010504 meteorology & atmospheric sciences, Payload, Computer science, FOS: Physical sciences, Astronomy, 01 natural sciences, Exoplanet, Starlight, 0103 physical sciences, Hill sphere, Beta Pictoris, Satellite, CubeSat, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Transit (satellite), 0105 earth and related environmental sciences
Abstract

PicSat was a three unit CubeSat (measuring 30 cm x 10 cm x 10 cm) which was developed to monitor the beta Pictoris system. The main science objective was the detection of a possible transit of the giant planet beta Pictoris b's Hill sphere. Secondary objectives included studying the circumstellar disk, and detecting exocomets in the visible band. The mission also had a technical objective: demonstrate our ability to inject starlight in a single mode fiber, on a small satellite platform. To answer all those objectives, a dedicated opto-mechanical payload was built, and integrated in a commercial 3U platform, along with a commercial ADCS (Attitude Determination and Control System). The satellite successfully reached Low Earth Orbit on the PSLV-C40 rocket, on January, 12, 2018. Unfortunately, on March, 20, 2018, after 10 weeks of operations, the satellite fell silent, and the mission came to an early end. Furthermore, due to a failure of the ADCS, the satellite never actually pointed toward its target star during the 10 weeks of operations. In this paper, we report on the PicSat mission development process, and on the reasons why it did not deliver any useful astronomical data., Comment: 11 pages, 11 figures

Published
2018
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4. A space interferometer on a 6U Cubesat: FIRST-S (Conference Presentation)

Author

Sylvestre Lacour, Vincent Lapeyrere, Mathias Nowak, Antoine Crouzier, Mathurin Grenot, and Lester David

Subjects
Physics, business.industry, Aperture, Context (language use), Active optics, Exoplanet, law.invention, Telescope, Interferometry, Optics, law, CubeSat, Photonics, business
Abstract

The FIRST-S project is an astronomical project in the context of exoplanet detection. The scientific objective of this mission would be to study the visible emission of exozodiacal light in the habitable zone around the closest stars. It requires high dynamic range (103) at moderate resolution (arcsec). The proposed instrument is 60 cm baseline stellar interferometer with nulling capabilities based on single-mode fibers and LiNbO3 (Lithium niobate) photonic ship on a 6U CubeSat. This nulling technique is currently developed in the context of FIRST project (Fibered Imager foR a Single Telescope), and is suitable for a nanosatellite application. The first part of this challenge – controlling the injection of the star light in a single-mode fiber with a accuracy of 1 arcsecond – is addressed by the PicSat mission. PicSat is using a 2 stages pointing system: the Attitude Determination and Control System (ADCS) of the platform, and the control of a 2 axis piezo stage. The design is based on two 9cm aperture telescope, inspired by the PicSat payload. The light collected by these two telescopes is guided with the single mode fibers to the integrated active optics. The active part of this ship controls the optical phase difference to a nanometer accuracy over few microns and allow to scan the null fringe. The interferometer itself is used as an OPD sensor and interacts with the ADCS of the platform to maintain this OPD lower to few microns. In this presentation I will present the performances of PicSat on which be can base this design. The satellite design will then be described including the telescopes and injection into fibers and the recombination system. Finally the first results on a lab demonstrator with these parts will be shown.

Published
2018
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