Optical interferometers can now routinely produce images of stellar surfaces, witness exoplanets in orbit and probe the structures of active galactic nuclei. Widespread scientific relevance to a broad cross-section of the astronomical community has long been hampered by the issue of sensitivity, which has seen tremendous progress in the past years. For the last few decades, topically focused SPIE meetings have continued to play a unique role in fostering our field: this is the singular venue that brings together interferometrists from the world over.

Our previous meeting (held Online in Dec 2020) showed very exciting progress in overcoming some of the most firmly entrenched obstacles that have long plagued the field, as well as outstanding results, in particular on the Galactic Center (which undoubtedly contributed to the Nobel prize in Physics to be co-attributed to R. Genzel in 2020), as well as exoplanets astrometry and spectra beyond what any other technique can offer at the moment. Progress on several fronts, such as the roll-out of active/adaptive wavefront correction, as well as dramatic enhancements in low-noise detector technologies, now promises to finally unleash “stellar interferometry” from its traditional niche within stellar physics, perhaps calling for our community to rethink its identity as working in “astrophysical interferometry." The wealth of exciting results from the past two years gives testimony to these ongoing rapid developments.

The primary goals of this conference are to allow the attendees to learn firsthand about the exciting capabilities found in facilities across the globe and to discuss the future prospects for interferometry in technology and instrumentation. Its primary focus will be on the latest innovations in technology and engineering for ground- and space-based interferometry in the optical and infrared, including new instrumentation, techniques and software. Scientific results will be highlighted, with priority given to findings that push current facilities to their limits and/or exploit innovative techniques and technologies. Results should particularly serve to illustrate novel observations or analytical techniques.

Invited talks and panel discussions will feature in the program, however most time will be competitively allocated based on the response to this Call for Papers. We solicit contributed papers on these and related topics: We expect a large number of submitted abstracts and the program committee will actively assign contributed papers to be either oral or poster, unless the author requests poster presentation. Students who received or expect to receive their Ph.D.s after January 1, 2021, should include the word “THESIS” in their abstract titles to be eligible for the “Best Dissertation” prize to be awarded during the conference.

All presenters will be asked to provide a manuscript in advance of the meeting for publication in a proceedings volume to be published on the SPIE Digital Library soon after the conference. ;
In progress – view active session
Conference 12183

Optical and Infrared Interferometry and Imaging VIII

17 - 22 July 2022 | Room 520 b
View Session ∨
  • 1: Current and Planned Facilities and Instruments I
  • 2: Current and Planned Facilities and Instruments II
  • 3: Critical Subsystems I
  • 4: Critical Subsystems II
  • 5: Observing Techniques I
  • 6: Observing Techniques II
  • 7: Technologies
  • 8: Space Interferometry Technology
  • 9: Data Processing Analysis Access and Discovery
  • 10: Future of Interferometry
  • Posters - Critical Subsystems
  • Posters - Observing Techniques
  • Posters - Technologies
  • Posters - Data Processing Analysis Access and Discovery
  • Posters - Future of Interferometry
Information

SCHEDULE AND POST-DEADLINE ABSTRACT SUBMISSIONS

  • Conferences schedules are currently being finalized (more information available by mid-May.)
  • Submissions accepted through 22 May 2022

Session 1: Current and Planned Facilities and Instruments I
18 July 2022 • 10:30 - 13:00 | Room 520 b
Session Chair: Antoine Mérand, European Southern Observatory (Germany)
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Author(s): Steve Ertel, The Univ. of Arizona (United States)
18 July 2022 • 10:30 - 11:00 | Room 520 b
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The LBT Interferometer (LBTI) is a NASA-funded strategic (PI) instrument on the Large Binocular Telescope (LBT). It is designed for exceptional angular resolution and sensitivity at thermal-infrared wavelengths for both direct adaptive optics imaging and interferometry. Interferometric modes combine the two 8.4m apertures of the LBT for nulling interferometry, Fizeau imaging interferometry, and non-redundant aperture masking with baselines up to 23m. LBT/LBTI features many of the characteristics of future 30m-class telescopes making it an important ELT instrumentation and science pathfinder. At the same time, the LBTI has successfully struck a balance between an active instrumentation experiment, its core NASA mission, and a productive, general community science instrument. I will present an overview and status update of the LBTI, as well as ongoing projects and future perspectives. Key talking points will be illustrated using recent science results.
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Author(s): Douglas R. Gies, Theo A. ten Brummelaar, Gail Schaefer, Georgia State Univ. (United States)
18 July 2022 • 11:00 - 11:30 | Room 520 b
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The Center for High Angular Resolution Astronomy Array is a six-element interferometer with baselines ranging from 31 to 331 m. Three new beam combiners are being added: MYSTIC is a 6-telescope combiner for K-band, SPICA is a 6-telescope combiner for the optical R-band, and SILMARIL is a 3-telescope combiner for high sensitivity in H- and K-bands. A seventh, portable telescope will use fiber optics for beam transport and will increase the baselines to 1 km. Observing time is available through a program funded by NSF. The programs are solicited and peer-reviewed by NSF's National Optical-Infrared Astronomy Research Laboratory.
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Author(s): Gerard T. van Belle, Lowell Observatory (United States); James H. Clark, Henrique R. Schmitt, U.S. Naval Research Lab. (United States); David Noble, Lowell Observatory (United States); Anders M. Jorgensen, New Mexico Institute of Mining and Technology (United States); David Mozurkewich, Seabrook Engineering (United States); J. Thomas Armstrong, Ellyn K. Baines, Merrick DeWitt, Peter Kurtz, Ty Martinez, Jordan Stone, Sergio R. Restaino, U.S. Naval Research Lab. (United States); Thomas Coleman, Wyatt E. Clark, Ben Hardesty, Khristian Jones, Bradley Kingsley, Lowell Observatory (United States); Nicholas Green, ATA Corp. (United States)
18 July 2022 • 11:30 - 12:00 | Room 520 b
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We have been progressing on our comprehensive program of improving high-resolution imaging at the Navy Precision Optical Interferometer (NPOI) hosted at Lowell Observatory's Anderson Mesa site, for the purpose of spatially resolved observations of faint objects at scales down to less than 1 milliarcsecond. This program includes the 3 x 1 meter telescope upgrade for improved sensitivity, and the 'Plus-Up' activities aimed at facility modernization and upgrades.
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Author(s): Michelle J. Creech-Eakman, Magdalena Ridge Observatory, New Mexico Institute of Mining and Technology (United States); Van D. Romero, New Mexico Institute of Mining and Technology (United States); Christopher A. Haniff, David F. Buscher, John S. Young, Univ. of Cambridge (United Kingdom); Christopher Salcido, Magdalena Ridge Observatory, New Mexico Institute of Mining and Technology (United States)
18 July 2022 • 12:00 - 12:30 | Room 520 b
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The Magdalena Ridge Observatory Interferometer has been conceived to be the most ambitious optical/near-infrared long-baseline imaging interferometer in the world today. We anticipate receiving the second telescope mount and enclosure and associated beamline infrastructure to enable us to attempt first fringes measurements late in 2022 or early in 2023. Having reached this important milestone, we anticipate receiving the third copy of all beamline components about one year later and attempting closure phase measurements. We will present a status update and plans under the new Cooperative Agreement with AFRL for the next phases of the project.
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VLTI Status update (Invited Paper)
Author(s): Antoine Mérand, Roberto Abuter, European Southern Observatory (Germany); Juan Pablo Araneda, Pierre Bourget, European Southern Observatory (Chile); Paul Bristow, European Southern Observatory (Germany); Pablo Burgos, European Southern Observatory (Chile); Françoise Delplancke-Ströbele, Roderick Dembet, European Southern Observatory (Germany); Juan Pablo Gil, European Southern Observatory (Chile); Andreas Glindemann, Frédéric Gonté, European Southern Observatory (Germany); Patricia Guajardo, Xavier Haubois, European Southern Observatory (Chile); Norbert Hubin, Christian Hummel, European Southern Observatory (Germany); Heidi H. Korhonen, Aaron Labdon, European Southern Observatory (Chile); Sylvestre Lacour, European Southern Observatory (Germany), Observatoire de Paris, CNRS (France); Sylvain Oberti, European Southern Observatory (Germany); Claudia Paladini, Laurent Pallanca, European Southern Observatory (Chile); Luca Pasquini, Isabelle Percheron, European Southern Observatory (Germany); Miguel Riquelme, Thomas Rivinius, Peter Scicluna, European Southern Observatory (Chile); Markus Schoeller, European Southern Observatory (Germany); Nicolas Schuhler, Konrad R. W. Tristram, European Southern Observatory (Chile); Markus Wittkowski, Julien Woillez, European Southern Observatory (Germany); Gérard Zins, European Southern Observatory (Germany), European Southern Observatory (Chile)
18 July 2022 • 12:30 - 13:00 | Room 520 b
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I will present the recent updates of VLTI regarding operations, performances and new system.
Session 2: Current and Planned Facilities and Instruments II
18 July 2022 • 14:00 - 18:00
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Author(s): Frank Eisenhauer, GRAVITY+ Collaboration, Max-Planck-Institut für extraterrestrische Physik (Germany)
18 July 2022 • 14:00 - 14:30
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GRAVITY and the VLTI have transformed high angular resolution astronomy, now routinely offering milli-arcsecond resolution imaging, a sensitivity increase by factor thousands over previous interferometers, 30-100 micro-arcsecond astrometry, and micro-arcsecond differential spectro-astrometry. Our presentation takes us from exoplanets all the way to distant quasars, with special focus on the Galactic Center. The GRAVITY+ project will soon boost interferometry to the next level, opening up the extragalactic sky, and providing ever higher contrast for observations of exoplanets. This is made possible with wide-field fringe-tracking, laser guide star adaptive optics, and performance improvements of GRAVITY and the VLTI. We discuss the discovery space opening up with GRAVITY+, e.g. the detailed view on AGN at cosmic dawn, the detection and characterization of exoplanets and their atmospheres, the spin of the Galactic Center black hole, and microlenses tracing the Milky Ways dark components.
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Author(s): Denis Mourard, Philippe Berio, Observatoire de la Côte d'Azur (France); Cyril Pannetier, Observatoire de la Côte d’Azur (France); Nicolas Nardetto, Observatoire de la Côte d'Azur (France); Simon Albrecht, Aarhus Univ. (Denmark); Fatmé Allouche, Observatoire de la Côte d’Azur (France); Christophe Bailet, Observatoire de la Côte d'Azur (France); Laurent Bourgès, Institut de Planétologie et d’Astrophysique de Grenoble, Univ. Grenoble Alpes (France); Theo A. ten Brummelaar, CHARA Array, Georgia State Univ. (United States); Orlagh Creevey, Observatoire de la Côte d'Azur (France); Sebastien Deheuvels, Institut de Recherche en Astrophysique et Planétologie (France); Julien Dejonghe, Armando Domiciano, Pierre Geneslay, Observatoire de la Côte d'Azur (France); Douglas R. Gies, CHARA Array, Georgia State Univ. (United States); Estelle Jacqmart, Stéphane Lagarde, Daniel Lecron, Roxanne Ligi, Observatoire de la Côte d'Azur (France); Guillaume Mella, Institut de Planétologie et d’Astrophysique de Grenoble, Univ. Grenoble Alpes (France); Frédéric Morand, Sylvain Rousseau, David Salabert, Observatoire de la Côte d'Azur (France); Gail Schaefer, CHARA Array, Georgia State Univ. (United States); Alain Spang, Observatoire de la Côte d’Azur (France); Markus Wittkowski, European Southern Observatory (Germany)
18 July 2022 • 14:30 - 14:50
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With a possible angular resolution down to 0.1-0.2 mas using the 330m baselines and the access to the 600nm wavelength, the CHARA Array is ideally configured for addressing the question of the fundamental parameters of stars. CHARA/SPICA (Stellar Parameters and Images with a Cophased Array) aims at performing a large survey of stars all over the HR diagram with a particular focus on dwarfs. We will also pay a particular attention to the effects of the different kinds of variability (multiplicity, limb-darkening and other surface structure effects, winds and environment, rotation) on the reliability of the extracted fundamental parameters. SPICA is made of a visible 6T fibered instrument (SPICA-VIS) and of a near-infrared (H band) fringe sensor (SPICA-FT) installed in the MIRC-X instrument for fringe tracking. In this paper, we will detail the science program and the main characteristics of SPICA-VIS. We will also present the initial performance obtained during the Spring 2022.
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Author(s): Philippe Bério, Denis Mourard, Observatoire de la Côte d'Azur (France); Cyril Pannetier, Observatoire de la Côte d’Azur (France); Sylvain Rousseau, Observatoire de la Côte d'Azur (France); Fatmé Allouche, Observatoire de la Côte d’Azur (France); Julien Dejonghe, Daniel Lecron, Observatoire de la Côte d'Azur (France); John D. Monnier, Univ. of Michigan (United States); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Narsireddy Anugu, Theo A. ten Brummelaar, CHARA Array, Georgia State Univ. (United States); Frédéric Cassaing, ONERA (France)
18 July 2022 • 14:50 - 15:10
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SPICA-FT is part of the CHARA/SPICA instrument which combines a visible 6T fibered instrument (SPICA-VIS) with a H band 6T fringe sensor. SPICA-FT is a pairwise ABCD integrated optics combiner. The chip is installed in the MIRC-X instrument. The MIRC-X spectrograph could be fed either by the classical 6T fibered combiner or by the SPICA-FT integrated optics combiner. SPICA-FT also integrates dedicated fringe tracking software. We present the design of the integrated optics chip, its implementation in MIRC-X and the software architecture of the group-delay and phase-delay control loops. The final integrated optics chip and the software have been fully characterized in the laboratory. First on-sky tests of the integrated optics combiner were begun in 2020. We plan to continue the on-sky tests of the whole system (combiner + software) in Spring 2022. We present the main results, and we deduce the preliminary performance of SPICA-FT.
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Author(s): Bruno Lopez, Stéphane Lagarde, Observatoire de la Côte d'Azur (France); Romain G. Petrov, Observatoire de la Côte d’Azur (France); Walter Jaffe, Leiden Univ. (Netherlands); Fatmé Allouche, Observatoire de la Côte d’Azur (France); Julien Woillez, European Southern Observatory (Germany); Florentin Millour, James H. Leftley, Observatoire de la Côte d'Azur (France); Andreas Glindemann, Paul Bristow, Markus Schoeller, European Southern Observatory (Germany); Michael Lehmitz, Roy van Boekel, Max-Planck-Institut für Astronomie (Germany); Felix Bettonvil, ASTRON (Netherlands); Mathias Henninger, Gerd Weigelt, Max-Planck-Institut für Radioastronomie (Germany); Anthony Meilland, Alexis Matter, Sylvie Robbe-Dubois, Pierre Cruzalèbes, Observatoire de la Côte d'Azur (France); Eric Pantin, CEA-Paris-Saclay (France); Michiel Hogerheijde, Leiden Univ. (Netherlands); Jean-Charles Augereau, Observatoire des Sciences de l'Univers de Grenoble (France); Jozsef Varga, Leiden Univ. (Netherlands); William C. Danchi, NASA (United States); Claudia Paladini, European Southern Observatory (Germany); Thomas Henning, Max-Planck-Institut für Astronomie (Germany); Pierre Bourget, European Southern Observatory (Chile); Klaus Meisenheimer, Max-Planck-Institut für Astronomie (Germany); Gérard Zins, Isabelle Percheron, European Southern Observatory (Germany); Leonard Burtscher, Leiden Univ. (Netherlands); Laurens B. F. M. Waters, Radboud Univ. (Netherlands); Carsten Dominik, Univ. of Amsterdam (Netherlands); Christian Hummel, European Southern Observatory (Germany); Miguel Riquelme, European Southern Observatory (Chile); Werner Laun, Max-Planck-Institut für Astronomie (Germany); Eddy Elswijk, ASTRON (Netherlands)
18 July 2022 • 15:10 - 15:30
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We provide an overview of MATISSE at the VLTI near the end of its commissionning and after 3 semesters of first science observations. We summarize the key instrumental features and choices, its observing modes, global data reduction options, measurables and performances. MATISSE can be operated alone or with the GRAVITY fringe tracker in the so-called GRA4MAT mode. We present the updated MATISSE standalone performances and illustrate each critical measure as well as the very powerful multi band imaging capability, yielding thermal and dust composition maps, with a selection of frontline science results on AGNs, disks around YSOs and stellar physics. The improvement of performances with GRA4MAT as well as the specific issues related to fringe tracking in K for science observations in L, M and N such as the fringe jumps and the chromatic OPD will be tackled but would also be detailed in a complementary presentation.
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Author(s): Benjamin R. Setterholm, John D. Monnier, Univ. of Michigan (United States); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Narsireddy Anugu, CHARA Array, Georgia State Univ. (United States); Jacob Ennis, Univ. of Michigan (United States); Stefan Kraus, Univ. of Exeter (United Kingdom); Cyprien Lanthermann, Gail Schaefer, CHARA Array, Georgia State Univ. (United States); Laurent Jocou, Institut de Planétologie et d’Astrophysique de Grenoble (France); Theo A. ten Brummelaar, CHARA Array, Georgia State Univ. (United States)
18 July 2022 • 16:00 - 16:20
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We present the design and report the performance of the NSF funded, K-band interferometric beam combiner instrument MYSTIC (Michigan Young STar Imager at CHARA), installed in July 2021. Utilizing all baselines across CHARA’s 6 telescope array with a maximum angular resolution of 0.7 mas, we demonstrate fringe integration for targets as faint as 7.5 Kmag. MYSTIC operates in tandem with the CHARA workhorse J+H-band instrument MIRC-X (see presentation led by Narsireddy Anugu in these proceedings), and is automatically available for current and future observing programs.
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Author(s): Juan Cortina, Ctr. de Investigaciones Energéticas, Medioambientales y Tecnológicas (Spain); Victor Acciari, Institut de Física d'Altes Energies (Spain); Adrian Biland, ETH Zurich (Switzerland); Eduardo Colombo, Institut de Física d'Altes Energies (Spain); Carlos da Costa, Univ. Complutense de Madrid (Spain); Carlos Delgado, Carlos Díaz, Ctr. de Investigaciones Energéticas, Medioambientales y Tecnológicas (Spain); Michele Fiori, INAF (Italy); David Fink, Max-Planck-Institut für Physik (Germany); Tarek Hassan, Irene Jiménez-Martínez, Ctr. de Investigaciones Energéticas, Medioambientales y Tecnológicas (Spain); Etienne Lyard, Observatoire de Genève (Switzerland); Mosè Mariotti, Univ. degli Studi di Padova (Italy); Gustavo Martínez, Ctr. de Investigaciones Energéticas, Medioambientales y Tecnológicas (Spain); Razmik Mirzoyan, Max-Planck-Institut für Physik (Germany); Giampiero Naletto, INAF (Italy); Nicolas Produit, Observatoire de Genève (Switzerland); Miguel Polo, Ctr. de Investigaciones Energéticas, Medioambientales y Tecnológicas (Spain); Thomas Schweizer, Max-Planck-Institut für Physik (Germany); Roland Walter, Observatoire de Genève (Switzerland); Caroline W. Wunderlich, Istituto Nazionale di Fisica Nucleare (Italy); Luca Zampieri, INAF (Italy)
18 July 2022 • 16:20 - 16:40
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The two MAGIC 17 m Cherenkov Telescopes have been equipped to work also as an intensity interferometer. Operating with baselines between ~40 and 90 m the interferometer is able to measure stellar diameters of 0.5 - 1 mas in the visible/near UV range with a sensitivity roughly 10x better than that achieved with the Narrabri interferometer. Besides, active mirror control allows to split the mirrors into sub-mirrors, which allows to make simultaneous calibration measurements of the zero-baseline correlation or to collect 6 baselines below 17 m with almost arbitrary orientation, corresponding to angular scales of ~1 - 50 mas. In the next year we are planning tests with the nearby CTA LST-1 23 m telescope. All 3 telescope pairs will be correlated simultaneously. Adding LST-1 is expected to increase the sensitivity by at least 1m and significantly imimprove the coverage of the u-v plane. If successful, this setup is scalable enough to be implemented in the full CTA arrays.
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Author(s): David B. Kieda, The Univ. of Utah (United States)
18 July 2022 • 16:40 - 17:00
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The VERITAS Imaging Air Cherenkov Telescope array (IACT) was augmented in 2019 with high-speed focal plane electronics to create a new Stellar Intensity Interferometry (SII) observational capability (VERITAS-SII, or VSII). VSII operates during bright moon periods, providing high angular resolution observations ( < 1 mas) in the B photometric band using idle telescope time. VSII has already demonstrated the ability to measure the diameters of two B stars at 416 nm (Beta CMa and Epsilon Ori) with < 5% accuracy using relatively short (5 hours) exposures [Abeysekara et al., Nature Astronomy 2020]. The VSII instrumentation was recently improved to increase instrumental sensitivity and observational efficiency. This paper describes the upgraded VSII instrumentation and documents the ongoing improvements in VSII sensitivity. The report describes VSII’s plans to extend SII measurements to dimmer magnitude stars and increase angular diameter measurement resolution to better than 1%.
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Author(s): Kevin Barjot, Elsa Huby, Observatoire de Paris (France); Sébastien B. Vievard, National Astronomical Observatory of Japan (United States); Manon Lallement, Sylvestre Lacour, Observatoire de Paris (France); Guillermo Martin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Nick Cvetojevic, Observatoire de la Côte d'Azur (France); Vincent Deo, Olivier Guyon, Julien Lozi, National Astronomical Observatory of Japan (United States); Takayuki Kotani, Astrobiology Ctr., National Institute of Natural Sciences (Japan); Cédric Cassagnettes, Adrien Billat, Teem Photonics (France); Franck Marchis, SETI Institute (United States); Guy Perrin, Vincent Lapeyrère, Daniel Rouan, Observatoire de Paris (France)
18 July 2022 • 17:00 - 17:20
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FIRSTv2 (Fibered Imager foR a Single Telescope version 2) is the upgrade of a post-AO spectro-interferometer (FIRST) that enables high contrast imaging and spectroscopy at spatial scales below the diffraction limit of a single telescope. It aims at using a photonic chip beam combiner, allowing the measurement of the complex visibility for every baseline independently thus improving the dynamic range. I will report on the first on-sky results obtained with several prototype chips integrated at the Subaru Telescope on unresolved and binary stars, for the first time in the visible.
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Author(s): Luca Zampieri, INAF - Osservatorio Astronomico di Padova (Italy); Giovanni Bonanno, Pietro Bruno, INAF - Osservatorio Astrofisico di Catania (Italy); Carmelo Gargano, INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo (Italy); Luigi Lessio, INAF - Osservatorio Astronomico di Padova (Italy); Giampiero Naletto, Univ. degli Studi di Padova (Italy); Lorenzo Paoletti, INAF - Osservatorio Astronomico di Padova (Italy); Gabriele Rodeghiero, INAF - Osservatorio di Astrofisica e Scienza dello Spazio (Italy); Giuseppe Romeo, INAF - Osservatorio Astrofisico di Catania (Italy); Andrea Bulgarelli, Vito Conforti, INAF - Osservatorio di Astrofisica e Scienza dello Spazio (Italy); Michele Fiori, Univ. degli Studi di Padova (Italy); Stefano Gallozzi, INAF - Osservatorio Astronomico di Roma (Italy); Fulvio Gianotti, INAF - Osservatorio di Astrofisica e Scienza dello Spazio (Italy); Alessandro Grillo, INAF - Osservatorio Astrofisico di Catania (Italy); Marco Landoni, INAF - Osservatorio Astronomico di Brera (Italy); Saverio Lombardi, Fabrizio Lucarelli, INAF - Osservatorio Astronomico di Roma (Italy); Aldo Morselli, Istituto Nazionale di Fisica Nucleare (Italy); Giovanni Occhipinti, INAF - Osservatorio Astrofisico di Catania (Italy); Nicolò Parmiggiani, INAF - Osservatorio di Astrofisica e Scienza dello Spazio (Italy); Claudio Pernechele, INAF - Osservatorio Astronomico di Padova (Italy); Gonzalo Rodriguez Fernandez, Istituto Nazionale di Fisica Nucleare (Italy); Federico Russo, INAF - Osservatorio di Astrofisica e Scienza dello Spazio (Italy); Giorgia Sironi, INAF - Osservatorio Astronomico di Brera (Italy); Maria Cristina Timpanaro, Valentina Giordano, INAF - Osservatorio Astrofisico di Catania (Italy); Giovanni Pareschi, INAF - Osservatorio Astronomico di Brera (Italy); Salvatore Scuderi, INAF - Istituto di Astrofisica Spaziale e Fisica cosmica Milano (Italy); Gino Tosti, Univ. degli Studi di Perugia (Italy)
18 July 2022 • 17:20 - 17:40
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The ASTRI Mini-Array is an International collaboration led by the Italian National Institute for Astrophysics (INAF), that is constructing and operating nine telescopes to perform Cherenkov and optical stellar intensity interferometry (SII) observations. After providing an overview of the scientific context and motivations for performing SII science with the ASTRI Mini-Array telescopes, we present the baseline design for the ASTRI Stellar Intensity Interferometry Instrument (SI3), a fast single photon counting instrument that will be mounted on the ASTRI telescopes and dedicated to performing SII observations of bright stars.
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Author(s): Nolan K. Matthews, Guillaume Labeyrie, Univ. Côte d'Azur (France), Institut de Physique de Nice, CNRS (France); Mathilde Hugbart, Institut de Physique de Nice (France), Institut de Physique de Nice, CNRS (France); Robin Kaiser, Univ. Côte d'Azur (France), Institut de Physique de Nice, CNRS (France); Jean-Pierre Rivet, Univ. Côte d'Azur (France), Observatoire de la Côte d'Azur (France), CNRS (France); Olivier Lai, Univ. Côte d'Azur (France), Observatoire de la Côte d'Azur (France), CNRS (France); Farrokh Vakili, David Vernet, Julien Chabé, Clémont Courde, Univ. Côte d'Azur (France), Observatoire de la Côte d'Azur (France), CNRS (France); William Guerin, Univ. Côte d'Azur (France), Institut de Physique de Nice, CNRS (France)
18 July 2022 • 17:40 - 18:00
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We present the current status of the I2C stellar intensity interferometer used towards high angular resolution observations of stars in visible wavelengths. A first order tip-tilt adaptive optics unit was integrated into the optical system to provide stabilized light collection and allows the adaption of the system onto additional optical telescopes. Using this setup, sequential single telescope temporal intensity interferometry measurements were performed with one of the 1m diameter telescopes of the C2PU observatory, a portable 1m diameter telescope, and also the 1.5m telescope of the MéO observatory. Spectral characterization of the instrument was performed in the laboratory using a high resolution spectrograph and additionally, this setup was used for proof of concept measurements of a multi spectral channel intensity interferometry system. In this talk, we will present these recent developments, and the ongoing campaigns with arrays of small diameter optical telescopes.
Session 3: Critical Subsystems I
19 July 2022 • 10:30 - 12:10 | Room 520 b
Session Chair: Stephanie Sallum, Univ. of California, Irvine (United States)
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Author(s): Denis Defrère, KU Leuven (Belgium); Olivier Absil, Liège Univ. (Belgium); Jean-Philippe Berger, Univ. Grenoble Alpes (France); Azzurra Bigioli, KU Leuven (Belgium); Benjamin Courtney-Barrer, European Southern Observatory (Chile); Colin Dandumont, Liège Univ. (Belgium); Alexandre Emsenhuber, Ludwig-Maximilians-Univ. München (Germany); Steve Ertel, The Univ. of Arizona (United States); Jonathan Gagne, Univ. de Montréal (Canada); Germain Garreau, KU Leuven (Belgium); Adrian M. Glauser, ETH Zurich (Switzerland); Simon Gross, Macquarie Univ. (Australia); Michael J. Ireland, Harry-Dean Kenchington Goldsmith, The Australian National Univ. (Australia); Stefan Kraus, Univ. of Exeter (United Kingdom); Lucas Labadie, Univ. zu Köln (Germany); Victor Laborde, Liège Univ. (Belgium); Romain Laugier, KU Leuven (Belgium); Jarron Leisenring, The Univ. of Arizona (United States); Jérôme Loicq, Technische Univ. Delft (Netherlands); Guillermo Martin, Univ. Grenoble Alpes (France); Frantz Martinache, Observatoire de la Côte d'Azur (France); Marc-Antoine Martinod, KU Leuven (Belgium); Alexis Matter, Observatoire de la Côte d'Azur (France); Alexandra Mazzoli, Liège Univ. (Belgium); Bertrand Mennesson, Jet Propulsion Lab., NASA (United States); Salman Muhammad, Gert Raskin, Bart Vandenbussche, Simon Verlinden, KU Leuven (Belgium); Julien Woillez, European Southern Observatory (Germany)
19 July 2022 • 10:30 - 10:50 | Room 520 b
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Hi-5 is the L’-band (3.5-4.0 μm) high-contrast imager of Asgard, an instrument suite in preparation for the visitor focus of the VLTI. The system is optimized for high-contrast and high-sensitivity imaging within the diffraction limit of a single UT/AT telescope. It is designed as a double-Bracewell nulling instrument producing spectrally-dispersed (R=20, 400, or 2000) simultaneous nulling and photometric outputs for self-calibration purposes. In this paper, we present an update of the project and the expected performance based on full end-to-end simulations and the latest planet formation models.
12183-17
Author(s): Romain G. Petrov, James H. Leftley, Univ. Côte d'Azur (France); Abdelkarim Boskri, Oukaimeden Observatory, Univ. Cadi Ayyad (Morocco); Massinissa Hadjara, Chinese Academy of Science South America Ctr. for Astronomy (CASSACA) (Chile); Fatmé Allouche, Stéphane Lagarde, Bruno Lopez, Florentin Millour, Univ. Côte d'Azur (France); Xinyang Chen, Shanghai Astronomical Observatory (China); Yinlei Hao, Zhejiang Univ. (China); Jinhua He, Chinese Academy of Science South America Ctr. for Astronomy (CASSACA) (Chile); Thami El Halkouj, Zouhair Benkhaldoun, Univ. Cadi Ayyad (Morocco)
19 July 2022 • 10:50 - 11:10 | Room 520 b
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Hierarchical Fringe Tracking (HFT) on optical long baseline interferometry has performances set only by individual aperture sizes and independent from the number of telescopes. We have validated Integrated Optics HFT chips on an optical bench providing a realistic simulation of VLTI and CHARA interferometers. Combined with a very broad band active correction of chromatic OPD and differential refraction it will allow the VLTI to reach K magnitudes better than 12.5 on ATs and 16 on UTs. On-axis, it opens the imaging of complex disks around solar mass YSOs with ATs and the spectro-astrometry of hundreds of AGN BLRs in the J band with UTs. For MATISSE/VLTI, the sky coverage for off-axis tracking exceeds 80% within ±45° of the galactic plane and 15% on all the sky observable from Paranal, yielding a large sample of resolvable inner dust rims of AGN torus. We emphasize the potential of AGN science from 1 to 13 µm from a combination of an HFT with current and future VLTI instruments.
12183-18
Author(s): Narsireddy Anugu, CHARA Array, Georgia State Univ. (United States); John D. Monnier, Univ. of Michigan (United States); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Stefan Kraus, Univ. of Exeter (United Kingdom); Benjamin R. Setterholm, Univ. of Michigan (United States); Theo A. ten Brummelaar, Gail Schaefer, Cyprien Lanthermann, CHARA Array (United States); Jacob Ennis, Univ. of Michigan (United States)
19 July 2022 • 11:10 - 11:30 | Room 520 b
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MIRC-X and MYSTIC are six telescope all-in-one beam combiners at the CHARA array, Mount Wilson Observatory, USA. These two instruments make simultaneous cophasing observations in J + H + K-band wavelengths and deliver λ/2B~0.5 mas angular resolution imaging utilizing the world's largest baseline lengths ranging from 30-330 m. MIRC-X and MYSTIC are operated in two observing modes based on the target spectrum and their over-resolved nature: (i) primary-secondary and (ii) combined mode. In the primary-secondary mode, we use one instrument as a fringe tracker and the other as a science combiner to enable high spectral resolution interferometry. Higher visibility fringes are selected depending on their baseline length and wavelengths for robust fringe tracking for over-resolved objects in the combined mode. We installed four accelerometers to study vibrations on the beam combiner table to improve fringe tracking. We here report the instrument concepts and the first on-sky science results.
12183-19
Author(s): Marc-Antoine Martinod, Teresa Deyi Maria Klinner-teo, Peter G. Tuthill, Sydney Institute for Astronomy (Australia), Sydney Astrophotonic Instrumentation Labs. (Australia), Australian Astronomical Observatory, The Univ. of Sydney (Australia); Simon Gross, Elizabeth Arcadi, Glen Douglass, Jacinda Webb, Macquarie Univ. (Australia); Barnaby R. M. Norris, Sydney Institute for Astronomy (Australia), Sydney Astrophotonic Instrumentation Labs. (Australia), Australian Astronomical Observatory, The Univ. of Sydney (Australia); Olivier Guyon, National Astronomical Observatory of Japan (United States), Steward Observatory (United States), Astrobiology Ctr., National Institutes of Natural Sciences (Japan); Julien Lozi, National Astronomical Observatory of Japan (United States); Tiphaine Lagadec, Sydney Institute for Astronomy (Australia), Sydney Astrophotonic Instrumentation Labs. (Australia), Australian Astronomical Observatory, The Univ. of Sydney (Australia); Nemanja Jovanovic, Caltech (United States); Thomas Gretzinger, Michael J. Withford, Macquarie Univ. (Australia); Jon S. Lawrence, Australian Astronomical Observatory (Australia)
19 July 2022 • 11:30 - 11:50 | Room 520 b
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Nulling interferometry is one of the most promising techniques for imaging exoplanets at solar system scales as it simultaneously delivers the stringent requirements for contrast and angular resolution. The GLINT instrument has delivered significant advances in performance, and limitations have been identified: the compensation of remaining phase fluctuations and providing broadband null depth. The tricoupler offers to resolve these issues simultaneously. In this paper, we present these challenges and describe the modelling of devices to overcome them, the expected performance of a nuller based on these principles of phase control and null depth, and the laboratory characterization of 3D-written tricoupler.
12183-20
Author(s): Mohanakrishna Ranganathan, Adrian M. Glauser, Thomas Birbacher, Sascha P. Quanz, ETH Zurich (Switzerland)
19 July 2022 • 11:50 - 12:10 | Room 520 b
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Bracewell Nulling Interferometer is a promising technique to directly detect terrestrial exoplanets close to their host stars. Characterizing the atmosphere of such exoplanets is a key science goal of the future space based interferometer mission called LIFE. A prototype of LIFE is built in the lab to simulate the sensitivity and stability of the interferometer. This testbench is called NICE (Nulling Interferometer Cryogenic Experiment). The testbench is developed in two phases. The current paper summarizes the construction and performance of phase 1 of the instrument which operates in ambient conditions.
Session 4: Critical Subsystems II
19 July 2022 • 13:30 - 15:10
12183-21
Author(s): James H. Clark, U.S. Naval Research Lab. (United States); F. Ernesto Penado, Northern Arizona University (United States); Sergio R. Restaino, Henrique R. Schmitt, Ty Martinez, U.S. Naval Research Lab. (United States)
19 July 2022 • 13:30 - 13:50
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We show that the cumulative effect of slight concavity on all the NPOI beam transport mirror surfaces result in coherence loss by a factor of two. We also show that thermal drifts on mirrors located outside thermally controlled buildings, can result in large alignment drifts over the course of the night, especially when the long delay lines are in use. We discuss a couple approaches to overcome these issues: a static low order adaptive optics system to correct the concavity effects and an auto-alignment system. We also discuss the specifications of these systems and the proposed designs.
12183-22
Author(s): Sorabh Chhabra, Univ. of Exeter (United Kingdom); Michele Frangiamore, INAF - Osservatorio Astronomico di Brera (Italy); Stefan Kraus, Univ. of Exeter (United Kingdom); Andrea Bianco, INAF Osservatorio Astronomico di Brera (Italy); Francisco Garzon, Instituto de Astrofísica de Canarias (Spain); John D. Monnier, Univ. of Michigan (United States); Daniel J. Mortimer, Univ. of Exeter (United Kingdom)
19 July 2022 • 13:50 - 14:10
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The BIFROST instrument will be the first VLTI instrument optimised for high spectral resolution (up to R=25,000) and operate between 1.05 and 1.7 µm. A key component of the instrument will be the spectrograph, where we require a high throughput over a broad bandwidth. In this contribution, we will discuss the three planned spectral modes (R≈1000, R≈5000, and R≈25,000), the key spectral windows that we need to cover, and the technology choices that we consider. We will present our plan for using Volume Phase Holographic Gratings (VPHGs) to achieve a high efficiency > 85% and discuss a possible multiplexed design, where the YJ-band and H-band are arranged side-by-side on the BIFROST detector. We will present our preliminary optical design and our strategies for wavelength calibration.
12183-23
Author(s): Cyprien Lanthermann, Theo A. ten Brummelaar, CHARA Array, Georgia State Univ. (United States); Peter G. Tuthill, Marc-Antoine Martinod, Sydney Institute for Astronomy (Australia); Douglas R. Gies, Georgia State Univ. (United States); Gail Schaefer, Matthew D. Anderson, CHARA Array, Georgia State Univ. (United States)
19 July 2022 • 14:10 - 14:30
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Recent efforts have been made to improve the capabilities of optical interferometry, with instruments such as PIONIER and GRAVITY at VLTI, or MIRC-X and MYSTIC at CHARA. But none of them were designed specifically to push for sensitivity as their primary goal. Our goal is to build an instrument specifically designed to improve its sensitivity. To do this we used different recent progress in aspects of the design, such as the e-APD detector technology, a minimal number of optical elements, an image plane design, and innovative ideas for other parts of the design such as the use of an edge filter allowing simultaneous H- and K-band observation. Due to our focus on sensitivity, we chose to limit our design to 3 beams. We use a low spectral resolution, allowing for group delay fringe tracking but maximizing the SNR of the fringes for each spectral channel. All these elements will lead to a limit magnitude between 10 and 11 in both H- and K-band.
12183-24
Author(s): Anders M. Jorgensen, New Mexico Institute of Mining and Technology (United States); Khristian Jones, David Noble, Lowell Observatory (United States); James H. Clark, Henrique R. Schmitt, U.S. Naval Research Lab. (United States); Gerard T. van Belle, Lowell Observatory (United States)
19 July 2022 • 14:30 - 14:50
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The Navy Precision Optical Interferometer (NPOI) is approaching 30 years of operational life. During that time it has carried out many observations of single and multiple star systems, and has seen upgrades to subsystems and expansion of capabilities. For the last couple of years there has been a major ongoing effort to expand the capabilities of the NPOI with new telescopes, new instruments, and completion of the bootstrapping and imaging capability that was part of the original NPOI design. As part of this upgrade we are also upgrading and replacing some electronic systems. Some technologies which were state-of-the art, e.g. VxWorks, have over the years been overtaken by inexpensive systems such as embedded microcontroller, consumer-grade compact system such as Raspberry Pi and Arduinos, and inexpensive manufacture of simple but powerful custom PCBs. This makes it possible to incorporate remote controls of actuators which so-far have required an adjacent operator.
12183-25
Author(s): James J. D. Luis, David F. Buscher, John S. Young, Christopher A. Haniff, Xiaowei Sun, Univ. of Cambridge (United Kingdom); Christopher Salcido, Madgalena Ridge Observatory, New Mexico Institute of Mining and Technology (United States); Michelle J. Creech-Eakman, Magdalena Ridge Observatory, New Mexico Institute of Mining and Technology (United States)
19 July 2022 • 14:50 - 15:10
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The Magdalena Ridge Observatory Interferometer (MROI) will soon deploy an Automated Alignment System (AAS) to cap visibility losses due to beam misalignment at ~1%. Recently we established a comprehensive error budget that quantifies modes by which misalignment enters the interferometer. This paper compares the results of factory acceptance tests for three key components of the AAS (two light sources and a detector) against requirements derived from the error budget. Finally, we look ahead to site acceptance tests using the first two beamlines of MROI in the second half of 2022.
Session 5: Observing Techniques I
19 July 2022 • 15:40 - 18:10 | Room 520 b
Session Chair: Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
12183-26
Author(s): Peter G. Tuthill, The Univ. of Sydney (Australia)
19 July 2022 • 15:40 - 16:10 | Room 520 b
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This invited review talk covers the field of Aperture Masking Interferometry (AMI). Current instruments and science domains spanning the astrophysical spectrum from young stars to evolved, and from exoplanets to supergiants are described. AMI has also inspired extension into new domains of operation such as polarimetric interferometry, and next-generation optical implementations such as photonic pupil remapping interferometers. Of particular promise is the AMI mode now flying on JWST as one of the supported operational modes of the NIRISS instrument. Aboard such a powerful platform, the AMI mode will deliver the most advanced and scientifically capable interferometer yet launched into space.
12183-27
Author(s): Sébastien B. Vievard, Vincent Deo, Subaru Telescope, NAOJ (United States); Elsa Huby, Sylvestre Lacour, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique (France), Observatoire de Paris (France); Olivier Guyon, Subaru Telescope, NAOJ (United States); Nick Cvetojevic, Observatoire de la Côte d'Azur (France); Kevin Barjot, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique (France), Observatoire de Paris (France); Guillermo Martin, Univ. Grenoble Alpes (France); Manon Lallement, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique (France), Observatoire de Paris (France); Julien Lozi, Subaru Telescope, NAOJ (United States); Takayuki Kotani, Astrobiology Ctr., National Institute of Natural Sciences (Japan); Franck Marchis, SETI Institute (United States); Daniel Rouan, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique (France), Observatoire de Paris (France); Kyohoon Ahn, Nour Skaf, Subaru Telescope, NAOJ (United States); Guy Perrin, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique (France), Observatoire de Paris (France)
19 July 2022 • 16:10 - 16:30 | Room 520 b
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FIRST is a post Extreme Adaptive-Optics (ExAO) spectro-interferometer based on pupil remapping using single-mode fibers. Installed on the SCExAO platform at the Subaru Telescope, it operates in the Visible (600-800nm, R 400) and demonstrated companion detection below the telescope diffraction limit. As an interferometric device, FIRST is sensitive to phasing problems in the telescope pupil. This is particularly interesting to measure discontinuous aberrations, invisible to the ExAO sensors. Recent developments aimed to measure upstream aberrations directly from the same interferometric signal used for scientific data analysis. A key limitation to this new capability is the fiber thermal and mechanical instabilities, inducing up to 1 micron drift over a few seconds. We propose to use a metrology laser source, allowing to discriminate FIRST instrumental effects from all the upstream aberrations. We present the integration of this setup and the on-sky demonstration of the method.
12183-28
Author(s): Guillaume Bourdarot, Felix Widmann, Frank Eisenhauer, Sebastiano von Fellenberg, Stefan Gillessen, GRAVITY+ Collaboration, Max-Planck-Institut für extraterrestrische Physik (Germany)
19 July 2022 • 16:30 - 16:50 | Room 520 b
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The unique astrometric capability of GRAVITY has already resulted in a serie of transformational results, from the study of the Galactic Center to the characterization of exoplanets. Nonetheless, these breakthroughs have not yet reached the ultimate noise limits of interferometric astrometry, and are currently limited by the systematics of the instrument. As part of the GRAVITY+ project, a major goal is to keep pushing the performances down to the precision of 10-30µas. In this talk, we present the on-going analysis of the precision limits of GRAVITY astrometry, and the potential solutions envisioned to overcome its systematics.
12183-29
Author(s): Antonia Drescher, Maximilian Fabricius, GRAVITY+ Collaboration, Frank Haussmann, Max-Planck-Institut für extraterrestrische Physik (Germany); Christian Straubmeier, Matthew Horrobin, Univ. zu Köln (Germany); Julien Woillez, European Southern Observatory (Germany); Pierre Bourget, European Southern Observatory (Chile); Frank Eisenhauer, Felix Widmann, Jinyi Shangguan, Taro Shimizu, Stefan Gillessen, Max-Planck-Institut für extraterrestrische Physik (Germany); Jean-Baptiste Le Bouquin, Univ. Grenoble Alpes (France); Thibaut Paumard, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique (France); Paulo J. V. Garcia, Univ. do Porto (Portugal); Laura Kreidberg, Max-Planck-Institut für Astronomie (Germany)
19 July 2022 • 16:50 - 17:10 | Room 520 b
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As part of the GRAVITY+ project, GRAVITY is currently undergoing a series of significant upgrades to further improve its performance and sky coverage. The instrumental changes will be transformational, and for instance uniquely position GRAVITY to observe the broad line region of hundreds of z ~2 AGN. The increased sky coverage is achieved by enlarging the maximum angular separation between the celestial science object and the off-axis fringe tracking object from currently 2 arcseconds up to unprecedented 30 arcseconds (limited by the atmospheric conditions), now demonstrated at the 8m telescopes for the first time.
12183-30
Author(s): Felix Widmann, Stefan Gillessen, Thomas Ott, Senol Yazici, Frank Eisenhauer, GRAVITY+ Collaboration, Max-Planck-Institut für extraterrestrische Physik (Germany)
19 July 2022 • 17:10 - 17:30 | Room 520 b
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With the upgrade from GRAVITY to GRAVITY+ the instrument will evolve to an all-sky interferometer, with the goal to observe extremely faint targets such as high redshift AGN. To make this possible we need to reduce the backscattering of the metrology laser, as this is currently the dominant noise source in GRAVITY. This is done in a new faint observing mode, where we damp the metrology light during the science observation to increase the SNR. Here we present the complete setup and implementation of GRAVITY faint, together with the first results of the new observing mode.
12183-31
Author(s): Nicolas Pourré, Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Julien Woillez, European Southern Observatory (Germany); Lucie Leboulleux, Alexis Carlotti, Institut de Planétologie et d’Astrophysique de Grenoble (France); Mathias Nowak, Institute of Astronomy, Univ. of Cambridge (United Kingdom); Sylvestre Lacour, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique (France), Observatoire de Paris (France)
19 July 2022 • 17:30 - 17:50 | Room 520 b
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Since 2019, GRAVITY has obtained unprecedented direct observations of exoplanets at high contrasts (down to 8×10^-5) and small angular separations from the host star (down to 110 mas). To access deeper contrast (10^-6) at smaller angular separations (100 mas), we propose to dig a dark hole at the planet position. It relies on wavefront control using the adaptive optics deformable mirror to minimize the stellar flux injected in the GRAVITY interferometric combiner. We demonstrate the implementation of this dark hole both in simulation and on the instrument at VLTI.
12183-37
Author(s): Simon Verlinden, Romain Laugier, Marc-Antoine Martinod, KU Leuven (Belgium); Bertrand Mennesson, Jet Propulsion Lab., NASA (United States); Denis Defrère, KU Leuven (Belgium)
19 July 2022 • 17:50 - 18:10 | Room 520 b
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Nulling interferometry is limited by its sensitivity to instrumental errors. Nulling self-calibration tries to reduce this by fitting the distribution of the measured data to the distribution of parametric models that include instrumental noise. However, the modeled distributions are approximated by Monte Carlo simulations, which results in a slow and inaccurate model fitting process. Our approach alleviates this problem by using an analytical expression of the model distributions that renders the cost function deterministic and makes the model fitting process faster and more reliable. We explore the parameter space and locate the regions of degeneracy for synthetic and LBTI datasets.
Session 6: Observing Techniques II
20 July 2022 • 10:30 - 12:10
12183-32
Author(s): Benjamin R. Setterholm, John D. Monnier, Univ. of Michigan (United States); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Claudia Paladini, Julien Woillez, Gérard Zins, European Southern Observatory (Chile); Jacob Ennis, Univ. of Michigan (United States); Keith J. C. Johnson, Univ. of Wisconsin-Madison (United States); Aaron Labdon, European Southern Observatory (Chile); Stefan Kraus, Univ. of Exeter (United Kingdom); Theo A. ten Brummelaar, CHARA Array, Georgia State Univ. (United States)
20 July 2022 • 10:30 - 10:50
12183-33
Author(s): Markus Wittkowski, Giacomo Beccari, Thomas Bierwirth, European Southern Observatory (Germany); Stéphane Brillant, European Southern Observatory (Chile); Paula C. Correia dos Santos, European Southern Observatory (Germany); Olivier Hainaut, Xavier Haubois, European Southern Observatory (Chile); Christian Hummel, Stéphane Marteau, Antoine Mérand, European Southern Observatory (Germany); Steffen Mieske, European Southern Observatory (Chile); Sangeeta Mysore, European Southern Observatory (Germany); Claudia Paladini, European Southern Observatory (Chile); Ferdinando Patat, John Pritchard, Michael Pruemm, Marina Rejkuba, Konrad R. W. Tristram, European Southern Observatory (Germany)
20 July 2022 • 10:50 - 11:10
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ESO’s VLT interferometer (VLTI) is a general-user optical/infrared interferometric facility. Its operations scheme is fully integrated into the well-established scheme of all VLT instruments and profits enormously from this experience and the implemented infrastructure to offer a unique service to the community. Taking advantage of a further development of ESO’s Observation Handling Tools, we have evolved the VLTI operations scheme as well. We have offered to VLTI investigators the possibility to indicate baseline configurations in a more flexible way and have introduced nested scheduling containers to better formalize the observational strategy. We have prepared for dedicated support of different types of interferometric observations. For imaging observations specifically, we have introduced an improved workflow to fill the uv plane and to handle time-critical imaging. We will describe this evolution of VLTI science operations and provide an outlook to further improvements.
12183-34
Author(s): Florentin Millour, Philippe Bério, Alexis Matter, Olivier Lai, Stéphane Lagarde, Univ. Côte d'Azur (France); Julien Woillez, European Southern Observatory (Germany); Romain G. Petrov, James H. Leftley, Univ. Côte d'Azur (France); Thibaut Paumard, Observatoire de Paris (France); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Sylvestre Lacour, Observatoire de Paris (France); Abdelkarim Boskri, LPHEA (Morocco)
20 July 2022 • 11:10 - 11:30
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GRAVITY+ is made to perform best in the K-band (2-2.4 micron wavelength range), allowing one to achieve extraordinary science on AGNs and exoplanets. We explore here another enabling feature that GRAVITY+ will allow one to do: get better science done with the MATISSE instrument. Two science aspects will gain from the new AO and the off axis capability of GRAVITY+: exoplanets and AGNs. On exoplanets, the future narrow-field off axis capability of GRA4MAT and the gain the new GPAO will bring to wavefront correction will enable one to characterize a handful of exoplanets in the L band. On AGNs, off axis tracking in the K band while recording science data in the L and N bands will enable one to image the dusty torus-like structure around the central engine of many AGNs, giving additional characteristics like inclination angle to these still enigmatic powerful sources of energy in the close and not-so close universe.
12183-35
Author(s): Tyler Gardner, John D. Monnier, Univ. of Michigan (United States); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Francis C. Fekel, Tennessee State Univ. (United States); Stefan Kraus, Univ. of Exeter (United Kingdom); Narsireddy Anugu, Theo A. ten Brummelaar, CHARA Array, Georgia State Univ. (United States); Claire L. Davies, Univ. of Exeter (United Kingdom); Jacob Ennis, Univ. of Michigan (United States); Michael J. Ireland, Australian National Univ. (Australia); Aaron Labdon, European Southern Observatory (Chile); Cyprien Lanthermann, Gail Schaefer, CHARA Array, Georgia State Univ. (United States); Benjamin R. Setterholm, Univ. of Michigan (United States)
20 July 2022 • 11:30 - 11:50
12183-36
Author(s): Marc-Antoine Martinod, Azzurra Bigioli, KU Leuven (Belgium); Julia Bryant, Sydney Institute for Astronomy (Australia); Denis Defrère, KU Leuven (Belgium); Michael J. Ireland, The Australian National Univ. (Australia); Stefan Kraus, Univ. of Exeter (United Kingdom); Tiphaine Lagadec, Sydney Institute for Astronomy (Australia); Romain Laugier, KU Leuven (Belgium); Frantz Martinache, Observatoire de la Côte d'Azur (France); Daniel J. Mortimer, Sorabh Chhabra, Univ. of Exeter (United Kingdom)
20 July 2022 • 11:50 - 12:10
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We introduce to the VLTI the new concept of Asgard: an instrumental suite including four natively collaborating instruments: BIFROST, a stellar interferometer dedicated to the study of the formation of multiple systems; Hi-5, a nulling interferometer dedicated to image young nearby planetary systems in the M band; Heimdallr, an all-in-one instrument performing both fringe tracking and stellar interferometry with the same optics; Baldr, a fibre-injection optimiser. These instruments share common goals and technologies. The idea is to make the instruments interoperable to deliver unprecedented sensitivity and accuracy from J to M bands, thanks to uniformised observing and data processing strategies.
Session 7: Technologies
20 July 2022 • 13:30 - 17:40 | Room 520 b
Session Chair: Antoine Mérand, European Southern Observatory (Germany)
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Author(s): Lucas Labadie, Univ. zu Köln (Germany)
20 July 2022 • 13:30 - 14:00 | Room 520 b
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In this contribution, I will review the current state of the art regarding the interplay between photonic-based solutions and astronomical instrumentation and highlight the growth of the field, as well as its recognition in recent strategy surveys such as the Decadal. I will explain the benefits of different technological platforms making use of photolithography or laser-writing techniques. I will review the most recent results in the field covering theoretical/simulation, laboratory characterization and on-sky prototyping. Astrophotonics may have a unique role to play in the forthcoming era of new ground-based astronomical facilities, and possibly in the field of space science. The VLTI has been one of the pioneering astronomical infrastructure to exploit the potential of astrophotonics instrumentation for high-angular resolution interferometric observations, whereas new opportunities will arise in the context of the future ELTs.
12183-39
Author(s): Guillaume Bourdarot, Max-Planck-Institut für extraterrestrische Physik (Germany)
20 July 2022 • 14:00 - 14:30 | Room 520 b
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The recombination of a large number of telescopes in an imaging array represents a major challenge of infrared astronomy, calling for active instrumental research. In the mid-infrared, as initiated in the early 1980s, heterodyne interferometry offers a potential path in complement to classical inteferometry, despite a lower sensitivity. In this review, we present the current status of heterodyne interferometry. After recalling its basic working principles and the motivation for its use, we present the impact of current technological developments on the building blocks of a heterodyne interferometer, and the associated projects in this field. Finally, we focus on the interest of developping pathfinders of imaging interfermotric instrument, and the possible synergies with classical interferometry.
12183-40
Author(s): Jean-Philippe Berger, Institut de Planétologie et d’Astrophysique de Grenoble (France), Univ. Grenoble Alpes (France), CNRS (France); Guillaume Bourdarot, Institut de Planétologie et d’Astrophysique de Grenoble (France), Max-Planck-Institut für extraterrestrische Physik (Germany); Tituan Allain, Institut de Planétologie et d’Astrophysique de Grenoble (France), Univ. Grenoble Alpes (France), CNRS (France); Hugues Guillet de Chatellus, Lab. Interdisciplinaire de Physique (France), Univ. Grenoble Alpes (France), CNRS (France)
20 July 2022 • 14:30 - 14:50 | Room 520 b
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We present the characterization of a complete photonics correlation scheme for mid-infrared heterodyne interferometry. The bench can handle very high bandwidths RF signals generated by the heterodyne beating of celestial light with a local oscillator on future generation mid-infrared detectors. The bench is composed of a first two-beam stage allowing the mixing of the "science" source with the local oscillator and a second photonics correlation stage made with telecom components. We present the characterization of the coherence measurement chain performance. Several possible photonics correlation concepts including a patented double loop correlation are introduced. We finally discuss possible implementations at VLTI.
12183-41
Author(s): Jacopo Siliprandi, Heriot-Watt Univ. (United Kingdom); David G. MacLachlan, Calum A. Ross, Scottish Universities Physics Alliance, Heriot-Watt Univ. (United Kingdom); Tarun K. Sharma, Lucas Labadie, Univ. zu Köln (Germany); Kalaga V. Madhav, Abani Shankar Nayak, Aline N. Dinkelaker, Martin M. Roth, Leibniz-Institut für Astrophysik Potsdam (Germany); Ettore Pedretti, UK Research and Innovation (United Kingdom), STFC Rutherford Appleton Lab. (United Kingdom); Theo A. ten Brummelaar, Nicholas Scott, CHARA Array, Georgia State Univ. (United States); Vincent Coudé du Foresto, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris (France), CNRS (France), Univ. Paris Diderot (France); Robert R. Thomson, Aurélien Benoît, Scottish Universities Physics Alliance, Heriot-Watt Univ (United Kingdom)
20 July 2022 • 14:50 - 15:10 | Room 520 b
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Integrated optics beam combiners offer assets through compact design, stability, and number of telescope inputs, but present also hurdles for wavelengths beyond 2.0 μm. We explore the use of ultrafast laser inscription to fabricate 3D waveguide structures and report on low loss transmission two-telescope K-band beam combiner in Infrasil glass. The combiner is composed of three directional asymmetric couplers over the K-band: one 3 dB coupler for interferometric measurements and two photometric taps with splitting ratios of 75:25. We will present our latest work developing a two-telescope K-band beam combiner for the JouFLU instrument at the CHARA array
12183-42
Author(s): Tituan Allain, Jean-Philippe Berger, Institut de Planétologie et d’Astrophysique de Grenoble (France); Carlo Sirtori, Lab. de Physique de l'Ecole Normale Supérieure (France)
20 July 2022 • 15:10 - 15:30 | Room 520 b
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One one the major challenges of mid-infrared astronomical heterodyne interferometry is its sensitivity limitations. Detectors capable of handling several 10GHz bandwidths have been identified as key building blocks of future instruments. Quantum cascade technologies based on heterostructures have recently demonstrated their ability to provide such performances. In this work we characterize state-of-the-art Quantum Cascade Detectors in terms of noise, dynamic range and bandwidth in a non-interferometric heterodyne set-up. We discuss the possibility to use them on astronomical systems to measure the beating between the local oscillator and the astronomical signal.
12183-43
Author(s): Ahmed Sanny, Univ. zu Köln (Germany), MQ Photonics Research Ctr., Macquarie Univ. (Australia); Lucas Labadie, Univ. zu Köln (Germany); Simon Gross, MQ Photonics Research Ctr., Macquarie Univ. (Australia); Denis Defrère, Azzurra Bigioli, KU Leuven (Belgium); Romain Laugier, Institute of Astronomy (Belgium); Thomas Gretzinger, Michael J. Withford, MQ Photonics Research Ctr., Macquarie Univ. (Australia)
20 July 2022 • 16:00 - 16:20 | Room 520 b
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A 4-telescope photonic beam combiner is at the heart of the Hi-5 instrument for performing nulling interferometry to detect faint exoplanetary signals in the mid-infrared L’ band. We report here on the prototype combiner, including technical requirements and design that has been manufactured by ultrafast laser inscription in a Gallium-Lanthanum-Sulphide glass substrate and examined on our 4-beam spectro-interferometric lab bench, the throughput of the nulling beam combiners, the chromatic and broadband coupling ratios in the 3.6-3.9µm range for the couplers and the Y-junctions, as well as the broadband interferometric properties of these 4-telescope mid-infrared photonic combiners has been characterized.
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Author(s): Egle Zemaityte, Ian Baker, Dan Owton, Vincent Isgar, Les Hipwood, Chris Maxey, Matthew Hicks, Peter Thorne, Keith Barnes, Leonardo UK Ltd. (United Kingdom)
20 July 2022 • 16:20 - 16:40 | Room 520 b
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Linear-mode, avalanche photodiode arrays (LmAPDs) based on bandgap engineered HgCdTe, grown by Metal Organic Vapour Phase Epitaxy (MOVPE) are used in low-flux applications, where the signal-to-noise ratio would otherwise be very low. Saphira (320×256/24 µm) devices have been characterised at the University of Hawaii and ESO, providing an independent assessment of the current performance envelope. These devices have been deployed as wavefront sensors for adaptive optic systems in nine major telescopes. Large format arrays are now in development and characterisation stages. A 512×512/24 µm device, with a quadrant architecture, specifically for pyramid wavefront sensors, is currently under development for the ELT. 1k×1k/15 µm and 2k×2k/15 µm devices are being developed to meet the very low dark current requirement. High speed devices with sub-ns response for free space optical communications and LIDAR applications are also being designed.
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Author(s): Nick Cvetojevic, Frantz Martinache, Peter Marley Chingaipe, Observatoire de la Côte d'Azur (France); Romain Laugier, KU Leuven (Belgium); Mamadou N'Diaye, Roxanne Ligi, Observatoire de la Côte d'Azur (France); David Mary, Observatoire de la Côte d’Azur (France)
20 July 2022 • 16:40 - 17:00 | Room 520 b
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One of the largest limitations faced by nulling interferometers is their extreme sensitivity to any residual optical path differences between the incoming telescope beams induced by the atmosphere, even after adaptive optics or fringe-tracker correction. Here, we present laboratory characterization of active phase-actuators built into a photonic chip containing nulling interferometers in the H-band. Utilizing the thermo-optic effect to actively control the phase delay in the waveguides, we present their performance in terms of accuracy, chromaticity, response time, and stability. We also measure a response time of less than 1ms, and a reproducibility to less than 0.5 degrees of phase (2 nm of optical path). We show a closed-loop demonstration of on-chip piston correction by using the flux measured on multiple ‘bright’ outputs of a Multimode Interference coupler based nuller to servo upstream phase actuators.
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Author(s): Peter Marley Chingaipe, Frantz Martinache, Nick Cvetojevic, Observatoire de la Côte d'Azur (France)
20 July 2022 • 17:00 - 17:20 | Room 520 b
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One of the most difficult challenges in modern astronomy is the detection of exoplanets and the spectral characterization of their atmospheres using direct imaging. Long-baseline nulling interferometry is a promising solution to meet this challenge as it provides high angular resolution at high-contrasts. A novel technique called kernel-nulling provides these advantages with the added benefit of calibrating out the piston perturbations due to the atmosphere. Here, we present the first laboratory characterization results of a four-input photonic kernel-nuller in the near-infrared.
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Author(s): Thomas Birbacher, ETH Zürich (Switzerland); Adrian M. Glauser, Mohanakrishna Ranganathan, Sascha P. Quanz, ETH Zurich (Switzerland)
20 July 2022 • 17:20 - 17:40 | Room 520 b
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An accurate metrology system is required to stabilize the path lengths in the Nulling Interferometry Cryogenic Experiment (NICE) to within 0.45 nm to achieve broadband mid-infrared nulls with long exposure times, which are required for potential future space missions that aim to image terrestrial exoplanets. For this purpose, a heterodyne laser distance metrology is developed to enable differential path length measurements that are stable over multiple days with sub-nanometer accuracy at a bandwidth of 1 kHz. While similarly accurate metrologies have already been demonstrated, this work aims to solve several challenges that arise in the context of NICE, such as the need for long-term stability, the high intensity attenuation through the NICE beam path, and the requirement that the metrology shall be able to deliver low-latency feedback for closed-loop operation to compensate vibrations and drift of the nulling testbed.
Session 8: Space Interferometry Technology
21 July 2022 • 10:30 - 12:10 | Room 520 b
Session Chair: Stephanie Sallum, Univ. of California, Irvine (United States)
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Author(s): Jonah T. Hansen, Michael J. Ireland, Tony Travouillon, Michael Ellis, Shanae King, Tiphaine Lagadec, Joice Mathew, Patrick Miller, Adam Rains, Hancheng Shao, The Australian National Univ. (Australia)
21 July 2022 • 10:30 - 10:50 | Room 520 b
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Optical interferometry from space is arguably the most exciting prospect for high angular resolution astrophysics; including the analysis of exoplanet atmospheres. This was highlighted in the recent ESA Voyage 2050 plan, which pointed out the exciting potential of this technology, but also indicated the critical need for technological demonstrators. Here we present the Pyxis interferometer; a ground-based pathfinder for a CubeSat space interferometer, currently being built at Mt Stromlo Observatory. We outline its technological and scientific potential as the only visible wavelength interferometer in the Southern Hemisphere, and the optical systems designed to provide CubeSat compatible metrology for formation flying.
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Author(s): Samuel Wade, Jonah T. Hansen, Michael J. Ireland, Tony Travouillon, Nicholas Bohlsen, Logan Corry, Nicholas Herrald, Weihao Luo, Stephen Madden, Joseph Mangos, Michael Polkinghorne, Kunlun Yan, The Australian National Univ. (Australia)
21 July 2022 • 10:50 - 11:10 | Room 520 b
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The Pyxis interferometer is a ground-based pathfinder for an optical space interferometer being built at Mt Stromlo Observatory. In this second paper, we discuss the system breakdown of the interferometer and its mechanical design. We outline the interferometer’s three robotic platforms, with two telescopic collectors and one central beam combiner. Each collector utilises a fully Aluminium diamond turned telescope, designed to remove thermal distortions for future space applications. We also explain the chosen control system for the interferometer and how it will be used to ensure the linear and angular control requirements, including sub-milli-radian angular control of each robot.
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Author(s): Gerard T. van Belle, Lowell Observatory (United States); Daniel Hillsberry, Jessica Piness, Justin Kugler, Kevin DiMarzio, Redwire Space, Inc. (United States)
21 July 2022 • 11:10 - 11:30 | Room 520 b
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Astrophysical goals articulated in the recent Astronomy Decadal Review demand significant strides in high sensitivity, high spatial resolution observing. Current ground-based interferometric observatories have validated and demonstrated synthetic aperture observing, but are fundamentally limited in sensitivity by the earth's atmosphere. Lowell Observatory and Redwire Space, Inc., have recently concluded NASA SBIR Phase II work in developing 'Optimast' interferometry technologies which provide us with a toolkit for mission development. Optimast research included demonstrations of a prototype beam combiner, outboard feed optics tracking, and in-situ boom manufacturing for structurally connected free fliers. Our missions roadmap include affordable small demonstrators such as free fliers for flexible at-will observing of the entire sky, and lunar surface 'suitcase' concepts for rapid, simple implementation of sensitive high resolution facilities.
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Author(s): Leonid Pogorelyuk, Paul Serra, Shreeyam Kacker, Massachusetts Institute of Technology (United States); Gioia Rau, Kenneth G. Carpenter, NASA Goddard Space Flight Ctr. (United States); Laurent Pueyo, Space Telescope Science Institute (United States); John D. Monnier, Univ. of Michigan (United States); Ewen Douglas, The Univ. of Arizona (United States); Kerri Cahoy, Massachusetts Institute of Technology (United States)
21 July 2022 • 11:30 - 11:50 | Room 520 b
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The mirrors of astronomical interferometers need to be aligned within a fraction of a wavelength relative to one another. This would be especially challenging for mirrors separated by hundreds of meters flying in Earth’s orbit. However, precise alignment could potentially be maintained for hours when flying a laser guide star in front of the interferometer that is arranged in a specific orbital-optical configuration. In this work, we analyze the theoretical performance of a CubeSats Laser-Guided Space Interferometer. We also estimate the performance of imaging stellar surfaces given perfect wavefront control.
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Author(s): Felix Dannert, ETH Zurich (Switzerland), National Ctr. of Competence in Research PlanetS (Switzerland); Sascha P. Quanz, ETH Zurich (Switzerland); Jens Kammerer, Space Telescope Science Institute (United States); Adrian M. Glauser, ETH Zurich (Switzerland); Romain Laugier, KU Leuven (Belgium); Andrea Fortier, Ctr. for Space and Habitability (CSH), Univ. Bern (Switzerland); Mohanakrishna Ranganathan, ETH Zurich (Switzerland)
21 July 2022 • 11:50 - 12:10 | Room 520 b
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The Large Interferometer For Exoplanets (LIFE) is a proposed mission concept for a space-based nulling interferometer to directly detect and characterize terrestrial exoplanets in the mid-infrared. LIFE's capability to observe a statistically relevant sample of terrestrial planets in the habitable zone is supported by yield predictions based on exoplanet statistics obtained from the Kepler space mission. So far, these predictions have not included instrumental noise. As the concept of mid-IR nulling interferometry is known to be sensitive to instrumental noise, we extend the yield simulator by an instrumental noise model. The updated yield results allow us to estimate the systematic impact of instrumental noise on LIFEs discovery space and aids in constraining basic technical requirements.
Session 9: Data Processing Analysis Access and Discovery
21 July 2022 • 13:30 - 17:50 | Room 520 b
Session Chair: Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
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Author(s): Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico); Antoine Mérand, European Southern Observatory (Germany); Stephanie Sallum, Univ. of California, Irvine (United States)
21 July 2022 • 13:30 - 14:00 | Room 520 b
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Interferometric image reconstruction has become an important asset for astrophysical studies during the last decades. This has been mainly due to improvements in the imaging capabilities of existing interferometers such as the second generation of beam combiners, MATISSE and GRAVITY, at the Very Large Telescope Interferometer; or the expected facilities like the Sparse Aperture Masking mode of the James Webb Space Telescope. Since 2004, the community has organized a biennial contest to formally test the different methods and algorithms for image reconstruction. In 2022, we celebrated the 9th edition of the "Interferometric Imaging Contest". This initiative represents an open call for the different scientific groups to present their advances in the field of interferometric image reconstruction with sparse infrared arrays. This contest represents a unique opportunity to benchmark, the current advances and limitations in the field, as well as to discuss possible future approaches
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Author(s): Férréol Soulez, Ctr. de Recherche Astrophysique de Lyon, Observatoire de Lyon (France); Laurent Bourgès, Univ. Grenoble Alpes (France), CNRS (France), Observatoire des Sciences de l'Univers de Grenoble (France); Antoine Kaszczyc, Ctr. de Recherche Astrophysique de Lyon, Observatoire de Lyon (France); Guillaume Mella, Univ. Grenoble Alpes (France), CNRS (France), Observatoire des Sciences de l'Univers de Grenoble (France); Martin Pratoussy, Ctr. de Recherche Astrophysique de Lyon, Observatoire de Lyon (France); Gilles Duvert, Univ. Grenoble Alpes (France), CNRS (France), Institut de Planétologie et d’Astrophysique de Grenoble (France)
21 July 2022 • 14:00 - 14:20 | Room 520 b
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In interferometry, the quality of the reconstructed image depends on the algorithm used and its parameters, and users often need to compare the results of several softwares to disentangle artifacts from actual features of the astrophysical object. Such comparisons can rapidly become cumbersome, as these softwares are very different. OImaging is a graphical interface intended to be a common frontend to image reconstruction softwares. With OImaging, the user can now perform multiple reconstructions within a unique interface. From a given dataset, OImaging allows to benchmark different image reconstruction softwares and assess the reliability of the image reconstruction process.
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Author(s): Julia Stadler, GRAVITY+ Collaboration, Antonia Drescher, Felix Mang, Frank Eisenhauer, Max-Planck-Institut für extraterrestrische Physik (Germany)
21 July 2022 • 14:20 - 14:40 | Room 520 b
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The GRAVITY near-IR interferometer allows to observe the Galactic Center at very high angular resolution and to precisely track stellar orbits around Sagittarius A*. In the context of testing General Relativity close to the supermassive black hole, deep imaging is essential to search for faint stars on potentially short orbits. Here, we present G^R , a new imaging tool specifically designed for Galactic Center observations with GRAVITY. The algorithm is based on a Bayesian interpretation of the imaging problem, formulated in the framework of Information Field Theory and builds upon existing work from radio-interferometric imaging. Its application to GRAVITY observations from 2021 yields the deepest images of the Galactic Center on scales of a few milli-arcseconds, to date. Apart from detecting the known stars S38, S42, S60 and S63 within the central 100 mas around Sagittarius A*, the discovery of S300, a faint star moving at high angular velocity, demonstrates the capability of our met
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Author(s): Barnaby R. M. Norris, Marc-Antoine Martinod, Peter G. Tuthill, The Univ. of Sydney (Australia); Simon Gross, Macquarie Univ. (Australia); Nick Cvetojevic, Observatoire de la Côte d'Azur (France); Nemanja Jovanovic, Caltech (United States); Tiphaine Lagadec, Teresa Deyi Maria Klinner-teo, The Univ. of Sydney (Australia); Olivier Guyon, Julien Lozi, Vincent Deo, Sébastien B. Vievard, National Astronomical Observatory of Japan (United States); Alex Arriola, Thomas Gretzinger, Jon S. Lawrence, Michael J. Withford, Macquarie Univ. (Australia)
21 July 2022 • 14:40 - 15:00 | Room 520 b
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Photonic technologies have enabled a new generation of nulling interferometers, but the achievable starlight suppression is only as good as the instrument’s wavefront control, and its accuracy is only as good as its calibration. Here we present a new approach wherein a deep neural network is used to learn the true in-situ complex transfer function of the instrument. Then, using data from non-nulled outputs of the nulling chip, it predicts the instrumental leakage contribution (at millisecond timescales) for the nulled outputs, enabling accurate calibration and fringe tracking. A demonstration using GLINT on-sky observations will also be presented.
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Author(s): Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico); Antxon Alberdi, Rainer Schödel, Instituto de Astrofísica de Andalucía (Spain); Anand Sivaramakrishnan, Space Telescope Science Institute (United States); Abel Rosales, Univ. Nacional Autónoma de México (Mexico)
21 July 2022 • 15:00 - 15:20 | Room 520 b
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Imaging is the most intuitive way to analyze interferometric data, recovering images from sparsely sampled visibilities is challenging because infrared interferometers are restricted to sparse arrays of only a few telescopes. Furthermore, the atmosphere constraints the phase retrieval. Therefore, infrared interferometric imaging is still an open field of research. In this contribution, we present the capabilities of our software CASSINI to perform interferometric image reconstruction based on Compressed Sensing and machine learning. CASSINI is an open source code with tools for interferometric analysis, including Principal Component Analysis of reconstructed images and their impact on the interferometric observables in the Fourier plane. The capabilities and performance of the software will be presented through reconstructed images of both simulated (JWST-SAM) and real interferometric data (GRAVITY-VLTI) of proto-planetary disks and bow shocks in massive stars.
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Author(s): Roxanne Ligi, Frantz Martinache, Univ. Côte d'Azur (France), Observatoire de la Côte d'Azur (France), CNRS (France); David Mary, Univ. Côte d'Azur (France), Observatoire de la Côte d’Azur (France), CNRS (France); Mamadou N'Diaye, Nick Cvetojevic, Peter Marley Chingaipe, Univ. Côte d'Azur (France), Observatoire de la Côte d'Azur (France), CNRS (France); Romain Laugier, KU Leuven (Belgium)
21 July 2022 • 15:50 - 16:10 | Room 520 b
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Kernel-phase analysis is a method based on the generalization of closure phases that requires a precise discrete modeling of the pupil acting as a virtual interferometer. A projection operation applied to the Fourier phase makes kernel-phases observables in principle free from aberration, giving access to a better contrast between star and planet, at shorter orbital separation. We present new results using kernels that take into account field rotation. We also built and analyzed specific statistical tests to obtain new results, in particular the confirmation and quantification of the detection of a companion. We applied it to SPHERE/VLT data using a Sparse Aperture Masking: we quantified the detection of HD124527's companion in terms of significance level and provided a confidence interval on its position.
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Author(s): Alexander Chaushev, Stephanie Sallum, Univ. of California, Irvine (United States); Jeffrey Chilcote, Univ. of Notre Dame (United States); Tyler Groff, NASA Goddard Space Flight Ctr. (United States); Olivier Guyon, Julien Lozi, Subaru Telescope, NAOJ (United States); Barnaby R. M. Norris, The Univ. of Sydney (Australia); Andrew Skemer, Univ. of California, Santa Cruz (United States)
21 July 2022 • 16:10 - 16:30 | Room 520 b
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Kernel phase interferometry (KPI) is a data processing technique that treats data from a conventional telescope as if it were taken with an interferometric array. When the data is taken in space or with a high-quality AO correction, KPI makes it possible to search for companions and extended structures such as disks interior to the classical diffraction limit. KPI’s achievable contrast is often limited by complex systematics present in the calibrated kernel phases motivating the search for improved calibration strategies. We present an application of KPI to observations taken with the CHARIS IFS instrument mounted on Subaru/SCExAO. Taking advantage of the simultaneous multi-wavelength observations of CHARIS, we perform a spectral differential imaging (SDI) calibration of the kernel phases to demonstrate its scientific potential, limiting performance, and achievable contrast.
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Author(s): Mamadou N'Diaye, Observatoire de la Côte d'Azur (France); David Mary, Observatoire de la Côte d’Azur (France); Roxanne Ligi, Frantz Martinache, Nick Cvetojevic, Peter Chingaipe, Observatoire de la Côte d'Azur (France); Romain Laugier, KU Leuven (Belgium)
21 July 2022 • 16:30 - 16:50 | Room 520 b
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Kernel phase is a method to observe planetary companions by interpreting the formation of star images as the analytical result of an interferometric process. This analysis has so far been focused on a single monochromatic image, recently providing theoretical contrast detection limits down to 10^-4 at 200mas with JWST/NIRISS in the mid-infrared by using hypothesis testing theory. We propose to extend this formalism to IFS data cubes provided by ground-based telescopes with adaptive optics to enhance the detectability and characterization of planetary companions. Applications are investigated for ground-based exoplanet imagers (Subaru/SCExAO, VLT/SPHERE) and JWST.
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Author(s): Antoine Mérand, European Southern Observatory (Germany)
21 July 2022 • 16:50 - 17:10 | Room 520 b
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Despite image reconstruction becoming more widespread when interpreting OIFITS Data, model fitting in u,v space often remains the best way to interpret data, either because of the scarcity of the data, or because a quantitative measurement needs to be done. I present PMOIRED, a flexible code to visualise, manipulate and model OIFITS data using simple geometric models. The strength of PMOIRED resides in its capability to combine linearly various simple components to create complex scenes, while linking, constraining and adding priors to fitted parameters. The code also enables grid search to find global minima, as well as data resampling to better evaluate uncertainties. In addition to analytical functions, arbitrary radial profiles, azimuthal variations or sparse wavelet modelling of spectra are implemented. I will illustrate the presentation with archival data and new results.
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Author(s): Julien Drevon, Observatoire de la Côte d'Azur (France), European Southern Observatory (France); Pierre Cruzalèbes, Florentin Millour, Observatoire de la Côte d'Azur (France), CNRS (France); Claudia Paladini, Peter Scicluna, European Southern Observatory (Chile)
21 July 2022 • 17:10 - 17:30 | Room 520 b
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RHAPSODY (Reconstructing Hankel rAdial Profiles in centro-Symmetric Objects with Discrete rings for astrophYsics) is a tool built to reconstruct 1D chromatic intensity profiles using visibilities observed in LM and N Bands. It uses concentric discrete uniform rings and a Bayesian approach to provide a geometrical description of the scientific object. RHAPSODY is parallelized and provides normalized intensity profiles, image cubes and fitted flux ratios to each rings. It also plots for each wavelengths: a histogram of the residuals, a linear and logarithmic view of the reconstructed intensity profiles and visibilities and a global spectra of all the intensity profiles.
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Author(s): Fabien R. Baron, Elizabeth Lincoln, Georgia State Univ. (United States)
21 July 2022 • 17:30 - 17:50 | Room 520 b
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Speckle imaging is the most viable alternative to AO at visible wavelengths, but is hampered by suboptimal algorithms to reach its full potential. It appears that classic speckle interferometry algorithms have reached their performance limits, whereas full multi-frame blind deconvolution algorithms can reach higher contrasts but require inordinate amounts of computing power. We are presenting the first results obtained with both simulated and real data, using our new open source speckle imaging code based on a ADMM framework. In particular we are tackling object regularization and anisoplanetism, leading to significantly better images in shorter reconstruction times.
Session 10: Future of Interferometry
22 July 2022 • 09:00 - 11:30 | Room 520 b
Session Chair: Antoine Mérand, European Southern Observatory (Germany)
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In memoriam Matt Willson (Invited Paper)
Author(s): Antoine Mérand, European Southern Observatory (Germany); Stefan Kraus, Univ. of Exeter (United Kingdom); Fabien R. Baron, Georgia State Univ. (United States)
22 July 2022 • 09:00 - 09:20 | Room 520 b
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This session is to recall the career and contributions to our community of Matt Wilson, who tragically passed away prematurely.
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Author(s): Mercedes Filho, Univ. do Porto (Portugal)
22 July 2022 • 09:20 - 09:50 | Room 520 b
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The talk aims at presenting the VLTI Expertise Centre (VEC) network and its role within the broader community. The main goal of the VECs is to provide accessible resources in all phases of a VLTI proposal - from proposal and observation preparation to data analysis. It targets the broader observer community - from senior to early-stage researchers with little to no experience to the more experienced. The VECs also establish links between the observer VLTI community, VLTI stakeholders, the complementary radio/optical community, the private sector, as well as with the general public promoting synergies, collaborations and women in STEM.
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Author(s): Stefan Kraus, Daniel J. Mortimer, Sorabh Chhabra, Univ. of Exeter (United Kingdom); Michael J. Ireland, The Australian National Univ. (Australia); Frantz Martinache, Observatoire de la Côte d'Azur (France); Denis Defrère, Marc-Antoine Martinod, KU Leuven (Belgium); Tiphaine Lagadec, The Australian National Univ. (Australia); John D. Monnier, Univ. of Michigan (United States); Narsireddy Anugu, CHARA Array (United States); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Yi Lu, Isabelle Codron, Univ. of Exeter (United Kingdom)
22 July 2022 • 09:50 - 10:10 | Room 520 b
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We present science cases and instrument design considerations for a short-wavelength (Y/J/H-band), high spectral dispersion (R=25,000) instrument for the VLTI visitor focus. The BIFROST instrument will be part of the Asgard Suite of instruments and unlock powerful venues for studying accretion & mass-loss processes at the early/late stages of stellar evolution, for detecting accreting protoplanets around young stars, and for probing the spin-orbit alignment in directly-imaged planetary systems and multiple star systems. In conjunction with upcoming infrastructure improvements on the VLTI unit telescopes, the instrument could also enable off-axis spectroscopy of exoplanets in the 0.03-2” separation range, enabling high-SNR, high spectral resolution follow-up of exoplanets detected with ELT/JWST. We will give an update on the status of the project, outline our key technology choices, and discuss synergies with other instruments in the proposed Asgard Suite of instruments.
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Author(s): Xavier Haubois, Nicolas Schuhler, Pierre Bourget, European Southern Observatory (Chile); Julien Woillez, European Southern Observatory (Germany)
22 July 2022 • 10:10 - 10:30 | Room 520 b
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The STELLIM interferometer aims at providing fast and reliable imaging of the surface of cool evolved stars by combining the light of 13 telescopes in the visible. It is designed to take advantage of the existing VLTI infrastructure. STELLIM aims at producing stellar surface images at a high temporal cadence. It will deliver a complete spatio-temporal characterization of surface and circumstellar environment structures of bright evolved stars, which is pivotal to understanding the way those stars lose their mass in the interstellar environment and their evolution into supernovae. we will present the design and the steps we took to progress towards a STELLIM demonstrator.
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Author(s): Daniel J. Mortimer, Stefan Kraus, Univ. of Exeter (United Kingdom); John D. Monnier, Univ. of Michigan (United States); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Narsireddy Anugu, CHARA Array (United States); Sorabh Chhabra, Univ. of Exeter (United Kingdom)
22 July 2022 • 10:30 - 10:50 | Room 520 b
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BIFROST will be a short-wavelength (1.05 to 1.7 micrometer) beam combiner for the VLT Interferometer, combining both high spatial (λ/2B = 0.8mas) and spectral (up to R=25,000) resolution. It will be part of the Asgard Suite of visitor instruments. The broad wavelength range has implications for the choice of the beam combination scheme. Here, we present preliminary optical designs for both an all-in-one beam combination scheme and an integrated optics (IO) scheme with ABCD modulation. We discuss the implications on sensitivity, stability, and measurement precision, for instance with respect to baseline crosstalk. We also outline the implications of the beam combination scheme on the sequencing of the data recording, calibration and the data reduction strategy. Finally, we present our preliminary sensitivity estimates.
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Author(s): Massinissa Hadjara, Chinese Academy of Sciences South America Ctr. for Astronomy (CASSACA) (China), Univ. de Chile (Chile); Romain G. Petrov, Stéphane Lagarde, Univ. Côte d'Azur (France); Xinyang Chen, Shanghai Astronomical Observatory (China); Jinhua He, Chinese Academy of Sciences South America Ctr. for Astronomy (CASSACA) (China); Bruno Lopez, Florentin Millour, Anthony Meilland, Univ. Côte d'Azur (France); Slobdan Jankov, Astronomical Observatory Belgrade (Serbia); Alexandre Gallenne, Unidad Mixta Internacional Franco-Chilena de Astronomía (Chile); James H. Leftley, Univ. Côte d'Azur (France); Abdelkarim Boskri, Oukaimeden Observatory, Univ. Cadi Ayyad (Morocco); Juncheng Chen, Chinese Academy of Sciences South America Ctr. for Astronomy (CASSACA) (China), Univ. de Chile (Chile); Ernest Michael, Marcos Diaz, Univ. de Chile (Chile); Amelia Bayo, Univ. de Valparaíso (Chile); Miguel Piña, Univ. de Chile (Chile); Juan Colque, Univ. Autónoma de Chile (Chile); Congcong Zhang, Dan Zhou, Shanghai Astronomical Observatory (China); Fatmé Allouche, Univ. Côte d'Azur (France); Yinlei Hao, Zhejiang Univ. (China); Amokrane Berdja, Pontificia Univ. Católica de Chile (Chile); Felipe Besser, Las Campanas Observatory (Chile); Clémentine Marie Zélia Bechet, Andrés Guesalaga Meissner, Leonardo Vanzi, Pontificia Univ. Católica de Chile (Chile)
22 July 2022 • 10:50 - 11:10 | Room 520 b
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VERMILION is a VLTI visitor instrument project intended to extend the sensitivity and the spectral coverage of Optical Long Baseline Interferometry (OLBIn). It is based on a new concept of Fringe Tracker (VERMILION-FT) combined with a J band spectro-interferometer (VERMILION-J). The Fringe Tracker is the Adaptive Optics module specific to OLBIn that measures and corrects in real time the Optical Path Difference (OPD) perturbations introduced by the atmosphere and the interferometer, by providing a sensitivity gain of 2 to 3 magnitudes over all other state of the art fringe trackers. The J band spectro-interferometer will provide all interferometric measures as a function of wavelength. In addition to a possible synergy with MATISSE, VERMILION-J, by observing at high spectral resolution many strong lines in J (Paβ-γ, HeII, TiO and other metallic monoxides), will cover several scientific topics, e.g. Exoplanets, YSOs, Binaries, Active Hot + Evolved stars, Asteroseismology, and also AGNs.
12183-70
Author(s): Pierre-Marie Gori, Observatoire de la Côte d’Azur (France); Farrokh Vakili, Observatoire de la Côte d'Azur (France); William Guerin, Univ. Côte d’Azur (France), Institut de Physique de Nice, CNRS (France); Andrea Chiavassa, Observatoire de la Côte d’Azur (France); Jean-Pierre Rivet, Observatoire de la Côte d'Azur (France); Nolan K. Matthews, Mathilde Hugbart, Univ. Côte d’Azur (France); Robin Kaiser, Univ. Côte d'Azur (France); Olivier Lai, Observatoire de la Côte d’Azur (France)
22 July 2022 • 11:10 - 11:30 | Room 520 b
Session P1: Posters - Critical Subsystems
19 July 2022 • 18:00 - 20:00 | Room 516
12183-71
Author(s): GRAVITY+ Collaboration, Univ. Côte d'Azur (France); Florentin Millour, Univ Côte d'Azur (France); Philippe Bério, Univ. Côte d'Azur (France); Stéphane Lagarde, Sylvie Robbe-Dubois, Carole Gouvret, Olivier Lai, Fatmé Allouche, Christophe Bailet, Olivier Boebion, Marcel Carbillet, Univ. Côte d'Azur (France); Jean-Baptiste Lebouquin, Univ. Grenoble Alpes (France); Thibaut Paumard, Observatoire de Paris (France); Férréol Soulez, Univ. de Lyon (France); Julien Woillez, European Southern Observatory (Germany); Nikhil More, Frank Eisenhauer, Max-Planck-Institut für extraterrestrische Physik (Germany); Christian Straubmeier, Univ. zu Köln (Germany); Laura Kreidberg, Max-Planck-Institut für Astronomie (Germany); Paulo J. V. Garcia, Univ. do Porto (Portugal)
19 July 2022 • 18:00 - 20:00 | Room 516
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We present the testbench aimed at integrating the GRAVITY+ adaptive optics GPAO. It consists of two independent elements, one reproducing the Coudé focus of the telescope, including the telescope deformable mirror mount (with its surface facing down), and one reproducing the Coudé room opto-mechanical environment, including a downwards-propagating beam, and the telescope mechanical interfaces in order to fit in the new GPAO wavefront sensor. We will discuss the design of this bench and the solutions we adopted to keep the cost low, keep the design compact (allowing it to be fully contained in a 20 sqm clean room), and align the bench independently from the adaptive optics. We will also discuss the features we have set in this bench.
12183-72
Author(s): Colin Dandumont, Alexandra Mazzoli, Ctr. Spatial de Liège (Belgium); Romain Laugier, Azzurra Bigioli, Germain Garreau, KU Leuven (Belgium); Simon Gross, Macquarie Univ. (Australia); Michael J. Ireland, Harry-Dean Kenchington Goldsmith, The Australian National Univ. (Australia); Lucas Labadie, Univ. zu Köln (Germany); Victor Laborde, Ctr. Spatial de Liège (Belgium); Gert Raskin, KU Leuven (Belgium); Ahmed Sanny, KU Lueven (Belgium); Simon Verlinden, KU Leuven (Belgium); Jérôme Loicq, Liège Univ. (Belgium), Technische Univ. Delft (Netherlands); Denis Defrère, KU Leuven (Belgium)
19 July 2022 • 18:00 - 20:00 | Room 516
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Hi-5 is a possible L band high-contrast nulling interferometric instrument for the VLTI. The project aims to achieve sufficient dynamic range and angular resolution to directly image and characterize the snow line of young extra-solar planetary systems. The outputs of the integrated optic beam-combiner are spectrally dispersed with a resolving power of R = 20, 400 or 2000 thanks to a GRISM. The technical requirements and optical design of the Hi5 spectrometer are presented and discussed.
12183-73
Author(s): Azzurra Bigioli, KU Leuven (Belgium); Roberto Abuter, European Southern Observatory (Germany); Benjamin Courtney-Barrer, European Southern Observatory (Chile); Denis Defrère, KU Leuven (Belgium); Frank Eisenhauer, Max-Planck-Institut für extraterrestrische Physik (Germany); Romain Laugier, Salman Muhammad, Gert Raskin, KU Leuven (Belgium); Nicolas Schuhler, Julien Woillez, European Southern Observatory (Germany)
19 July 2022 • 18:00 - 20:00 | Room 516
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The vibrations affecting the telescopes largely contribute to the optical path length error in interferometry. At the VLTI-UT, telescope vibrations are measured and compensated with MANHATTAN-II*. Its upgrade, necessary for bringing down the current OPDrms of ~200 nm to 100 nm, must be supported by an assessment of the intrinsic self-noise of the vibration’s measurement chain. We find that the one-mirror noise is of the order of 2 µg/Hz0.5 in the amplifier bandwidth 1 Hz – 25 kHz. Accounting for all sensors, this corresponds to an overall OPDrms of 143 nm, which is insufficient to reach the ultimate limit of the atmospheric piston. Some hints for improvement are proposed.
12183-74
Author(s): Germain Garreau, Azzurra Bigioli, KU Leuven (Belgium); Colin Dandumont, Ctr. Spatial de Liège (Belgium); Harry-Dean Kenchington Goldsmith, The Australian National Univ. (Australia); Simon Gross, Macquarie Univ. (Australia); Michael J. Ireland, The Australian National Univ. (Australia); Lucas Labadie, Univ. zu Köln (Germany); Romain Laugier, KU Leuven (Belgium); Stephen Madden, The Australian National Univ. (Australia); Guillermo Martin, Institut de Planétologie et d’Astrophysique de Grenoble (France); Alexandra Mazzoli, Ctr. Spatial de Liège (Belgium); Johan Morren, Gert Raskin, KU Leuven (Belgium); Hancheng Shao, Kunlun Yan, The Australian National Univ. (Australia); Denis Defrère, KU Leuven (Belgium)
19 July 2022 • 18:00 - 20:00 | Room 516
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Hi-5, a possible visitor instrument for the VLTI, is an ambitious project aiming at detecting young giant exoplanets close to the snow line using long baseline and nulling interferometry in the L spectral band with integrated optics. This work introduces the design of the warm optics and free-space injection system into the photonic beam combiner. Particular attention is devoted to the alignment tolerances and symmetry between the input beams, properties tested using a dedicated optical bench simulating the four VLTI beams.
12183-75
Author(s): Roberto Abuter, European Southern Observatory (Germany); Roderick Dembet, Observatoire de Paris (France); Robert Frahm, European Southern Observatory (Germany); Sylvestre Lacour, Observatoire de Paris (France); Julien Woillez, European Southern Observatory (Germany)
19 July 2022 • 18:00 - 20:00 | Room 516
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The GRAVITY fast fringe tracker project aims at improving the performance of the GRAVITY instrument fringe tracker by restructuring and deploying its control loop on a multi-core CPU under Linux including new pixel acquisition and real time adaptations. This new implementation reduces the pure delay of the control loop by a factor of ~10 to ~100 µsec and , as a consequence, the bandwidth of the loop is substantially improved. This presentation will give a detailed overview of the restructuring and modifications done to the system. Finally, based on early results from test runs on site, improvements in bandwidth and residual optical path delay will be quantified.
12183-76
Author(s): Romain Laugier, Denis Defrère, KU Leuven (Belgium); Alexis Matter, Observatoire de la Côte d'Azur (France); Benjamin Courtney-Barrer, European Southern Observatory (Chile); Felix Dannert, ETH Zurich (Switzerland); Julien Woillez, European Southern Observatory (Germany); Azzurra Bigioli, KU Leuven (Belgium); Olivier Absil, Liège Univ. (Belgium); Colin Dandumont, STAR Institute, Liège Univ. (Belgium)
19 July 2022 • 18:00 - 20:00 | Room 516
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The SCIFY project aims to design, build and commission Hi-5, the first nulling beam-combiner of the VLTI, optimized for the detection and characterization of young giant exoplanets near the snowline, with spectroscopy up to R=2000 in the L' band. It will make use of advanced four-beam nulling combination schemes, like double-Bracewell and kernel-nulling implemented in a single-mode photonic device to produce self-calibrating nulled outputs. In order to estimate the practical performance of these different configurations in a regime where both instrumental errors and background noise are significant, we have developed the end-to-end simulator SCIFYsim. We use statistical tests based on likelihood ratios to evaluate detection limits that leverage all wavelength channels and showcase some examples and the technical limitations.
12183-77
Author(s): Giovanni Bonanno, Giuseppe Romeo, Lorenzo Paoletti, Luca Zampieri, INAF (Italy); Giampiero Naletto, Univ. degli Studi di Padova (Italy); Pietro Bruno, Alessandro Grillo, Giovanni Occhipinti, Maria Cristina Timpanaro, Giovanni Pareschi, Salvatore Scuderi, Gino Tosti, INAF (Italy)
19 July 2022 • 18:00 - 20:00 | Room 516
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The ASTRI Mini-Array is an International collaboration led by the Italian National Institute for Astrophysics (INAF), that is constructing and operating nine telescopes to perform Cherenkov and optical stellar intensity interferometry (SII) observations. At the focal plane of these telescopes we are planning to install a stellar intensity interferometry instrument. Here we present the final selected design, based on Silicon Photomultipliers (SiPMs) detectors matching the telescope point spread function and a dedicated front end electronics.
12183-78
Author(s): Daniel J. Mortimer, Univ. of Exeter (United Kingdom), Univ. of Cambridge (United Kingdom); David F. Buscher, Univ. of Cambridge (United Kingdom); Michelle J. Creech-Eakman, Magdalena Ridge Observatory, New Mexico Institute of Mining and Technology (United States); Christopher A. Haniff, Univ. of Cambridge (United Kingdom); Christopher Salcido, Magdalena Ridge Observatory, New Mexico Institute of Mining and Technology (United States); Eugene Seneta, Xiaowei Sun, John Young, Univ. of Cambridge (United Kingdom)
19 July 2022 • 18:00 - 20:00 | Room 516
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FOURIER is the first-generation science beam combiner for the MROI. It is a three-way, J, H and K band image plane combiner. The FOURIER design emphasises low visibility losses and high optical throughput and is designed around a low-noise SAPHIRA detector. Based on laboratory measurements of its throughput and visibility losses, FOURIER is expected to reach limiting magnitudes of 12.3, 13.2 and 11.7 in the J, H and K bands, respectively, within 5 minutes of incoherent integration assuming optimum seeing and a detector read noise of 0.3 electrons. As FOURIER observes as red as the K band, the detector and most of its optics are placed within a liquid nitrogen cryostat. Here we present the design of FOURIER’s cryostat, as well as laboratory tests of the instrument’s cryogenic performance. We also show refined room temperature characterisation of the optics. Finally, we discuss the path forward from the current status of the instrument to first fringes.
12183-79
Author(s): Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico); Rebeca García-López, Univ. College Dublin (Ireland); Salvador Cuevas, Univ. Nacional Autónoma de México (Mexico)
19 July 2022 • 18:00 - 20:00 | Room 516
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Since its deployment at the Very Large Telescope Interferometer, GRAVITY has consolidated as one of the most important interferometers. Given its prolific results, the European Southern Observatory and the GRAVITY consortium decided to expand the capabilities of the instrument to make it more accessible to the global astronomical community and to open new research windows. The upgrade of the instrument is called GRAVITY+ . It will be implemented in a time-frame of 5 years and it will provide the following scientific capabilities: a new laser Adaptive Optics system and a new fringe tracker capabilities to improve the sky coverage for interferometric observations. We present a complementary development for GRAVITY+ to improve the spectral capabilities of the instrument. Here, we describe the design of a new Ge prism to be installed in the filter wheel of GRAVITY+ to achieve a spectral resolution of R~15000. We describe our grism design and the scientific drivers behind this development.
12183-80
Author(s): John S. Young, Christopher A. Haniff, David F. Buscher, Eugene Seneta, Xiaowei Sun, James J. D. Luis, Martin Fisher, Donald Wilson, Univ. of Cambridge (United Kingdom); Michelle J. Creech-Eakman, New Mexico Institute of Mining and Technology (United States); Christopher Salcido, Allen Farris, Robert Collins, New Mexico Institute of Mining and Technology (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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The fast tip-tilt (FTT) correction system for the Magdalena Ridge Observatory Interferometer (MROI) was first tested on sky in November 2018. In preparation for the deployment of the second MROI Unit Telescope (UT) in late summer 2022, more extensive testing of the first UT and FTT system is being carried out. We report measurements of the FTT correction performance over a range of seeing conditions, and discuss strategies for choosing the optimal detector readout mode, frame rate and servo parameters for the prevailing seeing as determined from measurements by the FTT system itself.
12183-81
Author(s): Christopher D. Farrington, E. Robert Ligon, Theo A. ten Brummelaar, Douglas R. Gies, Gail Schaefer, Nicholas Scott, Narsireddy Anugu, Matthew D. Anderson, Rainer Koehler, Nils Turner, Steven Golden, Craig Woods, CHARA Array (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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The CHARA Michelson Array Pathfinder project offers many unique challenges of design and implementation to create the longest baselines for optical interferometry. In order to establish these long baselines, we must consider how to safely and efficiently move a 1-m telescope and enclosure from one site to another within the limitations of the current observatory's terrain. The only "off-the-shelf" solution on the market would be too cumbersome to adapt to our needs, and so we are left with a design challenge. Herein, we shall describe the difficulties and possible solutions for the enclosure and transport of the entire telescope structure around the Mount Wilson Observatory grounds.
Session P2: Posters - Observing Techniques
19 July 2022 • 18:00 - 20:00 | Room 516
12183-82
Author(s): François B. Hénault, Institut de Planétologie et d’Astrophysique de Grenoble (France)
19 July 2022 • 18:00 - 20:00 | Room 516
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Field of View (FoV) and contrast limitations of stellar interferometers have been the scope of numerous publications for more than thirty years. Recently, this topic regained some interest since long-baseline terrestrial interferometers (not to be mistaken with space borne nulling interferometers) are envisioned for detecting and characterizing extra-solar planets orbiting in the habitable zone of their parent star. This goal supposes to achieving sufficient contrast ratio in the high angular frequency domain, thus on the whole interferometer FoV. In this paper are reviewed some of the contrast and FoV limiting factors, including spectral bandwidth, telescope image quality, optical conjugation of the telescopes entrance pupils, Signal-to-Noise Ratio, deviations with respect to “the golden rule of imaging interferometers” and the influence of anamorphosing optics. Finally, a tentative classification of all these factors is provided
12183-83
Author(s): Colin Dandumont, Ctr. Spatial de Liège (Belgium); Romain Laugier, KU Leuven (Belgium); Alexandre Emsenhuber, Ludwig-Maximilians-Univ. München (Germany); Jonathan Gagne, Univ. de Montréal (Canada); Olivier Absil, Liège Univ. (Belgium); Azzurra Bigioli, Germain Garreau, KU Leuven (Belgium); Michael J. Ireland, The Australian National Univ. (Australia); Simon Verlinden, KU Leuven (Belgium); Jérôme Loicq, Liège Univ. (Belgium), Technische Univ. Delft (Netherlands); Denis Defrère, KU Leuven (Belgium)
19 July 2022 • 18:00 - 20:00 | Room 516
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Hi-5 is a possible L’ band high-contrast nulling interferometric instrument for the VLTI. The project aims to achieve sufficient dynamic range and angular resolution to directly image and characterize the snow line of young extra-solar planetary systems. We present our simulations of potential detections and the potential target list for the instrument. The New Generation Planetary Population Synthesis (NGPPS) and a statistical model based on gravitational instability (hot-start models) are used to derive the detection yield.
12183-84
Author(s): Benjamin Courtney-Barrer, European Southern Observatory (Chile); Julien Woillez, European Southern Observatory (Germany); Romain Laugier, Azzurra Bigioli, KU Leuven (Belgium); Nicolas Schuhler, Patricia Guajardo, Vicente Lizana, Natalie Behara, European Southern Observatory (Chile); Frank Eisenhauer, Max-Planck-Institut für extraterrestrische Physik (Germany); Michael J. Ireland, The Australian National Univ. (Australia); Xavier Haubois, European Southern Observatory (Chile); Denis Defrère, KU Leuven (Belgium)
19 July 2022 • 18:00 - 20:00 | Room 516
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With the push for higher sensitivity and contrast at the VLTI, comes a fundamental requirement for improved control of the optical path differences (OPD) between interfering beams. For this work we look to cross correlate various data sources including the Gravity Fringe Tracker, accelerometers, metrology systems, adaptive optics and telescope logs to understand current limitations for the OPD in the VLTI – including the impact of single mode waveguide coupling, and potentially understand why the measured OPD fundamentally does not follow the expected filtered Kolmogorov behavior. Understanding these will be critical for pushing the sensitivity and contrast limitations of the VLTI.
12183-85
Author(s): Chafi Jamal, Univ. Cadi Ayyad (Morocco); Youssef El Azhari, Univ. Cadi Ayyad (Morocco), CRMEF, Marrakech Safi (Morocco), Oukaimeden Observatory, Univ. Cadi Ayyad (Morocco); Ossama Azagrouze, Univ. Cadi Ayyad (Morocco), CRMEF, Marrakech Safi (Morocco), Oukaimeden Observatory, Univ. Cadi Ayyad (Morocco); Abdelhadi Jabiri, Univ. Cadi Ayyad (Morocco); Abdelfettah Habib, Univ. Cadi Ayyed (Morocco), CRMEF (Morocco); Benkhaldoun Zouhair, Univ. Cadi Ayyad (Morocco), Oukaimeden Observatory, Univ. Cadi Ayyad (Morocco)
19 July 2022 • 18:00 - 20:00 | Room 516
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In this work, the method of apodization by interferometry of a rectangular or circular aperture using homothety. We discuss the principle of the method and we present as a first step the proposed experimental setup. We then present the results of the optimization of the free parameters of the system allowing us to concentrate the maximum of the light energy coming from the star in the central lobe of diffraction. This allows us to dimension the system, taking into account the practical constraints. Simulation results will be presented for the case of circular and rectangular geometries. We also present the first experime
12183-86
Author(s): Shrishmoy Ray, Sasha Hinkley, Univ. of Exeter (United Kingdom); Stephanie Sallum, Univ. of California, Irvine (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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JWST will transform our ability to characterise directly imaged exoplanets. As a part of the ERS Program 1386, in addition to imaging and spectroscopy, we will test JWST’s NIRISS/AMI mode with the observations of HIP 65426 b, imaging within the diffraction limit, for the first time on a space telescope. Results obtained using synthetic NIRISS/AMI contrasts combined with evolutionary models, relying on Beta Pictoris and TW Hydrae moving groups and the Taurus association, indicate that for some targets, companions at separations <10 AU from the star with masses <10 Mjup can be imaged using with a confidence of >80%. A series of such successful detections with future surveys would be a testament to the abundance of exoplanets being formed with core accretion, similar to our Solar system’s history. These potential discoveries will hence convey that Solar System analogues are common and inform our understanding of the conditions that may be suitable for habitability on exoplanets.
12183-87
Author(s): Ellyn K. Baines, Henrique R. Schmitt, U.S. Naval Research Lab. (United States); J. Thomas Armstrong, Computational Physics, Inc. (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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The Navy Precision Optical Interferometer (NPOI) has been in operation since 1996, building a substantial data archive. This provided the opportunity to determine how many data points are needed for a single star's angular diameter fit to become stable as more data points were included. In an iterative process, we calculated the diameters for an ever-increasing number of data points for several dozen stars. We found that at approximately 1000 data points, the scatter in the diameter fits fell below 1%. Assuming a 3-telescope triangle and using 15 channels across a range of wavelengths, 1000 data points equates to 22 to 25 bracketed observations, which can usually be accomplished in 2 to 3 nights. This will be a useful rule-of-thumb when planning observations and gathering data on single, symmetrical stars.
12183-88
Author(s): Boris S. Safonov, Sternberg Astronomical Institute, M. V. Lomonosov Moscow State Univ. (Russian Federation); Maxwell Millar-Blanchaer, Rebecca Zhang, Univ. of California, Santa Barbara (United States); Barnaby R. M. Norris, The Univ. of Sydney (Australia); Olivier Guyon, National Astronomical Observatory of Japan (United States), The Univ. of Arizona (United States), Astrobiology Ctr., National Institutes of Natural Sciences (Japan); Julien Lozi, National Astronomical Observatory of Japan (United States); Stephanie Sallum, Univ. of California, Irvine (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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The differential polarization visibilities R_Q and R_U of an object are the ratios of its visibilities corresponding to orthogonal polarizations, the interferometric analogs to Stokes Q and U intensity images. The measurement of differential polarization visibilitites can be used for constraining inner parts of circumstellar envelopes of young or evolved stars at diffraction limited resolution of the feeding telescope. Here we demonstate the estimation of both amplitude and phase of R_Q and R_U from data obtained using SCExAO VAMPIRES through the full pupil of the 8-m Subaru telescope using the Differential Speckle Polarimetry technique. The correction for biases arising due to instrumental polarization effects is discussed. The uncertainty of R measurement with VAMPIRES can be explained by the photon noise and readout noise. For m_R=8 star a series consisting of 19200 frames at exposure of 10~ms gives random noise of 5e-4 at frequency of D/lambda, where D is the aperture diameter.
12183-89
Author(s): Mackenzie R. Lach, Stephanie Sallum, Univ. of California, Irvine (United States); Andrew Skemer, Univ. of California, Santa Cruz (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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Aperture masking has the potential to enhance spatial resolution capabilities when imaging high-contrast sources with small angular size. The Santa Cruz Array of Lenslets for Exoplanet Spectroscopy (SCALES) instrument, currently under development, is an integral field spectrograph that will enable W. M. Keck Observatory to carry out high-contrast direct imaging of exoplanets between 2 and 5 microns. We explore the potential benefit of aperture masking to SCALES by testing the contrast achievable with several mask designs. We model the injection and recovery of various planet and extended disk signals in the L-band using the scalessim software package.
Session P3: Posters - Technologies
19 July 2022 • 18:00 - 20:00 | Room 516
12183-90
Author(s): Philippe Feautrier, Jean-Luc Gach, First Light Imaging S.A.S. (France)
19 July 2022 • 18:00 - 20:00 | Room 516
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We present here the latest results obtained with the C-RED One camera developed by First Light Imaging for fast ultra-low noise infrared applications. This camera uses the Leonardo Saphira e-APD 320x256 infrared sensor in an autonomous cryogenic environment. Some recent improvements were made to the camera. Limited to 1.75 micron wavelength cut-off with proper cold filters, looking a blackbody at room temperature and f/4 beam aperture, we now measure total noise down to 0.18 e at gain 50 in CDS mode 1720 FPS. The total camera background of 10 e/s was now achieved with a factor 5 of background reduction. Image bias oscillations were removed. Focal plane detector vibrations transmitted by the pulse tube were damped and measured down to 0.1 microns RMS. A future plan is also to integrate active damping reducing vibration level by another factor of 10. Future developments using the new large format Leonardo 2Kx2K SWIR APD array will be also shown.
12183-91
Author(s): Andrei Nomerotski, Brookhaven National Lab. (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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Observations using interferometers provide sensitivity to features of images on angular scales much smaller than any single telescope, on the order of Delta theta ~ lambda/b where b is the interferometric baseline. Present-day optical interferometers are essentially classical, interfering single photons with themselves. However, there is a new wave of interest in interferometry using multiple photons, whose mechanisms are inherently quantum mechanical, which offer the prospects increased baselines and finer resolutions among other advantages. We will discuss recent ideas for quantum-assisted interferometry using the resource of entangled pairs, and specifically a two-photon amplitude technique aimed at improved precision in dynamic astrometry.
12183-92
Author(s): Wyatt E. Clark, Lowell Observatory (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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The implementation of a Raspberry Pi-based control system for precision optomechanical alignment at the Navy Precision Optical Interferometer is presented. The Interferometer is presently undergoing a period of mechanical upgrades to many of the critical systems including its six Periscopes. A new controller is necessary to actuate the multitude of gimbaled mirrors, linear stages, and mirror-cell locks housed in a single Periscope. A prototype controller is evaluated on its effectiveness to precisely control the mechanical components, ability to interface with the network for remote operation and cost analysis for all six Periscopes.
12183-93
Author(s): Abani Shankar Nayak, Leibniz-Institut für Astrophysik Potsdam (Germany); Lucas Labadie, Tarun K. Sharma, Univ. zu Köln (Germany); Simone Piacentini, Politecnico di Milano (Italy), CNR-Istituto di Fotonica e Nanotecnologie (Italy); Giacomo Corrielli, Roberto Osellame, CNR-Istituto di Fotonica e Nanotecnologie (Italy), Politecnico di Milano (Italy); Ettore Pedretti, STFC Rutherford Appleton Lab., UK Research and Innovation (United Kingdom); Aline N. Dinkelaker, Kalaga V. Madhav, Martin M. Roth, Leibniz-Institut für Astrophysik Potsdam (Germany)
19 July 2022 • 18:00 - 20:00 | Room 516
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We recently performed tests of the discrete beam combiner (DBC) through an on-sky experiment using a 4-input pupil remappers-based integrated optics device. Here, we report on the lessons learned, as well as visibilities and closure phase results for stellar targets such as Vega and Altair. Through complementary simulations, we analyze how the residual phase errors, input power imbalance at the waveguides, and slow environmental changes affect the performance of the DBC. This is an important aspect to improve future on-sky calibration strategies for this type of beam combiner, in particular when combining a large number of apertures.
12183-94
Author(s): Roberto Abuter, Nicolas Benes, European Southern Observatory (Germany)
19 July 2022 • 18:00 - 20:00 | Room 516
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The VLTI vibration control system gather , in real time, acceleration data from 8 probes distributed over the telescope and calculates corresponding piston corrections to be send to the specific delay lines involved in the tracking at 4KHz. This work will present a new, GNU radio framework based, implementation of the system aiming at improving its performance , scalability and maintainability. It also shows how the various native features of GNU radio framework can be combined and used to achieve those goals. Finally, using test-bench data, a quantitative analysis and comparison will be made between the two systems.
Session P4: Posters - Data Processing Analysis Access and Discovery
19 July 2022 • 18:00 - 20:00 | Room 516
12183-95
Author(s): Narsireddy Anugu, CHARA Array, Georgia State Univ. (United States); Jacques Kluska, KU Leuven (Belgium); Gail Schaefer, CHARA Array (United States); John D. Monnier, Univ. of Michigan (United States); Stefan Kraus, Univ. of Exeter (United Kingdom); Jean-Baptiste Le Bouquin, Institut de Planétologie et d’Astrophysique de Grenoble (France)
19 July 2022 • 18:00 - 20:00 | Room 516
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With six telescopes and the world's largest baseline lengths ranging from 30-300 meters, the CHARA array offers a wide range of opportunities for optical interferometric imaging with an angular resolution λ/2B ~ 0.5 mas at H-band wavelengths. We use CHARA to study morphological complexity around evolved circumbinary stars by exploiting the recently installed highly sensitive six telescope beam combiner instruments MIRC-X (J+H band) and MYSTIC (K-band). Our follow-up observations of six post-AGB binaries give us unprecedented insights into these complex objects. We reveal binary astrometric positions, circumbinary disks, and binary-disk interactions resulting in disk misalignments. We believe post-AGB binaries are ideal laboratories to study binary-disk interactions where similar observational opportunities are rare in young stellar objects. We here report the observations and science results.
12183-96
Author(s): Henrique R. Schmitt, Ellyn K. Baines, U.S. Naval Research Lab. (United States); Tom Armstrong, Computational Physics, Inc. (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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We used the Navy Precision Optical Interferometer to observe cool giant stars in the wavelength range 550-850nm, which includes several TiO bands. Given that our observations use relatively broad channels, with spectral resolution R~30, we use stellar models to disentangle the continuum and absorption line contribution to the observed visibilities. These observations are used to determine and compare the diameters of these stars in the continuum and in the TiO bands, and to determine how this ratio changes as a function of stellar properties.
12183-97
Author(s): Adittya Pal, National Institute of Science Education and Research (India); Sorabh Chhabra, Anamparambu N. Ramaprakash, Inter-Univ. Ctr. for Astronomy and Astrophysics (India)
19 July 2022 • 18:00 - 20:00 | Room 516
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Two new versions of the classic hybrid input-output algorithm (HIOA of Fienup) are proposed for phase retrieval. The first combination is continuous HIOA (cHIOA) with HIOA, while the second is relaxed averaged alternating reflection algorithm (RAARA) with HIOA. These combinations of proposed algorithms with Fienup's version of HIOA are called cHIOA/HIOA and RAARA/HIOA, respectively. The proposed algorithms outperform a combined version of the error reduction algorithm (ERA) and HIOA, optimized earlier at retrieving the input image and the phase values, given only the amplitude in the frequency domain against loose support in the space domain. The performance of the proposed iterative phase retrieval algorithms is compared in terms of sum squared error (SSE). Numerical simulations of the phase retrieval show considerable improvement in SSE values of the reconstructed image and comparatively minor reconstructed phase errors against an optimized version of ER/HIOA.
12183-98
Author(s): Youssef Errazzouki, Univ. Cadi Ayyad (Morocco); Abdelfettah Hbib, Ctr. Régional des Métiers de l’Education et de la Formation (Morocco); Mohammed Sabil, National School of Applied Sciences (Morocco); Abdelhadi Jabiri, Zouhair Benkhaldoun, Univ. Cadi Ayyad (Morocco)
19 July 2022 • 18:00 - 20:00 | Room 516
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The evaluation of atmospheric turbulence has been ongoing concern of astrophysicists, in this regard we will present and discuss a method of determining atmospheric turbulence profiles parameters, based on the analysis of stellar scintillation produced by the passage of the light through the turbulence layers by calculating the autocorrelation of scintillation images, We start by simulating a phase screen using the FFT method ”Fast Fourier Transform” which marks a good agreement when we compare his structure function with that of Kolmogorov. After having a good phase screen we calculate his simulated power spectrum function, this last reflects faithfully the theoretical one and shows also a good correspondence. Afterwards we make a minimization of this functions in order to characterize the atmospheric parameters using an optimization program called Active-Set. Our work is mainly focused on the vertical profile of refractive-index structure constant
12183-99
Author(s): Stephanie Sallum, Univ. of California, Irvine (United States); Shrishmoy Ray, Sasha Hinkley, Univ. of Exeter (United Kingdom)
19 July 2022 • 18:00 - 20:00 | Room 516
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The aperture masking interferometry (AMI) mode on JWST’s Near Infrared Imager and Slitless Spectrograph (NIRISS) will provide sub-diffraction-limited angular resolution with unprecedented sensitivity. Through the Director’s Discretionary Early Release Science (ERS) Program 1386, we will be benchmarking NIRISS AMI performance using observations of the known exoplanetary system HIP 65426. We will also be releasing an independent, python-based data reduction pipeline that extracts observables in the Fourier domain. Here we present pipeline preparations for ERS 1386. We describe the data processing steps and demonstrate their preliminary performance using simulated observations. Based on these simulated data, we also present synthetic contrast curves for NIRISS, and its expected sensitivity to additional companions in the HIP 65426 system.
Session P5: Posters - Future of Interferometry
19 July 2022 • 18:00 - 20:00 | Room 516
12183-100
Author(s): E. Robert Ligon, Matthew D. Anderson, Narsireddy Anugu, Christopher D. Farrington, CHARA Array (United States); Douglas R. Gies, Georgia State Univ. (United States); Steven Golden, CHARA Array (United States); Ludovic Grossard, XLIM (France); Rainer Koehler, CHARA Array (United States); Julie Magri, XLIM (France), Univ. de Limoges (France); Stephen Ridgeway, NoirLab (United States); Gail Schaefer, Laszlo Sturmann, Theo A. ten Brummelaar, Nils Turner, Craig Woods, CHARA Array (United States)
19 July 2022 • 18:00 - 20:00 | Room 516
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Much research has been done to show the possibilities of using long transport fibers in optical interferometry. The CHARA Michelson Array Pathfinder will extend the spatial coverage of the CHARA Array by adding a mobile 1-meter telescope connected by optical fibers. The pathfinder will operate in H-band and will explore baselines up to approximately 1 km, giving an angular resolution of 0.2 mas. The new telescope will be placed at short baselines to image the surfaces of large stars and at long baselines to resolve small stars. Here we describe our design for the mobile telescope system.
Conference Chair
European Southern Observatory (Chile)
Conference Chair
Univ. of California, Irvine (United States)
Conference Chair
Univ. Nacional Autónoma de México (Mexico)
Program Committee
Georgia State Univ. (United States)
Program Committee
Institut de Planétologie et d’Astrophysique de Grenoble (France)
Program Committee
New Mexico Institute of Mining and Technology (United States)
Program Committee
Takayuki Kotani
National Astronomical Observatory of Japan (Japan)
Program Committee
European Southern Observatory (Chile)
Program Committee
Univ. Católica del Norte (Chile)
Program Committee
Univ. zu Köln (Germany)
Program Committee
Sebastian F. Hönig
Univ. of Southampton (United Kingdom)
Program Committee
Observatoire de la Côte d'Azur (France)
Program Committee
Rachael Marie Roettenbacher
Yale Univ. (United States)
Program Committee
NASA Goddard Space Flight Ctr. (United States)
Program Committee
Gail H. Schaefer
CHARA (United States)
Program Committee
The Univ. of Sydney (Australia)