In progress – view active session
Conference 13095
Optical and Infrared Interferometry and Imaging IX
17 - 21 June 2024 | Room G416/417, North - 4F
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Monday Plenary
17 June 2024 • 08:20 - 10:00 Japan Standard Time | National Convention Hall, 1F
View Full Details: spie.org/AS/monday-plenary
13173-500
Moving TMT forward: Japan’s contributions and transformative approach toward community engagement
(Plenary Presentation)
17 June 2024 • 08:30 - 09:15 Japan Standard Time | National Convention Hall, 1F
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The Thirty Meter Telescope International Observatory (TIO) is an ambitious international scientific endeavor. In Part 1, we highlight Japan’s contributions toward technical advancements. Building upon the scientific and engineering success of the Subaru Telescope and ALMA, Japan leads in developing the telescope structure, primary mirror production, and cutting-edge science instruments. Part 2 delves into TIO’s transformative shift toward community engagement. At TIO, we believe in community model of astronomy that upholds the values of inclusion, respect, and community stewardship. We are committed to listening to, learning from, and working together with Hawaiʻi commuities to build a brighter future for all.
13173-501
From dark skies to bright futures: the evolution of astronomy in Africa and the hosting of the historic International Astronomical Union General Assembly 2024
(Plenary Presentation)
17 June 2024 • 09:15 - 10:00 Japan Standard Time | National Convention Hall, 1F
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Africa's unique dark skies offer vast potential for astronomy, which has significantly advanced over the last two decades through substantial investment in infrastructure and human capital. The African Astronomical Society (AfAS), relaunched in 2019, plays a crucial role in this ascent, enhancing the network of astronomers across the continent, fostering research collaborations, and advising on policy. Noteworthy achievements for Astronomy in Africa include securing a bid to host the mid-frequency component of the Square Kilometre Array (SKA) telescope, hosting the first International Astronomical Union (IAU) General Assembly in Africa in August 2024, and being home to the IAU Office of Astronomy for Development (OAD) since 2011. This talk highlights these milestones, illustrating the community's commitment to developing astronomy on the continent and utilising astronomy as a tool to address developmental challenges.
Session 1:
Current and Planned Facilities I
17 June 2024 • 10:30 - 12:00 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Stephanie E. Sallum, Univ. of California, Irvine (United States)
13095-1
Recent technical and scientific highlights from the CHARA Array
(Invited Paper)
On demand | Presented live 17 June 2024
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The Center for High Angular Resolution Astronomy (CHARA) Array is a six-element interferometer with baselines ranging from 31 to 331 m. The Array has had many upgrades in recent years including new beam combiners: MYSTIC is a 6T combiner for K-band; SPICA is a 6T combiner for the visible R-band; and Silmaril is a 3T combiner for high sensitivity in H- and K-bands. A seventh, mobile telescope now exists for use with fiber optics for beam transport. Observing time is available to the community through a program funded by NSF. The observing programs are solicited and peer-reviewed by NSF's NOIRLab.
13095-2
On demand | Presented live 17 June 2024
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SPICA (Stellar Parameters and Images with a Cophased Array) is a 6-telescope (6T) visible instrument for the
CHARA Array (Center for High Angular Resolution in Astronomy) at Mount Wilson Observatory. It uses single
mode fibers for feeding the interferometric spectrograph, which offers three different spectral resolutions: R=140,
R=4000, and R=14000. CHARA/SPICA has been mainly designed for large programs (surveys) in the domain
of stellar fundamental parameters but also permits fast imaging thanks to the 15 baselines and the large number
of spectral channels (60 in low resolution mode). SPICA is made of the visible instrument SPICA-VIS and of a
new H-band, 6T, ABCD combiner performing group delay and phase delay tracking. In this paper, we present
the first light results of SPICA
Show Abstract +
The Center for High Angular Resolution Astronomy (CHARA) Array currently consists of 6 telescopes at fixed positions, connected by vacuum pipes to the delay lines. The CHARA Michelson Array Pathfinder (CMAP) project includes two major components: 1) a mobile telescope that can be placed at a number of locations, and 2) a fiber optic relay system to transport light to the beam combining facility. The telescope will be equipped with a custom-built instrument bench with adaptive optics and fiber injection. The light will be transported by optical fibers to the existing CHARA delay lines. In this contribution, we present the progress on the various subsystems needed to integrate the new telescope and beam transport method into the existing CHARA environment. We will also describe our efforts to find internal fringes with the new fibers.
Show Abstract +
Silmaril is a new 3-telescope beam combiner at the CHARA Array. In this presentation, we present the current design of the instrument, its on-sky measured and theoretical best performance, and its future development.
Its design is specifically made to push for sensitivity. It combines 3 beams of the CHARA Array, allowing closure phase measurement but limiting the loss in sensitivity. It limits the number of optical elements to the minimum needed for combining the 3 beams. The use of a CRED ONE camera allows for sub-electron readout noise, which means that our sensitivity is thermal background limited. Long focal-length cylindrical mirrors limit the amount of thermal background with the use of an f/20 cold stop in front of the camera. We use a low spectral resolution prism to allow fringe tracking without compromising the sensitivity of the instrument. Thanks to an ingenious edge filter design, we can observe both H- and K-band simultaneously, with a low thermal background on the H-band side of the detector. In the future, we intend to extend the instrument with a second set of 3 beams and add a Narcissus mirror to lower the thermal background and improve the sensitivity even more.
Session 2:
Current and Planned Facilities II
17 June 2024 • 13:30 - 15:10 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Jens Kammerer, European Southern Observatory (Germany)
Show Abstract +
The Large Binocular Telescope Interferometer (LBTI) is a strategic instrument which combines the two 8.4m apertures of the LBT for sensitive, high-angular-resolution imaging and interferometric observations in the thermal infrared. Through its observing modes utilizing adaptive optics, Fizeau imaging, and nulling interferometry, the LBTI is in many respects the first ELT; it serves as a pioneer for upcoming ELTs in terms of both science and instrumentation. LBTI has completed a large survey for habitable-zone dust around main sequence stars, exploiting its angular resolution to obtain 100x better sensitivity than space-based photometric observations. Recently we have emphasized Fizeau interferometry, supporting high-contrast and precision-astrometric observations. We obtained the first extragalactic and N band observations in this mode, demonstrating high-fidelity, high-sensitivity imaging on a 23m baseline. We are now pushing to image the first rocky planet in the habitable zone around a nearby Sun-like star. In this talk we present an overview of the LBTI’s design and capabilities, illustrated by recent science highlights, and outline future developments and observing projects.
13095-6
On demand | Presented live 17 June 2024
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GLINT is a nulling interferometer downstream of the SCExAO extreme-adaptive-optics system at the Subaru Telescope (Hawaii, USA), and is a pathfinder instrument for high-contrast imaging of circumstellar environments with photonic technologies. GLINT is effectively a testbed for more stable, compact, and modular instruments for the era of ∼30m-class telescopes. GLINT is now undergoing an upgrade with a new photonic chip for more achromatic nulls, and for phase information to enable fringe tracking. Here we provide an overview of the motivations for the GLINT project and report on the design of the new chip, the on-site installation, and current status.
13095-7
17 June 2024 • 14:20 - 14:40 Japan Standard Time | Room G416/417, North - 4F
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The Fiber Imager foR a Single Telescope (FIRST) is a visible spectro-interferometer (600-760 nm, R~400) installed on the Subaru telescope's extreme adaptive optics platform (SCExAO). It provides high-precision spatial coherence measurements with high angular resolution (~8 mas at 656 nm, ~1% coherence accuracy) by combining light from sub-apertures of the telescope pupil. We present two upgrades of the instrument towards H𝛼 detection of protoplanets. We report on the integration of a new 4000-resolution spectrograph and on the sensitivity of the instrument. We also present the characterisation of a high performance visible photonic integrated circuit prototype used for the interferometric combination of 5 sub-apertures.
13095-8
An update on the Navy Precision Optical Interferometer
(Invited Paper)
17 June 2024 • 14:40 - 15:10 Japan Standard Time | Room G416/417, North - 4F
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We will present the status of the Navy Precision Optical Interferometer. We will discuss upgrades that occurred over the course of the last couple of years, their related scientific achievements, ongoing and future work. We will discuss the improvements done to the infrastructure of the site, the return to observations with 6 telescopes simultaneously and the results of these observations. We will discuss the deployment of new capabilities, such as an infrared beam combiner, siderostat controllers and a new angle tracker. We will also present the deployment of the Amon Hen hypertelescope experiment and changes done to the inner room in order to accommodate the use of both systems without the need of large rearrangements of the optics.
Session 3:
Current and Planned Facilities III
17 June 2024 • 15:40 - 17:30 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Alexander Chaushev, Univ. of California, Irvine (United States)
13095-9
The VLTI in the GRAVITY+ era (VLTI status update)
(Invited Paper)
17 June 2024 • 15:40 - 16:10 Japan Standard Time | Room G416/417, North - 4F
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The VLTI continues to develop along the lines of its 2017 roadmap. A new 200 meter AT baseline is now available, pushing the VLTI angular resolution and imaging capability. The second generation instruments GRAVITY and MATISSE continue delivering outstanding results. The continued developments of the VLTI, especially with the UTs, are now happening under the umbrella of the GRAVITY+ project. Fringe tracking has significantly improved following an upgrade of the GRAVITY fringe tracker and the completion of GRAVITY for MATISSE. The wide off-axis capability of the interferometer, in science operation with GRAVITY wide, is now delivering key science results. The imminent installation of the new UT adaptive optics GPAO will soon improve the high-contrast and short wavelength performance on bright objects. The addition of laser guide stars in 2025 will do the same for much fainter targets.
13095-10
On demand | Presented live 17 June 2024
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In the GRAVITY+ project, GRAVITY is currently undergoing a series of upgrades
to improve its performance and sky coverage. Some aspects of the latter have
already been commissioned at the end of 2021 and are available to the
community. GRAVITY+ Wide increases the maximum angular separation between the
celestial science object and the fringe tracking object from previously
2 arcseconds to 20–30 arcseconds (limited by the atmosphere). We will cover the
implementation of phase 2 which will transfer the differential optical path
length control to the VLTI beam compressors to improve optical throughput and
the bandwidth of the vibrational control.
13095-11
On demand | Presented live 17 June 2024
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The Very Large Telescope Interferometer (VLTI) is a wonderful infrastructure for long-baseline interferometry. MATISSE, the Multi AperTure mid-Infrared SpectroScopic Experiment, installed at the VLTI focus, accesses high resolution imaging over a wide spectral domain of the mid-infrared. The instrument is a spectro-interferometric imager operating in the L, M, and N transmission windows and combining four optical beams from the VLTI’s unit or auxiliary telescopes.
We propose at the SPIE conference to advertise the use of the MATISSE. We will illustrate the instrument capabilities through astrophysical results recently achieved. We will show how user can obtain support in their use of MATISSE for their favorite programs. We will also show what are the expected future infrastructure optimizations and instrument adaptations (off-axis tracking, frame of GRAVITY+) that will permit to push the sensitivities and accuracies for the forward developments of the astrophysical programs in the context of the JWST.
13095-12
On demand | Presented live 17 June 2024
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ESO’s Very Large Telescope Interferometer has a history of record-breaking discoveries in astrophysics and significant advances in instrumentation.
The next leap forward is its new visitor instrument, called Asgard.
It comprises four natively collaborating instruments: HEIMDALLR, an instrument performing both fringe tracking and stellar interferometry simultaneously with the same optics, operating in the K band; Baldr, a Strehl optimizer in the H band; BIFROST, a spectroscopic combiner to study the formation processes and properties of stellar and planetary systems in the Y-J-H bands; and NOTT, a nulling interferometer dedicated to imaging nearby young planetary systems in the L band.
The suite is in its integration phase in Europe and should be shipped to Paranal in 2025.
In this article, we present details of the alignment and calibration unit, the observing modes, the integration plan, the software architecture, and the roadmap to completion of the project.
13095-13
17 June 2024 • 17:10 - 17:30 Japan Standard Time | Room G416/417, North - 4F
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BIFROST is the short-wavelength, high-spectral resolution instrument in the Asgard Suite of VLTI visitor instruments. It will be optimized for spectral line studies in the Y, J, and H bands (1.05-1.75 μm) that include many strong lines & molecular features. In this presentation, we outline the BIFROST science drivers that have guided our design choices and map them against the operational modes that are being implemented. We give an overview about the status of the project and the milestones from the ongoing integration & testing phase in Exeter to shipping & commissioning on Paranal, scheduled for 2025 and 2026. We review the BIFROST subsystems and discuss how they interface with the broader Asgard Suite. Finally, we outline other BIFROST-related activities pursued by our group that are intended for implementation in BIFROST as part of future upgrades.
Tuesday Plenary
18 June 2024 • 08:30 - 10:00 Japan Standard Time | National Convention Hall, 1F
View Full Details: spie.org/AS/tuesday-plenary
13173-502
The present and future of Japan's space program
(Plenary Presentation)
18 June 2024 • 08:30 - 09:15 Japan Standard Time | National Convention Hall, 1F
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The Basic Plan on Space Policy sets forth the basic principles of Japan's space policy with an aim to promote policies for space development. The latest version, approved by the Cabinet in June 2023, marks a significant shift by defining space science as a crucial integral part of Japan's space development efforts, transitioning from treating it solely as an isolated academic activity. For instance, the Artemis program is promoted as a policy initiative where scientific exploration is positioned to serve a precursor role. It also encourages Japan’s involvement in NASA's post-JWST efforts. Here, I will present Japan's recent accomplishments and future plans in space science.
13173-503
NASA astrophysics: from today to the Habitable Worlds Observatory
(Plenary Presentation)
18 June 2024 • 09:15 - 10:00 Japan Standard Time | National Convention Hall, 1F
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The goals of the Astrophysics Division are to understand how the universe works, understand how we got here and to address the question, are we alone? In this talk, Dr. Clampin will discuss the current goals of the Astrophysics Division, and its suite of current and future missions. He will also preview progress towards the 2020 National Academies (NAS) Decadal Survey including the key recommendation, the Habitable Worlds Observatory and NASA’s approach to its implementation. Dr. O’Meara will discuss the first steps towards implementation, the formation of a Science, Technology, Architecture Review Team (START) and Technical Analysis Group (TAG) for HWO. He will describe how these teams, along with a large cohort of volunteers are working to define the trade space that must be explored for HWO to meet its top science goals of surveying exoplanets for the signatures of life and performing transformational astrophysics.
Session 4:
Current and Planned Facilities IV
18 June 2024 • 10:30 - 12:10 Japan Standard Time | Room G416/417, North - 4F
Session Chairs:
Jens Kammerer, European Southern Observatory (Germany), Stephanie E. Sallum, Univ. of California, Irvine (United States), Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
13095-14
On demand | Presented live 18 June 2024
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NOTT (formely Hi-5) is the L’-band (3.5-4.0 μm) nulling interferometer of Asgard, an instrument suite in preparation for the VLTI visitor focus. The primary scientific objectives of NOTT include characterizing (i) young planetary systems near the snow line, a critical region for giant planet formation, and (ii) nearby main-sequence stars close to the habitable zone, with a focus on detecting exozodiacal dust that could obscure Earth-like planets. In 2023-2024, the final warm optics have been procured and assembled in a new laboratory at KU Leuven. First fringes and null measurements were obtained using a Gallium Lanthanum Sulfide (GLS) photonic chip that was also tested at cryogenic temperatures. In this paper, we present an overall update of the NOTT project with a particular focus on the cold mechanical design, the first results in the laboratory with the final NOTT warm optics, and the ongoing Asgard integration activities. We also report on other ongoing activities such as the characterization of the photonic chip, the development of the exoplanet science case, the design of the dispersion control module, and the progress with the self-calibration data reduction software.
13095-15
On demand | Presented live 18 June 2024
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The Magdalena Ridge Observatory Interferometer is an ambitious project to build a 10 telescope long-baseline optical/near-infrared array in the mountains about 1 hour outside of Socorro, NM. We are currently funded via a cooperative agreement with the AFRL in Albuquerque, NM to demonstrate imaging capabilities on geosynchronous objects. We have installed the second beamline of the MROI and are working towards first fringes on an 8m baseline. We report on the status of each of the subsystems, the installation progress and challenges to date, and plans for science with the facility as it comes online.
13095-16
On demand | Presented live 18 June 2024
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The Magdalena Ridge Observatory Interferometer has been designed to deliver an unprecedented capability for model-independent imaging of faint astronomical targets. Its design methodology has focused on optimizing the interferometric sensitivity of all of its sequential opto-mechanical subsystems. We report here on initial on-sky testing of one of the MROI beam-trains, outlining the performance metrics utilized to characterize the elements of the optical train from the Unit telescopes through to the MROI beam combiner tables, the tests performed on each subsystem, and how our results compare to the design error budget for the MROI. The impact of the tests on the initial sensitivity limit of the MROI are discussed.
13095-17
Stellar intensity interferometery: from Narrabri to CTA
(Invited Paper)
On demand | Presented live 18 June 2024
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In the early 1960's a new stellar interferometer began to emerge in dusty outback NSW. The highly unorthodox design was the brainchild of Robert Hanbury Brown and Richard Twiss and was led from the University of Sydney. The technology represents the culmination of a pioneering series of experiments which were accepted by radio engineers, but which courted controversy when performed in the optical, generating skepticism (and worse) from some of the most eminent physicists of the day. These critics were eventually silenced by the overwhelming success of the Narrabri Stellar Intensity Interferometer which made outstanding contributions to fundamental stellar physics. The diameter and effective temperature scale for hot stars was based on data only matched more than a 60 years later. However NSII's most profound legacy is as the foundational experiment in the field now known as Quantum Optics. Recent years have seen a resurgence of interest with several air Cherenkov arrays with large collectors, including the emerging CTA, building an intensity interferometer backend. This review will draw lessons from the past and help inform prospects for the future from this enduring technique.
Session 5:
Current and Planned Facilities V
18 June 2024 • 13:40 - 14:30 Japan Standard Time | Room G416/417, North - 4F
Session Chairs:
Jens Kammerer, European Southern Observatory (Germany), Stephanie E. Sallum, Univ. of California, Irvine (United States), Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
13095-18
A new version of the stellar intensity interferometry instrument for the ASTRI Mini-Array telescopes
On demand | Presented live 18 June 2024
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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 an array of nine Imaging Atmospheric Cherenkov Telescopes to study gamma-ray sources at very high energy (TeV) and perform optical stellar intensity interferometry observations.
The ASTRI Stellar Intensity Interferometry Instrument (SI3) is a fast single photon counting instrument for performing intensity interferometry observations of bright stars with the ASTRI Mini-Array. During 2023 SI3 underwent a significant redesign, with an optical fiber positioned on the focal plane to feed the detectors and electronics. Here we present this new baseline design of SI3, and the motivations behind this choice, including the possibility of future upgrades of the instrument.
We will also show the first results of the target selection procedure based on simulations. Stars with angular diameters of less than 500-600 microarcseconds up to about magnitude 4.5 will be observable. Thanks to the 36 simultaneous baselines offered by the nine telescopes, accurate (up to ~1%) angular measurements can be obtained with 10-30 hours of observations.
13095-19
On demand | Presented live 18 June 2024
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The Planet Formation Imager (PFI) Project is dedicated to defining a next-generation facility that can answer fundamental questions about how planets form, including detection of young giant exoplanets and their circumplanetary disks. The proposed expansive design for a 12-element array of 8m class telescopes with >1.2 km baselines would indeed revolutionize our understanding of planet formation and is technically achievable, albeit at a high cost. It has been 10 years since this conceptual design process began and we give an overview of the status of the PFI project. We also review how a scaled back PFI with fewer large telescopes could answer a range of compelling science questions, including in planet formation and as well as totally different astrophysics areas.
New opportunities make a space-based PFI more feasible now and we give a brief overview of new efforts that could also pave the way for the Large Interferometer for Exoplanets (LIFE) space mission.
Session 6:
Critical Subsystems I
18 June 2024 • 14:30 - 15:30 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Elsa Huby, Lab. d'Etudes Spatiales et d'Instrumentation en Astrophysique (France)
Show Abstract +
MATISSE is the 2nd generation mid-infrared (3.0 µm to 12.0 µm) spectro-interferometric instrument of the Very
Large Telescope Interferometer (VLTI). It was designed to deliver its advertised performance when supported by
an external fringe tracker. This proceeding gives an historical account of how the fringe tracker of the GRAVITY
instrument, another 2nd generation K-band spectro-astrometric instrument of VLTI, became this external fringe
tracker. For a more technical and performance-oriented description of the GRAVITY for MATISSE project,
Woillez, Petrov, et al. (2024)1 should be consulted.
13095-21
On demand | Presented live 18 June 2024
Show Abstract +
Scaling up interferometry to 8m collectors should smooth-out the optical piston perturbations and allow a slow fringe tracker to obtain high precision correction on faint targets. In practice, the GRAVITY fringe tracker still observes high frequency OPD components that limit the exposure time, its precision and limiting magnitude.
Perturbations seem to come from mechanical vibrations in the train of mirrors. As part of the GRAVITY+ efforts, accelerometers were added to all the mirrors of the coudé train to compensate in real-time the optical path using the main delay lines. We show their effectiveness on vibrations peaks between 40 and 200Hz and outline prospects for the upgrade of the deformable mirrors and the beam-compressor differential delay lines.
13095-22
18 June 2024 • 15:10 - 15:30 Japan Standard Time | Room G416/417, North - 4F
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The GRAVITY+ project is providing a major upgrade of the VLTI facility and its instruments. At the heart of this upgrade is the implementation of four Wavefront Sensors units, enabling both Natural Guide Star and Laser Guide Star operations on the UTs. Here, we present the implementation and testing of the Wavefront Sensor units in Europe, before their installation in Paranal. As originally envisionned for VLTI, GRAVITY+ will make real the implementation of fully NGS and LGS AO-assisted interferometry on 8m class telescopes, paving the way for a new revolution in sensitivity, sky coverage and high-contrast at VLTI.
Session 7:
Critical Subsystems II
18 June 2024 • 16:00 - 17:00 Japan Standard Time | Room G416/417, North - 4F
Session Chairs:
Jens Kammerer, European Southern Observatory (Germany), Stephanie E. Sallum, Univ. of California, Irvine (United States), Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
13095-23
18 June 2024 • 16:00 - 16:20 Japan Standard Time | Room G416/417, North - 4F
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The GRAVITY instrument has transformed the field of near-infrared interferometry and is redefining the limits of ground-based observations. In Galactic Center observations, this is shown by routinely achieving below 50 μas uncertainty on astrometric measurements within a 5-minute exposure and detecting stars fainter than 19th magnitude. Nevertheless, systematic effects are still limiting the instrument's performance. In this talk, I will introduce two observing modes to overcome these limitations: Pupil modulation to improve the astrometry and metrology attenuation to overcome SNR limitations. I will detail these two modes and show how significant the improvements are on examples of on-sky data.
13095-25
On demand | Presented live 18 June 2024
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Asgard/NOTT is an ERC-funded project hosted at KU Leuven and is part of a new visitor instrumental suite, called Asgard, under preparation for the Very Large Telescope Interferometer (VLTI). Leveraging nulling capabilities and the long VLTI baselines, it is optimized for high-contrast imaging of the snow line region around young nearby main-sequence stars. This will enable the characterization of the atmosphere of young giant exoplanets and warm/hot exozodiacal dust with spectroscopy in the L’-band (3.5-4.0 µm). In this work, we present the first lab assembly of the instrument done at KU Leuven and the technical solutions to tackle the challenge of performing nulling in the mid-infrared despite the thermal background. The opto-mechanical design of the warm optics and the injection system for the photonic chip are described. The alignment procedure used to assemble the system is also presented. Finally, the first experimental results, including fringes and null measurements, are given and confirm the adequacy of the bench to test and optimize the Asgard/NOTT instrument
13095-26
18 June 2024 • 16:40 - 17:00 Japan Standard Time | Room G416/417, North - 4F
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As the high-contrast visitor instrument for VLTI, the NOTT aims to detect and characterize young exoplanets in the mid-infrared L’ band through nulling interferometry. This report outlines recent advancements in component fabrication via ultrafast laser inscription on GLS samples. Laboratory characterization, conducted on a 4-spectral interferometric testbench, is the first detailed mid-infrared characterization of such a photonic chip in its complete four-telescope nulling configuration, demonstrates favorable throughput, achromatic splitting ratios, and self-calibrated nulling performance within the 3.65-3.85 µm range. These achievements align with the specific requirements of NOTT, marking significant progress in meeting its specifications for high-precision observations.
Wednesday Plenary
19 June 2024 • 08:30 - 10:00 Japan Standard Time | National Convention Hall, 1F
View Full Details: spie.org/AS/wednesday-plenary
13173-504
Euclid mission: first year of operations
(Plenary Presentation)
19 June 2024 • 08:30 - 09:15 Japan Standard Time | National Convention Hall, 1F
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After launch on 1 July 2023, the Euclid space telescope of the European Space Agency (ESA) has begun its 6-year mission designed to understand the origin of the Universe's accelerating expansion, which is commonly associated with Dark Energy. By observing billions of galaxies, Euclid will create a 3-dimensional map of the Universe covering 10 billion years of cosmic history. It contains the hierarchical assembly of (dark) matter in galaxies, clusters and superclusters telling us about the nature of gravity and giving us a detailed measurement of the accelerated expansion of the Universe in time. The stringent image quality and sky survey requirements impose extreme performances of the telescope, instruments, and spacecraft. After a mission summary, I will describe the in-orbit spacecraft and instrument performances. A notable challenge is the processing of the large volume of data. The scientific prospects of Euclid are illustrated with the first images and early science results.
13173-505
The ultraviolet explorer: new views of the UV universe
(Plenary Presentation)
19 June 2024 • 09:15 - 10:00 Japan Standard Time | National Convention Hall, 1F
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The Ultraviolet Explorer (UVEX) mission, scheduled for launch in 2030, advances three scientific pillars: exploring the low-mass, low-metallicity galaxy frontier; providing new views of the dynamic universe, and leaving a broad legacy of modern, deep synoptic surveys adding to the panchromatic richness of 21st century astrophysics. The UVEX instrument consists of a single module with simultaneous FUV and NUV imaging over a wide (10 sq. deg) FOV and sensitive R>1000 spectroscopy over a broad band from 1150 - 2650 Angstroms. In this talk I will describe the UVEX scientific program and provide an overview of the instrument and mission.
Session 8:
Technologies I
19 June 2024 • 10:30 - 12:00 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Alexander Chaushev, Univ. of California, Irvine (United States)
Show Abstract +
Over the past two decades, photonics have been developed as technological solutions for astronomical instrumentation for, e.g., near-infrared spectroscopy and long baseline interferometry. With increasing instrument capabilities, large quantities of high precision optical components are required to guide, manipulate, and analyze the light from astronomical sources. Photonic integrated circuits (PICs) and fiber-based devices offer enormous potential for astronomical instrumentation, as they can reduce the amount of bulky free-space optics and pave the way for innovative solutions. Astrophotonic devices are particularly interesting for interferometry due to their compact design on the centimeter scale, even for a large number of telescope inputs. Already, astrophotonic components are integrated in high-end instruments at the VLTI and at the CHARA Array. Photonic beam combiners at wavelengths from visible to mid-infrared have been fabricated using lithographic techniques or ultrafast laser inscription, with several components tested on-sky. This talk will provide a glimpse into the growing field of astrophotonics, its current status and potential for new technologies.
13095-28
On demand | Presented live 19 June 2024
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The Photonic Lantern Nuller (PLN) is an instrument concept designed to characterize exoplanets within a single beam-width from its host star. The PLN leverages the spatial symmetry of a mode-selective photonic lantern (MSPL) to create nulled ports, which cancel out on-axis starlight but allow off-axis exoplanet light to couple. The null-depths are limited by wavefront aberrations in the system as well as by imperfections in the lantern’s response. However, wavefront sensing and control can be used to improve the null-depths achievable. We present schemes for wavefront control with a PLN, as well as simulations and in-lab testbed results.
13095-29
On demand | Presented live 19 June 2024
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Photonic lanterns (PLs) are tapered waveguides that gradually transition from a few-mode fiber geometry to a bundle of single-mode fibers (SMFs). The SMF outputs are highly stable due to spatial filtering and are sensitive to low-order spatial features in the input scene, making them suitable for studying angular scales beyond the diffraction limit. One of the promising techniques with PLs is spectroastrometry, which measures wavelength-dependent shifts in the center of light, ideal for studying objects whose morphology changes with wavelength. To be able to recover spectroastrometric signals (center of light) in each wavelength, one needs to understand the chromatic behavior of PLs. We characterize the spectral response of a near-infrared 3-port PL installed on the SCExAO instrument at the Subaru telescope in J and H bands. The results are compared to numerical simulations. Then we present an experimental demonstration of measuring the center of light as a function of wavelength. Additionally, we introduce strategies for calibrating astrometric signals using dispersed PL outputs in the presence of time-varying wavefront errors.
13095-30
On demand | Presented live 19 June 2024
Show Abstract +
Nulling interferometry is a promising technology to enable prospecting for and characterising sub-stellar companions at extremely close separations and high contrasts. The most scientifically rewarding observations will require extremely well corrected wavefronts in order to deliver consistent, deep nulls that suppress the flux from the central star. We present a two stage system whose first stage deploys a hybrid mode-selective photonic lantern to optimally inject starlight into a single mode fibre. The architecture also yields wavefront corrections that are free of non-common path errors. Repeated over multiple telescopes, a second-stage kernel nuller chip implemented as an operating mode of Bifrost in the Asgard instrument suite. This operating mode will enable a variety of science cases including constraining the entropy of formation of giant exoplanets, studying debris disk formation and surveying lensing events for the detection of black holes. We illustrate candidate designs and present early simulations of the modules, finding that Seidr is a feasible means of capitalising a historical window of opportunity to further high contrast and high angular resolution imaging.
Session 9:
Technologies II
19 June 2024 • 13:30 - 14:20 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Nic Scott, CHARA Array (United States)
13095-145
Heterodyne IR interferometry and technologies for kilometric baseline interferometry
(Invited Paper)
19 June 2024 • 13:30 - 14:00 Japan Standard Time | Room G416/417, North - 4F
13095-31
19 June 2024 • 14:00 - 14:20 Japan Standard Time | Room G416/417, North - 4F
Show Abstract +
For Very Long Baseline Interferometry high-resolution imaging of exoplanets, an astrophotonic-based aperture synthesis concept is proposed for high-resolution direct imaging of exoplanets. A silicon photonic chip incorporates microheaters and optical phase shifters for precise control of delays and phase synchronization from widely separated receivers. A satellite laser guide star with a modulated optical signal serves as a global phase reference, enabling high-speed, high-stroke phase compensation and combining. The chip's design addresses challenges such as atmospheric turbulence and phase stability in optical frequencies. The study outlines the current proof-of-concept instrument status, measured performance, chip fabrication, and routes towards photonics-enabled exoplanet imaging.
Session 10:
Aperture Masking Interferometry I
19 June 2024 • 14:20 - 15:30 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
13095-32
Aperture masking interferometry in astronomy: from pre-AO diffraction limited imaging to space interferometry with JWST
(Invited Paper)
19 June 2024 • 14:20 - 14:50 Japan Standard Time | Room G416/417, North - 4F
Show Abstract +
Aperture masking interferometry (AMI) transforms a conventional telescope into an interferometric array via a pupil plane mask. By enforcing a known and often linear relationship between pupil-plane phase errors and Fourier phases, AMI allows for the calculation of “self-calibrating” Fourier observables. This enables imaging at moderate contrast down to and inside the classical telescope diffraction limit. AMI’s earliest applications resulted in sub-diffraction-limited angular resolution without adaptive optics. Subsequent observations coupled with powerful adaptive optics systems extended AMI’s reach to fainter targets and longer exposure times, opening doors to a wide range of studies of binaries, protoplanetary disks, and evolved massive stars. AMI has recently led to the first use of interferometry in space via the mask aboard the James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph (JWST/NIRISS). I will give an overview of AMI’s technical and scientific progress over the years, beginning with ground-based studies and ending with a performance analysis of space-based AMI with JWST/NIRISS.
13095-33
On demand | Presented live 19 June 2024
Show Abstract +
The Slicer Combined with an Array of Lenslets for Exoplanet Spectroscopy (SCALES) will be the first facility-class integral field spectrograph (IFS) to operate between 2-5 microns. Expected to see first light at W. M. Keck Observatory in 2025, SCALES will extend the parameter space of directly imaged exoplanets to those that are colder, and thus older. SCALES will perform high-contrast imaging of these objects and other targets including protoplanetary disks, Solar System objects, and supernovae. Interferometric techniques such as non-redundant aperture masking (NRM) have been demonstrated to improve spatial resolution at high contrasts. Aperture masking turns a telescope into an interferometer by blocking the pupil with an opaque mask with some number of circular holes. Here we present the final designs for the non-redundant masks that will be integrated into SCALES. We outline their design, manufacturing, characterization, and integration processes. We also present the injection and recovery of several planet and disk companion models into mock SCALES science frames to assess the performance of the selected designs.
13095-34
On demand | Presented live 19 June 2024
Show Abstract +
The enduring technique of aperture masking interferometry, now more than 150 years old, is still widely practised today for it opens a window of high angular resolution astronomy that remains difficult to access by any competing technology. However, the requirement to apodise the pupil into a non-redundant array dramatically limits the throughput, typically to 10% or less. This in turn has a dramatic impact on the sensitivity so that only bright classes of science have been targeted. This paper presents ``Jewel masks'', a novel technology that leverages the gains in signal fidelity conferred by non-redundant Fizeau beam combination without the sensitivity penalty incurred by traditional aperture masks. Our approach fragments the pupil with a set of phase wedges, producing several sets of sparse-array tilings. After extensive searching, solutions were found where all individual sets are fully non-redundant. Each set is assigned a common phase wedge which diverts that pattern onto a defined region of the sensor. We describe transmissive and reflective implementations, as well as a case study of a VAMPIRES mask with realistic fabrication errors.
Session 11:
Aperture Masking Interferometry II
19 June 2024 • 16:00 - 17:20 Japan Standard Time | Room G416/417, North - 4F
Session Chairs:
Jens Kammerer, European Southern Observatory (Germany), Stephanie E. Sallum, Univ. of California, Irvine (United States), Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
13095-35
On demand | Presented live 19 June 2024
Show Abstract +
The VAMPIRES instrument combines polarimetry and interferometry to deliver unique observational reach into the astrophysics of the high contrast, immediate stellar environment of evolved stars - which are historically difficult to study. This work presents the performance of VAMPIRES’ upgraded polarimetric non-redundant aperture masking mode. Enhancements in sensitivity, a lower noise floor, and the ability to perform simultaneous measurement at four wavelength bands in the 600-800 nm region are all reported. New empirically-constrained analysis of the instrumental contribution to VAMPIRES polarised light signals enables a dramatic improvement in processing of recovered data, with new scientific outcomes for evolved star mu Cephei, which suggest there is polarised asymmetry closer to the stellar surface than previously thought. We present a novel image reconstruction method - a convolutional neural network which simultaneously reconstructs sub-diffraction limited images across polarisation states. The enhanced performance of the upgraded VAMPIRES, when coupled with model fitting developments, highlight the crucial role VAMPIRES is playing in probing previously unobservable physics.
13095-36
On demand | Presented live 19 June 2024
Show Abstract +
Protoplanetary disks are the best place for observing planetary embryos. Direct imaging coupled with interferometric techniques, such as non-redundant masking (NRM), can help us better understand gas giant accretion timescales and dynamical interactions by imaging protoplanetary disks that exhibit evidence of planet formation. By using NRM we can achieve angular resolution down to and within the diffraction limit, and image planet formation on solar system scales. We present progress on a direct imaging survey designed to search for protoplanets embedded in protoplanetary disks with NRM and a case study of the V892 Tau circumbinary disk. The goals of this survey have been to detect and characterize protoplanets at solar system scales in a significant sample of protoplanetary disks and to characterize disk structure and dynamical interactions. From this survey, we can place constraints on the underlying protoplanet population and timescales under which giant gas planets form at spatial separations down to ~7 AU.
13095-37
19 June 2024 • 16:40 - 17:00 Japan Standard Time | Room G416/417, North - 4F
Show Abstract +
The James Webb Space Telescope Aperture Masking Interferometer provides NIRISS with its highest angular resolution imaging mode, an ultra-stable non-redundant masking Fizeau interferometer. Until recently, the precision of its interferometric visibilities has been limited to ~ 1% by systematic uncertainties in its optical state and detector noise properties. Using a data-driven calibration of AMI with a differentiable forwards model, this can be improved by more than an order of magnitude, uniquely enabling high angular resolution science not possible from the ground. We will discuss the pipeline and observing strategies required to achieve this, illustrated with science highlights enabled this way from the first two years of AMI data, and generalizations of this approach to kernel phase interferometry.
13095-38
On demand | Presented live 19 June 2024
Show Abstract +
The Aperture Masking Interferometer (AMI) on board the James Webb Space Telescope (JWST) has a unique place in observational astronomy as the first imaging interferometer in space, promising highly-precise observations resistant to optical aberrations. While the optical system and Point Spread Function (PSF) are very stable, the infrared detectors on board suffer from a series of non-linearities that, while challenging for other observing modes are ruinous to the visibility calibration of AMI mode. Efforts using the existing pipelines have delivered some improvements, but outcomes remain far from the theoretical instrumental limit. This manuscript presents initial work using a fundamentally different approach: the joint implementation of a differentiable physics model of the optics, and a machine-learned Effective Detector Model (EDM), using dLux. These are trained together end-to-end, by gradient descent using the full ensemble of point-source reference targets so far observed by AMI. We infer highly-precise metrology of the AMI and NIRISS optical systems and a preliminary EDM which restores commissioning data to near-ideal precision.
Thursday Plenary
20 June 2024 • 08:30 - 10:00 Japan Standard Time | National Convention Hall, 1F
View Full Details: spie.org/AS/thursday-plenary
13173-506
Navigating the radio astronomy renaissance: challenges and opportunities for a sustainable future
(Plenary Presentation)
20 June 2024 • 08:30 - 09:15 Japan Standard Time | National Convention Hall, 1F
Show Abstract +
The next decade heralds a renaissance in radio astronomy, with a formidable complement of global Observatories, from LOFAR2.0, to the SKA becoming powerful discovery engines at these lowest frequencies. While they commit to lowering data access barriers, managing the deluge of data poses challenges, as the new constraint on viable astronomy must move from hours on sky to data product cost in energy, compute and carbon and data footprint. I will explore with you the challenges and opportunities in creating a new frontier of sustainable, ethical, affordable astronomy.
13173-507
The X-Ray Imaging and Spectroscopy Mission (XRISM): development and expected science
(Plenary Presentation)
20 June 2024 • 09:15 - 10:00 Japan Standard Time | National Convention Hall, 1F
Show Abstract +
The X-Ray Imaging and Spectroscopy Mission (XRISM) project was initiated in 2018 as the recovery mission resuming the high-resolution X-ray spectroscopy with imaging once realized but unexpectedly terminated by a mishap of ASTRO-H/Hitomi. XRISM carries a pixelized X-ray micro-calorimeter array and an X-ray CCD on the focal planes of two sets of X-ray mirror assemblies. The spacecraft was successfully launched from JAXA Tanegashima Space Center on September 7, 2023, and is now conducting performance verification observation followed by guest observations starting in August 2024. In this paper, we present the history of development and recent results.
Session 12:
Data Processing, Analysis, Access, and Discovery I
20 June 2024 • 10:30 - 12:00 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
13095-39
I2C@2024: an interferometric imaging contest in 2024
(Invited Paper)
On demand | Presented live 20 June 2024
Show Abstract +
Images in optical long-baseline interferometry have seen a boost in the recent years thanks to new techniques and recipes invented by the community. These images are more and more used for science interpretation and not only illustration, and their fidelity has improved significantly, thanks mainly to the increase in the number of telescopes used in interferometers. The focus today is to improve their reliability and dynamic range. With this contest, we follow up the quest introduced in 2004 of comparing the state of the art image reconstruction software for long-baseline interferometry. This is done in a festive way in the form of an imaging contest, where the organisers propose simulated datasets of targets, whose brightness distributions are meant to be blindly retrieved using various algorithms by the contestants. A prize is offered to the winner of the contest. This year is not different from previous ones and we proposed to the contestants tools to compare their reconstructed images with original images. These tools are now distributed, together with example datasets and images, enabling further tests at home of any image reconstruction tool.
13095-40
20 June 2024 • 11:00 - 11:20 Japan Standard Time | Room G416/417, North - 4F
Show Abstract +
More than 5000 exoplanets have been discovered to date, yet the formation and early evolution of gas giant planets remains an unsolved puzzle. Taking advantage of the contrast gain obtained by combining adaptive optics with interferometric observations, we present a VLTI/GRAVITY survey of young, directly imaged gas giant planets to unveil their formation history. The observations provide astrometric data of unprecedented accuracy, being crucial for refining the planets’ orbital parameters and illuminating their dynamical histories. Repetitive observations of the exoplanets at medium spectral resolution (R ~ 500) provide a catalogue of K-band for a number of our targets, revealing molecular signatures from e.g., CO, H2O, CH4, and CO2. With the help of self-consistent atmosphere models and atmospheric retrievals, the physical parameters and the C/O ratio of the planets can be constrained, kick-starting the difficult process of linking planetary formation with measured atomic abundances. In the near future, the GRAVITY+ upgrade will enable the observation of even fainter and closer-in exoplanets.
13095-41
On demand | Presented live 20 June 2024
Show Abstract +
We report progress on Project Prime (PRecision Interferometry with MIRC for Exoplanets) to detect exoplanets using precision closures using MIRC-X and MYSTIC at CHARA. Our investigations include modeling systematics caused by OPD drifts, differential dispersion, beamtrain birefringence, and flatfielding errors. Injection tests suggest we can recover hot Jupiter companions as faint at 1/5000 of the host star brightness with 4 nights of observing and we will present some results of our recent searches for the hot Jupiters. Our upper limits are starting to constrain current-generation Global Circulation Models (GCMs). We propose the addition of modest nulling (10:1) to today's interferometers in order to vastly increase the ease of this work and to open up many more targets for detections.
13095-42
On demand | Presented live 20 June 2024
Show Abstract +
Discovering new actively-accreting protoplanets is the most direct way of studying the planet formation process. However, so far, only two protoplanets have been unambiguously identified; PDS 70 b and c. A limiting factor in the hunt for new protoplanets are the large distances to star-forming regions (> 130pc), which in turn requires extreme angular resolution. To overcome these limitations we have developed a kernel phase interferometry (KPI) program for the SCExAO/CHARIS IFS. KPI is a data processing technique that is capable of detecting companions down to 𝝺/2D (as opposed to ~𝝺/D), when using a conventional telescope with an adaptive optics system. This makes KPI a promising technique for find new young protoplanets.
Session 13:
Data Processing, Analysis, Access, and Discovery II
20 June 2024 • 13:30 - 15:10 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Jens Kammerer, European Southern Observatory (Germany)
13095-43
20 June 2024 • 13:30 - 13:50 Japan Standard Time | Room G416/417, North - 4F
Show Abstract +
We present latest results and further development of the image reconstruction tool GRAVITY-RESOLVE (G^R), which is specifically designed for Galactic Center observations with the near-infrared phase-referencing VLTI instrument GRAVITY. We show deep images of the Galactic Center in recent years and movies in which the stellar motion around the central massive black hole SgrA* becomes apparent on yet unmatched scales. Moreover, we present a first result of the newly implemented mosaicing method in G^R to jointly reconstruct multiple datasets which have been separately recorded on sky.
13095-44
On demand | Presented live 20 June 2024
Show Abstract +
Interferometry, essential in radio and infrared astronomy, faces a significant challenge: reconstructing images from sparsely sampled data. Current regularized minimization algorithms rely heavily on predefined priors and hyperparameters, leading to ambiguities and inaccuracies in the images. Here, we present a project to integrate Neural Networks into interferometric image reconstruction. By utilizing the principles of Compressed Sensing and generative Neural Networks, this approach can map infrared interferometric data to reconstruct images more accurately, reducing reliance on rigid priors. The adaptability of the Neural Network ensures that the reconstructions are more precise and less dependent on user input, which is a significant advancement over current methods that require extensive expertise. In this work, we present, as software demonstration, reconstructions obtained from the Event Horizon Telescope data of the black-hole shadow at the core of M87.
13095-45
On demand | Presented live 20 June 2024
Show Abstract +
Nulling interferometry is a powerful observing technique to reach exoplanets and circumstellar dust at separations too small for direct imaging with single-dish telescopes and too large for indirect methods.
With near-future instrumentation, it bears the potential to detect young, hot planets near the snow lines of their host stars.
A future space mission could detect and characterize a large number of rocky, habitable-zone planets around nearby stars at thermal-infrared wavelengths.
The null self-calibration is a method aiming at modelling the statistical distribution of the nulled signal.
It has proven to be more sensitive and accurate than average-based data reduction methods in nulling interferometry.
This statistical approach opens the possibility of designing a GPU-based Python package to reduce the data from any of these instruments, by simply providing the data and a simulator of the instrument.
\texttt{GRIP} is a toolbox to reduce nulling and interferometric data based on the statistical self-calibration method.
In this article, we present the main features of GRIP as well as applications on real data.
13095-46
On demand | Presented live 20 June 2024
Show Abstract +
The newly installed Silmaril beam combiner at the CHARA array is designed to observe previously inaccessible faint targets, including Active Galactic Nuclei and T-Tauri Young Stellar Objects. Silmaril leverages cutting-edge optical design, low readout noise, and a high-speed C-RED1 camera to realize its sensitivity objectives. In this presentation, we offer a comprehensive overview of the instrument's software, which manages critical functions, including camera data acquisition, fringe tracking, automatic instrument alignment, and observing interfaces, all aimed at optimizing on-sky data collection. Additionally, we offer an outline of the data reduction pipeline, responsible for converting raw instrument data products into the final OIFITS used by the standard interferometry modeling software. Finally, a thorough analysis of the camera and instrument characterization results will be presented, evaluating instrument performance in terms of sensitivity. The purpose of this paper is to provide a solid reference for studies based on Silmaril data.
13095-47
On demand | Presented live 20 June 2024
Show Abstract +
The delivery of curated data from astronomical instruments has become a reality in many observatories. The European Southern Observatory (ESO) delivers science-ready data products for various instruments, ranging from imagers to integral field spectrographs. In the case of infrared long-baseline interferometry, scientists generally make their own curated data available through the Optical Interferometry Database (OiDB) once published. In this communication, we report on a project to create a curated data stream for the GRAVITY instrument at the Very Large Telescope Interferometer. We aim to transform the publicly available raw data in the ESO science archive into science-ready curated data.
Session 14:
Space Interferometry Technology I
20 June 2024 • 15:40 - 16:50 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Gerard T. van Belle, Lowell Observatory (United States)
13095-48
The Large Interferometer For Exoplanets (LIFE): a space mission for mid-infrared nulling interferometry
(Invited Paper)
On demand | Presented live 20 June 2024
Show Abstract +
The Large Interferometer For Exoplanets (LIFE) is a proposed space mission that enables the spectral characterization of the thermal emission of exoplanets in the solar neighborhood. The mission is designed to search for global atmospheric biosignatures on dozens of temperate terrestrial exoplanets and it will naturally investigate the diversity of other worlds. Here, we review the status of the mission concept, discuss the key mission parameters, and outline the trade-offs related to the mission’s architecture. In preparation for an upcoming concept study, we define a mission baseline based on a free-formation flying constellation of a double Bracewell nulling interferometer that consists of 4 collectors and a central beam-combiner spacecraft. The interferometric baselines are between 10–600 m, and the estimated diameters of the collectors are at least 2 m (but will depend on the total achievable instrument throughput). The spectral required wavelength range is 6–16 µm (with a goal of 4–18.5 µm), hence cryogenic temperatures are needed both for the collectors and the beam combiners. One of the key challenges is the required deep, stable, and broad-band nulling performance while ma
13095-49
On demand | Presented live 20 June 2024
Show Abstract +
Infrared nulling interferometery in space is the most promising technique for detecting possible signs of life on earth-like exoplanets, through the combination of ozone and other biomarkers. The LIFE mission concept extends on earlier work by Darwin and TPF-I with a modern mission concept. I will describe why spatial filtering is critical in the context of both adaptive nulling and alternative approaches in order to achieve the ~10^7 contrast needed, and describe why a endlessly single mode photonics crystal waveguide fed by phase induced amplitude apodisation optics is the currently preferred option for LIFE. Finally, I will discuss technological options we are considering and prototyping for production of such a waveguide spatial filter at different wavelengths, including both fibres and laser micromachining of infrared crystals.
13095-50
On demand | Presented live 20 June 2024
Show Abstract +
The Large Interferometer For Exoplanets (LIFE) is a proposed space-based mid-infrared nulling interferometer aimed at directly detecting dozens of temperate, terrestrial exoplanets and investigating their atmospheres for their composition and potential biosignatures.
Getting realistic performance estimates for LIFE requires a comprehensive understanding of all major noise sources impacting its measurements. Previous studies on the performance of LIFE have focused on astrophysical noise and assumed the impact of instrumental noise to be non-dominant.
Here, we report on our ongoing effort to explicitly model instrumental noise for LIFE. We consider two different methods: one providing a numerical solution by propagating the errors in Monte Carlo simulations, and one providing an analytical solution using a second-order approximation of the leakage from instrumental instability noise. We give an overview of the two methods and argue in favor of the numerical method to support the efforts of the LIFE initiative in the ongoing concept phase, due to its flexibility for different observatory architectures and its fidelity in modeling the correlation of errors.
Michelson and Fizeau Prize Awards
20 June 2024 • 16:50 - 17:20 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Gerard T. van Belle, Lowell Observatory (United States)
The conference chairs will announce the winners of the Michelson and Fizeau Prizes.
Session 15:
Space Interferometry Technology II
21 June 2024 • 09:00 - 10:00 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Edgar R. Ligon, CHARA Array (United States)
Show Abstract +
In recent years, there has been a renewed interest in technology development for space-based optical and infrared interferometry. One such pathfinder is Pyxis, a set of three autonomous robotic platforms designed to operate in the carpark of Mt Stromlo Observatory, Canberra, where it will simulate formation-flying while performing optical interferometry. In this paper, we will provide an update on the interferometer, detailing the initial results of the control subsystems. We will also share our future plans to begin space qualification and adaptation of Pyxis into a set of nano-satellites.
13095-52
On demand | Presented live 21 June 2024
Show Abstract +
The Large Interferometer For Exoplanets (LIFE) is an envisioned mid-infrared (MIR) space mission. A key requirement for this mission is to demonstrate the performance of a broad-band nulling interferometric beam-combiner, capable of blocking the starlight by a factor of 10^6 while being sensitive enough to detect faint planet light. This is the aim of the Nulling Interferometer Cryogenic Experiment (NICE), a test bench dedicated to demonstrating the null stability and sensitivity over a reasonable bandwidth. The instrument has to be cryogenically cooled below 15K to suppress the thermal background and to achieve the required sensitivity limits. The development of NICE is divided into a warm and a cryogenic phase. In this presentation, we discuss the status of the warm phase, the optical concept of NICE, the opto-mechanical implementation including the efforts on the stabilization of the setup, and the results of the performance measurements.
13095-53
On demand | Presented live 21 June 2024
Show Abstract +
Optical interferometers have produced the first resolved images of main-sequence stellar surfaces by using long co-phased baselines, and correcting for atmospheric errors using fringe tracking and closure phases. However, the astronomical targets suitable for ground based interferometric imaging remain limited. A spaceborne formation flying optical interferometer could potentially image dimmer targets with longer baselines, but must still contend with disturbances like propulsive stationkeeping and attitude control system noise. This work simulates on-orbit fringe tracking controller performance under representative disturbances for a small three-spacecraft Michelson interferometer. Assuming CubeSat-sized subapertures, we investigate fringe tracker design options for a low cost demonstration mission that could complement ground-based stellar surface imaging capabilities.
Session 16:
Space Interferometry Technology III
21 June 2024 • 10:30 - 11:40 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Cyprien Lanthermann, CHARA Array (United States)
13095-54
Artemis-enabled Stellar Imager (AeSI): a Lunar long-baseline UV/optical imaging interferometer
(Invited Paper)
On demand | Presented live 21 June 2024
Show Abstract +
NASA’s return to the Moon presents a unique chance for scientific breakthroughs. Inspired by past NASA studies, such as for the Stellar Imager Vision Mission, we aim to take advantage of the Artemis lunar infrastructure. Our AeSI project has secured Phase 1 support from NIAC (NASA Innovative Advanced Concepts) to investigate the feasibility of building a high-resolution, long-baseline, UV/optical imaging interferometer on the lunar surface, in conjunction with the Artemis Program. This concept study for a lunar surface-based interferometer will be a huge step forward to larger arrays on both the moon and free-flying in space, over a wide variety of wavelengths and science topics. Our Phase 1 study began in April 2024 and in this invited talk we outline our vision and provide updates on the progress made to-date.
13095-55
On demand | Presented live 21 June 2024
Show Abstract +
This work aims to present mid-infrared (L-band) astrophotonic chips made in Lithium Niobate by classical lithographic and ion:diffusion techniques. We present building blocks such as Y-splitters, directional couplers, unbalanced beam splitters optimised for the L band. In particular, a 4 telescope mid-IR combiner (linked to the NOTT project) was made in order to achieve nulling interferometry. We show that we have lower loss waveguides, controlled photometric splitters, as well as the implementation of the electro-optic effect in the chips. This will allow us to real-time balance the coupling ratio, or finely tune the fringes, therefore improving the contrast, allowing for a step further into compact nulling interferometry.
13095-56
On demand | Presented live 21 June 2024
Show Abstract +
For high angular resolution observations in far-infrared and terahertz frequencies, development of intensity interferometers using fast SIS photon detector is presented. Fast measurement of photon bunches enables measurement of delay time, which can be used for aperture synthesis imaging. Laboratory demonstrator was developed using a 4-K pulse-tube cooler, a He4 sorption cooler, and SIS photon detectors with fast readout electronics. Optical evaluation of detector performance as well as measurement of intensity fluctuation of a high temperature blackbody source is on-going to realize measurement of intensity correlation and delay time measurements. Application to Antarctic terahertz interferometers and space-borne far-infrared interferometers will be discussed.
Session 17:
Future of Interferometry I
21 June 2024 • 11:40 - 12:30 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Jens Kammerer, European Southern Observatory (Germany)
13095-57
Astrophotonics: the visible path forward in interferometry
(Invited Paper)
21 June 2024 • 11:40 - 12:10 Japan Standard Time | Room G416/417, North - 4F
Show Abstract +
While the angular resolution is the obvious driver for pushing instruments in the visible wavelength range, working with short wavelengths comes with challenges. In this presentation I will review the latest developments regarding photonic developments for the recombination of beams in the visible. Photonic devices constitute a promising avenue for the future instrumentation in interferometry, offering compact, stable and potentially complex architectures. Especially in the context of the spectro-interferometer FIRST installed on the SCExAO platform at the Subaru Telescope, we are exploring two different manufacturing technologies producing waveguides with low or high refractive index contrast. I will review the main challenges we are facing, regarding insertion and propagation losses, as well as polarization effects, and introduce current research developments towards visible design for active phase modulation devices, 3D-architectures and photonic lanterns.
13095-58
On demand | Presented live 21 June 2024
Show Abstract +
Microarcsecond resolutions afforded by an optical-NIR array with kilometer-baselines would enable breakthrough science. However significant technology barriers exist in transporting weakly coherent photon states over these distances: primarily photon loss and phase errors. Quantum telescopy, using entangled states to link spatially separated apertures, offers a possible solution to the loss of photons. We report on an initiative launched by the NSF’s NOIRLab in collaboration with the Arizona Quantum Initiative at the University of Arizona, Tucson, to explore these concepts further. A brief description of promising science cases and a possible technology roadmap towards a quantum-enhanced very long baseline optical-NIR interferometric array are presented. An on-sky demonstration of measuring spatial coherence of photons with apertures linked through the simplest Gottesman protocol over short baselines and with limited phase fluctuations is envisaged as the first step.
Session 18:
Future of Interferometry II
21 June 2024 • 14:00 - 15:30 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Joel Sanchez-Bermudez, Univ. Nacional Autónoma de México (Mexico)
13095-59
On demand | Presented live 21 June 2024
Show Abstract +
We demonstrate a proof-of-principle, table-top experiment of a quantum stellar interferometer by interfering a path-entangled single photon generated from parametric down conversion and the light collected from a single spectral-temporal mode, quasi-thermal source representing an astronomical source. The interference signal was used to recover the spatial autocorrelation of double-slit source distributions. We compare this to a theoretical model and see good agreement, allowing further comparison to other weak, non-single-photon, local-oscillator sources such as coherent states. Using the knowledge gained from this experiment, we give an update with our plans to extend to true thermal and astronomical sources.
Show Abstract +
Stellar spatial intensity interferometry was first demonstrated by Hanbury-Brown and Twiss in the 1950s as a viable tool to determine the angular diameters of stars, and was later formulated by Roy Glauber into the quantum theory of optical coherence. This technique is based on the characteristic photon bunching property of thermal light, including blackbody radiation such as starlight, and so allowed access to angular resolutions beyond the individual telescope's diffraction limit when used with optical aperture synthesis.
Stellar temporal intensity interferometry however has not been met with similar success. We will discuss some of the technical challenges that have constrained its development, and present our prototype instrumentation towards enabling it into a potentially useful tool for astrophysics.
13095-61
Providing user support and community development
(Invited Paper)
On demand | Presented live 21 June 2024
Show Abstract +
The optical/infrared interferometry community is a vibrant, active community. Nonetheless, the technique is not without its challenges.In this talk I will address the various activities in which we try to engage and stimulate the community to maximize the impact and output of optical/infrared interferometry instrumentation such as the VLTI. I will, in particular, focus on activities that aim to provide user support and expand the optical/infrared interferometry community.
Show Abstract +
The Big Fringe Telescope (BFT) is a facility concept under development for a next-generation, kilometer-scale optical interferometer. Observations over the past decade from routinely operational facilities such as CHARA and VLTI have produced groundbreaking scientific results, reflecting the mature state of the techniques in optical interferometry. However, routine imaging of bright main sequence stars remains a surprisingly unexplored scientific realm. Additionally, the 3+ decade old technology infrastructure of these facilities leads to high operations \& maintenance costs, and limits performance. We are developing the BFT, based upon robust, modern, automated technologies with low capital construction and O\&M costs, in support of kilometer-scale optical interferometers that will open the door to regular `snapshot' imaging of main sequence stars. Focusing on extreme angular resolution for bright objects leads to substantial reductions in expected costs through use of COTS elements and simplified infrastructure.
Session 19:
Future of Interferometry III
21 June 2024 • 16:00 - 16:40 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Stephanie E. Sallum, Univ. of California, Irvine (United States)
13095-62
21 June 2024 • 16:00 - 16:20 Japan Standard Time | Room G416/417, North - 4F
Show Abstract +
The European Interferometry Initiative (EII; https://european-interferometry.eu/) is an open association of Institutes from 15 European countries collaborating on the exploitation and development of optical/infrared long baseline interferometry. Since its formation in the early 2000s the EII has fostered the development of interferometry in Europe and worldwide through programmes that develop the technology for making interferometric observations, support existing users of interferometry facilities, and encourage new generations of users to learn about and exploit interferometry for science observations. We discuss the successes and lessons learned in the delivery of the programmes initiated and managed by the EII, including the development of new hardware, software and techniques, the initiation of the VLTI Expertise Centres to support users, and training and networking through the VLTI summer schools and the Fizeau exchange programme. We discuss possible future programmes to further support and develop the interferometry community.
13095-63
On demand | Presented live 21 June 2024
Show Abstract +
Astronomy at far-infrared (far-IR) wavelengths is essential to our understanding of the evolution of the cosmos. However, an absence of high angular resolution observations in the far-IR, from roughly 30-300 µm) inhibits our ability to address important science questions, and due to the opacity of Earth’s atmosphere, a space-based solution is needed. Here we envisage what a far-IR Great Observatory class mission might look like in the context of the Origins Space Telescope (OST) and the Space Infrared Interferometric Telescope (SPIRIT), and consider multiple point designs for a two element, structurally connected spatial-spectral space-based far-IR interferometer.
Session 20:
Thesis Prize, Open Discussion, and Wrap Up
21 June 2024 • 16:40 - 17:00 Japan Standard Time | Room G416/417, North - 4F
Session Chair:
Stephanie E. Sallum, Univ. of California, Irvine (United States)
The conference chairs will award the Thesis Prize, and lead an open discussion and conference wrap-up.
Session PS1:
Posters - Current and Planned Facilities
17 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
View
Monday Poster Session schedule and event details
Each day includes a unique set of posters. Poster groupings are listed below by topic.
Show Abstract +
The CHARA Array has added a 7th telescope to extend the existing 6 telescope array. The CHARA Michelson Array Pathfinder (CMAP) is a 1m Planewave RC Telescope mounted in a custom designed mobile trailer and pier system. The telescope and trailer can be placed at multiple locations around the Mount Wilson Observatory site; each site consisting of a flat concrete pad with a novel pier design. Optical fibers connect the site to the CHARA optical delay and combiner lab. This enables new short baselines of ~15m for imaging the surfaces of large stars and new long baselines on the order of ~600m for resolving small stars. Initially, there are two sites at the array for this telescope. In the future, there are plans to expand to greater than 1 km maximum baselines. These baselines will be used in conjunction with the existing 15 baselines that range from 34 to 331m. Moving such a telescope around the observatory presents some unique challenges. The telescope can make use of the same optical delay lines and beam combiners as the other CHARA Array telescopes.
13095-66
On demand | Presented live 17 June 2024
Show Abstract +
The goal of the CHARA Array Integrated Optics Testbench (CHARIOT) is to establish a fully characterized interferometry setup for on-sky tests of novel astrophotonic 2D or 3D beam combiners for the interferometry community worldwide. CHARIOT is planned for four telescope beams covering the J-, H-, and K-bands with plug-and-play fiber interfaces.
Verifying novel astrophotonics on-sky with CHARIOT will enable the development of components and advances in instruments in many fields, including nulling and spectro-interferometry.
13095-68
On demand | Presented live 17 June 2024
Show Abstract +
MIRC-X and MYSTIC, operating at the CHARA Array, are advanced six-telescope beam combiners covering J, H, and K bands (1.1-2.2 μm). They enable imaging of stellar objects with high sensitivity, reaching 8.1 mag in H and 7.8 mag in K-band. In 2022 a 4-beam gravity IO combiner was added to MYSTIC with the goal of improving sensitivity. Ongoing developments include software upgrades and instrument enhancements. Planned upgrades for MIRC-X and MYSTIC include adding high-resolution spectral modes, automating the mode-switching process, improving broadband coverage, and boosting the sensitivity for both instruments by around one magnitude
13095-69
17 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
Show Abstract +
Direct imaging and spectroscopy of exoplanets is challenging due to the small angular separation and high contrast between the planets and their host stars. We present a novel technique that combines nulling interferometry and high-resolution spectroscopy to address the challenge. We will present the laboratory results, modular design for telescope/instrument interface, future development, and the science cases that the technique enables at facilities such as the Large Binocular Telescope and future extremely large telescopes.
13095-70
On demand | Presented live 17 June 2024
Show Abstract +
Directly imaging habitable-zone exoplanets and obtaining their spectra is the central goal in exoplanet science; however, this is extremely challenging due to the high contrasts and small angular separations required. The Guided Light Interferometric Nulling Technology (GLINT) instrument on the SCExAO system at the 8.2-meter Subaru telescope in Hawaii, utilises nulling interferometry photonically for high-contrast imaging of circumstellar environments. To produce high starlight suppression and deeper nulls, it is necessary to correct seeing-induced wavefront error through fringe tracking and active fringe modulation. For GLINT, fringe tracking is embedded within a control loop designed to enhance the instrument’s sensitivity. This involves manipulating the wavefront using MEMS deformable mirrors and continuously optimising the position of motorised alignment components. Here, we present an overview of this real-time control loop, which is encapsulated within a Graphical User Interface (GUI).
13095-71
On demand | Presented live 17 June 2024
Show Abstract +
A photonic integrated circuit (PIC) is a lightweight and compact alternative to bulk optics but is often lossy with a small operating bandwidth. The Fibered Imager foR a Single Telescope (FIRST) instrument, an interferometer installed on the Subaru telescope, aims to detect exoplanets/companions in the 600 to 800 nm visible bandwidth by differential measurements of H-alpha emissions to the host star. In its integrated optical version, FIRST PIC, this is achieved through the pairwise combination of five sub-apertures. We introduce a novel design for FIRST PIC, fabricated by LioniX International, doubling the current PIC transmission with an 80% predicted throughput with no crosstalk. A high index difference between the waveguide and cladding material was selected to allow for compact circuits, offering the potential for a high input number and complex designs. New components have been designed for this PIC, including broadband tapered directional couplers and tri-couplers to maximize the overall throughput across the entire bandwidth. Experimental performance, focusing on polarization and wavelength response, is discussed, concluding with insights for future PIC improvements.
Show Abstract +
We present in this proceeding the results of the test phase of the GRAVITY+ adaptive optics. This extreme
AO will enable both high-dynamic range observations of faint companions (including exoplanets) thanks to a
40x40 sub-apertures wavefront control, and sensitive observations (including AGNs) thanks to the addition of a
laser guide star to each UT of the VLT. This leap forward is made thanks to a mostly automated setup of the
AO, including calibration of the NCPAs, that we tested in Europe on the UT+atmosphere simulator we built in
Nice. We managed to reproduce in laboratory the expected performances of all the modes of the AO, including
under non-optimal atmospheric or telescope alignment conditions, giving us the green light to proceed with the
Assembly, Integration and Verification phase in Paranal.
13095-73
On demand | Presented live 17 June 2024
Show Abstract +
The BIFROST instrument is poised to revolutionize high-spectral resolution interferometry within the VLTI framework by extending the accessible wavelength range down to 1.0 micrometres, encompassing the Y, J, and H bands. In this paper, we discuss the optical design for BIFROST's pre-injection optics that corrects for birefringence effects and longitudinal dispersion between the different beam lines. We present the optomechanical design for the light injection module that compresses the beams and injects them into single-mode fibers, while maintaining the full field-of-view of the VLTI auxiliary or unit telescopes. Our fiber switching module will allow injecting the lights into photonics devices optimised for different wavebands or applications. Finally, we outline our integration & alignment strategy and present first characterisations result obtained in the optics lab at Exeter.
13095-74
On demand | Presented live 17 June 2024
Show Abstract +
We present the instrumentation design and implementation a dual-field light source for the calibration and design of the BIFROST instrument. The system consists of a beam expander and a beam splitter with associated mirrors to create the off-axis beam. The performance of this calibration source (called VANAHEIM) is tested in both Zemax opticstudio and with laboratory testing.
13095-75
On demand | Presented live 17 June 2024
Show Abstract +
The BIFROST instrument is part of the Asgard Suite of VLTI visitor instruments. It is an interferometric beam combination instrument optimised for high-resolution spectroscopy. Due to the similarities with the MIRCX instrument at CHARA the BIFROST control software framework uses the MIRCX software as a starting point. We make modifications to the MIRCX software to account of the differences between BIFROST and MIRCX, such as the choice of actuators, and differences to the optical design. Many of the changes are also required to take account of the requirements of VLTI, including the use of an ESO-compliant gateway computer between the Asgard network and VLTI. This includes implementing a system of observing templates that complement the user interaction GUIs in use at MIRCX.
13095-76
On demand | Presented live 17 June 2024
Show Abstract +
The recent progress of the 100m-baseline optical interferometer is introduced. Nanjing Institute of Astronomical Optics & Technology (NIAOT) is now building a 100-meter-long baseline telescope array in PMO’s(Purple Mountain Observatory) XuYi Observation Station.The telescope array consists of tree 600mm telescopes with a max baseline of 100 meters.
13095-77
17 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
Show Abstract +
The details of the experimental system for 100m-baseline interferometer are provided. The system is a reduced version of 100m-baseline interferometer which is in build in PMO's(Purple Mountain Observatory) XuYi Observation Station. The recent progress is introduced too.
13095-85
On demand | Presented live 17 June 2024
Show Abstract +
BIFROST is a new, high spectral resolution visitor instrument for the Very Large Telescope Interferometer (VLTI). It is one of the four instruments that form the Asgard suite and will be capable of observing on- and off-axis targets simultaneously.
BIFROST will utilise an integrated optics device, fed by single mode fibers. It will use a Light Injection Module (LIM) to couple the starlight from the VLTI into the single mode fibers.
The LIM is not only responsible for coupling the starlight but must co-phase BIFROST with the other instruments of Asgard; optimise flux injection; select the off-axis field, and co-phase the off-axis and on-axis fields. In order to maximize sensitivity, we have developed a novel design which utilizes only 5 optical elements to achieve this functionality.
Here we detail the design of the LIM, highlighting its novel functionality and discuss the next steps in its development.
Session PS2:
Posters - Current and Planned Facilities II
18 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
View
Tuesday Poster Session schedule and event details
Each day includes a unique set of posters. Poster groupings are listed below by topic.
13095-78
On demand | Presented live 18 June 2024
Show Abstract +
A new generation of optical intensity interferometers are emerging in recent years taking advantage of the existing infrastructure of Imaging Atmospheric Cherenkov Telescopes (IACTs). The MAGIC SII (Stellar Intensity Interferometer) in La Palma, Spain, has been operating since its first successful measurements in 2019 and its current design allows it to operate regularly. The current setup is ready to follow up on bright optical transients, as changing from regular gamma-ray observations to SII mode can be done in a matter of minutes. A paper studying the system performance, first measurements and future upgrades has been recently published. MAGIC SII’s first scientific results are the measurement of the angular size of 22 stars, 13 of which with no previous measurements in the B band.
More recently the Large Sized Telescope prototype from the Cherenkov Telescope Array Observatory (CTAO-
LST1) has been upgraded to operate together with MAGIC as a SII, leading to its first correlation measurements
at the beginning of 2024. MAGIC+CTAO-LST1 SII will be further upgraded by adding the remaining CTAO-LSTs. This shows a feasible technical solution to extend SII to the whole CTAO
13095-79
On demand | Presented live 18 June 2024
Show Abstract +
In commissioning the second telescope and first fringe observations at Magdalena Ridge Observatory Interfer-
ometer (MROI) the Free-space Optical multi-apertUre combineR for IntERferometry (FOURIER) will be used
for fringe tracking during early commissioning while awiting the readiness of the Infrared Coherencing Neares
Neighbor (ICoNN) Tracker.1 FOURIER is an image plane beam combiner which can accommodate three beams
and has wavelength coverage from approximately 1 μm to 2.5 μm in approximately 100 wavelength channels,
resulting in a spectral resolution of approximately 100. We have chosen to use a group-delay fringe-tracking
approach and have implemented a configurable search-and-track algorithm. We have also created an operator
interface for controlling the fringe tracker and displaying status information and data. A simulator that sends
simulated data to the fringe tracker and accepts delay corrections from the fringe tracker can be used to test
the fringe tracker under different conditions. We will describe the algorithms and their software implementa-
tion, as well as the user interface. Then we will present results of simulations showing expected fringe-tracking
performance
Session PS3:
Posters - Critical Subsystems
18 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
View
Tuesday Poster Session schedule and event details
Each day includes a unique set of posters. Poster groupings are listed below by topic.
13095-80
On demand | Presented live 18 June 2024
Show Abstract +
The Vacuum Can Hub (VCH) is a network Modbus message processor and instrumentation hub that connects the vacuum can instrumentation to the MROI power and communication infrastructure via a single Power over Ethernet (PoE) access point, greatly simplifying baseline reconfiguration and setup time. The VCH is part of the MROI’s Beam Relay System, a network of vacuum pipes optically linking the MROI’s Unit Telescopes with the Beam Combining Facility, where fringes are collected. The observatory Automated Alignment System is tasked with maintaining alignment of the beamlines by monitoring and controlling instrumentation interfaced with each VCH unit.
13095-81
On demand | Presented live 18 June 2024
Show Abstract +
The Beam Relay System at the Magdalena Ridge Observatory Interferometer, exposed to outdoor environmental conditions, includes 6-inch mirrors mounted on aluminum frames and steel platforms, equipped with piezoelectric motors and a laser/camera alignment system. This subsystem faces challenges with significant misalignments that disrupt observations, addressed by a proposed correction strategy. The system uses temperature sensor data around mirrors to predict and correct misalignments as a feedforward control system through calibrated motors, and incorporates a periodic closed-loop control system using light source and camera. Advanced predictive models refined over time using temperature, shear, and tilt data, aim to maintain beam stability within interferometric tolerances, ensuring optimal performance.
13095-82
On demand | Presented live 18 June 2024
Show Abstract +
Beam misalignment causes visibility loss in fringe measurements made by long-baseline optical interferometers. An Automated Alignment System (AAS) has been designed for the Magdalena Ridge Observatory Interferometer (MROI) to keep the visibility loss associated with misalignment under ~1% .
Production versions of collimated reference light sources and precision beam alignment sensors for the AAS have recently been integrated into the first beamline of the MROI. This paper describes the lessons learned during their installation and provides results from their site acceptance tests.
13095-83
On demand | Presented live 18 June 2024
Show Abstract +
To leverage the angular resolution of interferometry at high contrast, one must employ specialized beam-combiners called interferometric nullers.
Nullers discard part of the astrophysical information to optimize the recording of light present in the dark fringe of the central source.
Asgard/NOTT will deploy a beam-combination scheme offering good instrumental noise rejection when phased appropriately, but for which information is degenerate on the outputs, prompting a dedicated tuning strategy using the science detector.
The dispersive effect of water vapor can be corrected with prisms forming a variable thickness of glass. But observations in the L band suffer from an additional and important chromatic effect due to longitudinal atmospheric dispersion coming from a resonance of CO2 at 4.3µm. To compensate for this effect efficiently, a novel type of compensation device will be deployed leveraging a gasz cell of variable length at ambient pressure.
After reviewing the impact of water vapor and CO2, we present the design of this atmospheric dispersion compensation device and describe a strategy to maintain this tuning on-sky.
13095-84
On demand | Presented live 18 June 2024
Show Abstract +
BIFROST, an upcoming instrument for the VLTI, is part of the Asgard Suite, a VLTI visitor instrument. It comprises two spectrograph arms that are optimised for wavelength range of 1- 1.75 \textmu m (fed by a fiber that is placed on-axis for fringe tracking/monitoring) and 1-1.3 µm (fed by a fiber that can positioned either on-axis or off-axis to observe a faint target) wavelength range, respectively. Volume phase holographic gratings (VPHGs) are employed to achieve high spectral resolving power up to 25,000 and a throughput above 75\% for all dispersing elements. In this contribution, we discuss the optical and optomechanical design of the spectrographs, as well as a new relay optics design that minimizes the thermal background, with a factor 4 reduction in thermal background compared to the non-relay optics design. We will also present the first lab results obtained with the YJH spectrograph.
13095-86
On demand | Presented live 18 June 2024
Show Abstract +
GRAVITY+ project consists of instrumental upgrades to the Very Large Telescope Interferometer (VLTI), for faint-science, high-contrast, milliarcsecond interferometric imaging. As an integral part of the GRAVITY+ Adaptive Optics (AO) architecture, the Wavefront Sensor (WFS) corrects image distortions caused by the turbulence of Earth's atmosphere. We present the WFS' opto-mechanical design and design strategies used to implement two payloads positioned diagonally opposite to each other - Natural Guide Star (NGS) and Laser Guide Star (LGS), within a single compact design structure. We discuss the implementation of relative motions of the two payloads covering the complete patrol field, and that of a nested motion, within the LGS Payload, covering the complete Sodium layer profile in the Earth's atmosphere.
13095-87
18 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
Show Abstract +
Since its introduction at the Very Large Telescope Interferometer (VLTI), the GRAVITY instrument has emerged as a key player in interferometry. Recognizing its substantial contributions, the European Southern Observatory and the GRAVITY consortium have embarked on an initiative to enhance the instrument's functions. This initiative, named GRAVITY+, aims to broaden the instrument's utility for the international astronomical community and foster new areas of research. GRAVITY+ incorporate advanced features such as a novel laser Adaptive Optics system and an improved fringe tracker to augment interferometric observation sky coverage.
This paper details the development of a new Germanium (Ge) prism. This new technical capability of GRAVITY+ will serve to substantially increase the spectral resolution of the instrument to approximately R~15000. The design process, along with the scientific rationale underpinning this advancement, are thoroughly examined in this study.
13095-88
18 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
Show Abstract +
The CHARA Array is presently the world's largest operational optical interferometer, featuring baseline lengths spanning from 34 to 331 meters. It comprises four second-generation beam combiners: SPICA (R-band), MIRCX (JH-band), MYSTIC (K-band), and Silmaril (HK-band). CHARA delivers high-resolution imaging of science objects with angular resolutions reaching up to 0.2 milliarcseconds. At the core of CHARA's operations are the delay lines, equalizes the optical paths of all telescopes as the Earth rotates and corrects optical path variations caused by atmospheric turbulence. The control of these delay lines was upgraded in 2021. In this presentation, we offer an extensive overview of the delay lines' performance, focusing on on-sky fringe visibility measurements. We also share lessons learned experiences, particularly in addressing visibility drops induced by vibrations. Additionally, we present projections regarding the potential performance of upcoming instruments at CHARA, encompassing a nulling instrument and a 1-kilometer baseline interferometer, building building upon our current findings. Finally, we propose future directions to further enhance the delay lines performance.
Show Abstract +
Hierarchical Fringe Trackers (HFT) maximize the sensitivity and accuracy of fringe tracking. Their performances are independent from the number of apertures. They cophase pairs of telescopes, then pairs of pairs and so on. We report the mathematical analysis, design, manufacturing, and optical tests of 4 telescopes HFT chips for the VLTI and 6 to 8 telescopes HFT chips for CHARA. A detailed end-to-end simulation with realistic input piston and flux, based on the experimental characterization of the signals on the test bench, validates the servo loop and state machine architectures and supports the performance analysis, confirming the expected performance gain of about 3 magnitudes and the fact that the performances do not decrease with the number of apertures. Analysis of fringe jumps and losses at the sensitivity limit show that an HFT manages then more efficiently than the standard pairwise architecture. The impact of HFT characteristics on AGN science programs for optical interferometers is discussed, showing that this architecture is the key for fascinating applications including direct distance measurements of AGNs accurate enough to contribute to the Hubble tension problem.
13095-90
On demand | Presented live 18 June 2024
Show Abstract +
Hierarchical Fringe Trackers (HFT) maximize the sensitivity and accuracy of fringe tracking. Their performances are independent from the number of apertures. They cophase pairs of telescopes, then pairs of pairs and so on. We report the mathematical analysis, design, manufacturing, and optical tests of 4 telescopes HFT chips for the VLTI and 6 to 8 telescopes HFT chips for CHARA. This poster presents the detailed end-to-end simulation based on the experimental characterization of the signals on the test bench. We use realistic simulations of atmospheric and instrumental piston and injection fluctuations checked on data recorded from existing fringe trackers on the VLTI and CHARA. We detail the servo loop and state machine architectures and study their optimization to maximize the sensitivity and recover from flux and coherence length losses. We describe the procedure to evaluate the fringe jump rate and recovery delay.
Session PS4:
Posters - Technologies
19 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
View
Wednesday Poster Session schedule and event details
Each day includes a unique set of posters. Poster groupings are listed below by topic.
13095-91
On demand | Presented live 19 June 2024
Show Abstract +
We are developing a “dual-aperture fiber nuller” (DAFN) as a technology to bridge the gap in observation of exoplanets with orbital separations between 1-10s of AU. Such an instrument interferometrically achieves an on-axis (starlight) null while off-axis light (planet light) is transmitted to a high-resolution spectrograph. The performance of the DAFN is competitive among only a few existing technologies such as the vortex fiber nuller. Furthermore, it has the cost-effective advantage of improving angular resolution by expanding the interferometric baseline rather than increasing aperture size. We present a monochromatic demonstration of this technology’s angular resolution (< 1λ/D) and sensitivity to starlight suppression in the lab. The DAFN technology can potentially be deployed to preexisting interferometric frameworks such as the Large Binocular Telescope Interferometer or the Very Large Telescope Interferometer. It can also benefit prospective space-based exoplanet direct imaging missions, e.g. LIFE, as well as ground-based ELT searches for terrestrial planets in the habitable zone.
13095-92
On demand | Presented live 19 June 2024
Show Abstract +
Hydrogen H-alpha (656.2nm) and HeI 1083nm are the spectral lines most commonly used for diagnosing the solar chromosphere. We aim to investigate the scientific advantage in combining these lines in imaging spectroscopic observation using a narrowband tunable filter. Simultaneous imaging in two wavelengths is possible by splitting the light with a polarizing beam splitter attached at the exit of the filter and using two cameras. We have constructed a setup that enables spectroscopic imaging in H-alpha and HeI 1083nm lines almost simultaneously, with a time required for switching the wavelength of about 0.1 second. The full width at half maximum of the transmission in H-alpha is 0.25A, while, with an additional stage of the Lyot filter, it is 0.367A in HeI 1083nm.
In this paper, we describe the overview of the system and demonstrate its observing capability by presenting some examples of observations. We also discuss the advantage of combining these two lines in view of their responses to the physical condition as inferred from a non-LTE calculation.
13095-93
On demand | Presented live 19 June 2024
Show Abstract +
Detecting exoplanets around host stars and characterizing the physical properties of these planets requires unprecedented high-resolution and high-contrast imaging. Achieving this using current large-aperture telescopes and optical interferometers faces several key challenges.
A new alternative to conventional interferometry and huge full apertures (>8m) is the novel hybrid optical telescope (HOT) design, which consists of phase-distributed aperture arrays. The HOT architecture follows an image-plane interferometric setup by placing apertures constructed from lightweight optics on a ring configuration. The interferometric design of HOT can leverage PSF engineering techniques that can locally create contrast levels up to 1e-7 in the image.
We will present results from the analysis of WFS methods for a HOT, including Photon Lanterns, and report on the level of wavefront correction possible for a magnitude range of targets. Based on the WFS analysis, we will report on potential capabilities for achieving quantum-limited super-resolution when imaging faint exo-planets near a host star.
13095-94
On demand | Presented live 19 June 2024
Show Abstract +
Innovation in high angular resolution imaging is essential to identifying solar system scale planet formation in active star forming regions beyond 150 pc. The photonic lantern is a novel fiber-optic device under active development that can be used to overcome these observational challenges. Photonic lanterns spatially filter out modal noise with high throughput and very little power loss, making them appealing for a wide variety of applications including wavefront-sensing, nulling, and spectro-astrometry. Spectro-astrometry is a technique used to identify wavelength-dependent centroid shifts in spectrally-dispersed datasets. Using photonic lanterns for spectro-astrometry would allow us to resolve circumstellar structures beyond the diffraction limit. Here, we present simulations of photonic lanterns for spectro-astrometry. We generate mock, 6-port photonic lantern observations of young stars with gapped circumstellar disks containing accretion hotspots at the Paschen beta hydrogen line. We utilize a Markov-chain Monte Carlo method to recover the properties of both the protoplanetary disks and accretion signatures such as planet/star contrast, separation, and position angle.
13095-95
On demand | Presented live 19 June 2024
Show Abstract +
Starlight suppression techniques for High-Contrast Imaging (HCI) are crucial to achieving the demanding contrast ratios and inner working angles required for detecting and characterizing exoplanets with a wide range of masses and separations. The advent of photonic technologies provides new opportunities to control the amplitude and phase characteristics of light, with the potential to enhance and control starlight suppression. Here, we present a focal plane optical-fiber-based nulling interferometer working with commercially available components for amplitude and phase modulation. The instrument implements single-mode fiber-coupled elements: a MEMS variable optical attenuator (VOA) matches the on-axis and off-axis starlight amplitude, while a piezoelectric-driven fiber stretcher modifies the optical path difference to achieve the π phase shift condition for destructive interference. We show preliminary lab results using a narrowband light source working at 632 nm and discuss future opportunities for testing on-sky with the Astrophotonics Advancement Platform at Lick Observatory (APALO) at the Shane 3-m Telescope.
13095-96
On demand | Presented live 19 June 2024
Show Abstract +
Co-phasing technique is used to detect and compensate the fluctuation of optical path difference (OPD) between sub-telescopes of long baseline optical interferometers caused by atmospheric turbulence. At present, the sensitivity of co-phasing technology is limited. A kind of chromatic phase diversity method (CPD) used to obtain OPD by extracting phase from the optical transfer function of multi-aperture interferometry was proposed in 2014. Compared to other traditional co-phasing or fringe tracking methods, this method is of some significant advantages such as less power loss, larger capture range of piston error and synchronous sensing for all apertures. In the past, the method was verified by bulk optics or integrated photonics chip only combining beams. Wavelength Separation was still accomplished by many dichroics and fold mirrors which would increase light loss. We present a new compact solution that Fizeau multi-axial beam combination and multiple spectral channels can be merged on single photonic chip. Our works including Verifying of CPD algorithm, model simulation and design of the chip on H-band will be introduced respectively.
Show Abstract +
Cross-aperture nulling interferometry can be used to observe exoplanets at smaller separations from their host stars than coronagraphy. This approach is based on the fact that an anti-symmetric focal plane point spread function cannot couple to the symmetric mode of a single mode fiber. Generating an anti-symmetric point spread function can be carried out by means of a pupil-plane phase mask that reverses field directions symmetrically across the center of the pupil, one of the solutions of which is a pupil-plane phase-knife mask with a relative phase shift across a centerline of pi radians. A simple means of providing the needed phase pattern is with geometric phase, which can be provided by a liquid-crystal polymer layer with orthogonally oriented optical axes on the two sides of a pupil bisector. Prototype phase-knife masks of this type have been made, and used to demonstrate central null depths of 2e-5 in the laboratory, a level sufficient for exploring the innermost circumstellar regions with ground-based telescopes. Further steps to mitigating leakage are also discussed.
13095-98
On demand | Presented live 19 June 2024
Show Abstract +
Speckle polarimeter (SPP) is a facility instrument of the 2.5-m telescope of the Caucasian Mountain Observatory of SAI MSU. By design it is a combination of a speckle interferometer and a dual-beam polarimeter. In 2022 we performed a major upgrade of the instrument. New version of the instrument features Hamamatsu ORCA-Quest qCMOS C15550-20UP, having subelectron readout noise, as a main detector, as opposed to EMCCD Andor iXon 897 used in previous version. Optical distortions present in the instrument are considered as they directly affect the accuracy of the speckle interferometric astrometric measurements of binary stars. We identified the Atmospheric Dispersion Compensator (ADC) as the main source of distortions which depend on the rotational angles of ADCs prisms. Distortions are estimated using internal calibration light source. Method for their correction is developed. Flux ratio estimates are subject to CMOS-specific negative factors: spatially correlated noise and flux-dependent pixel-to-pixel sensitivity difference. We suggest ways to mitigate these factors. We discuss the precision of the estimates of position angle, separation and flux ratio of binary stars.
Session PS5:
Posters - Aperture Masking Interferometry
19 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
View
Wednesday Poster Session schedule and event details
Each day includes a unique set of posters. Poster groupings are listed below by topic.
13095-100
On demand | Presented live 19 June 2024
Show Abstract +
Among the technologies pioneered aboard the James Webb Space Telescope (JWST) is the first space-based implementation of infrared interferometry: the Aperture Masking Interferometry mode of the Near Infrared Imager and Slitless Spectrograph (NIRISS/AMI). AMI is a potentially very powerful tool for imaging of a variety of moderate- to high-contrast astronomical sources. The non-redundant mask placed in the pupil of the telescope enables detection of sources below the classical Rayleigh diffraction limit, within the inner working angle of the coronagraphic modes onboard JWST. We will discuss the insights and unique challenges that have been revealed during the commissioning, early calibration, and first science observations of this specialized observing mode, including mitigation strategies for instrumental effects, lessons learned for optimizing operations, observable extraction software packages, and ongoing calibration efforts.
13095-101
19 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
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Many JWST programs take advantage of its infrared sensitivity and highly stable point spread function (PSF) to directly detect faint companions using diverse high-contrast imaging (HCI) techniques. However, periodic re-phasing of the primary mirrors is required due to changes in thermal equilibrium and stochastic tilt events of mirror segments. Many programs observe reference stars to remove the stellar component within an image, consuming nearly half the allocated time. We present a NIRISS HCI technique using the measured wavefront error (WFE) as prior information in a Bayesian analysis to estimate the WFE of an observation and search for companions, without using a reference star. We estimate the WFE for full aperture and aperture masking interferometry modes using three low order Zernike coefficients per hexagonal mirror segment to generate synthetic PSFs and compare to simulations. We compare our technique to traditional interferometric analysis, and recover an injected companion with ΔF430M=8 at 0.2”.
13095-102
On demand | Presented live 19 June 2024
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Aperture masking is a technique to transform a filled-aperture telescope into an interferometer. One reason masks help boost sensitivity is that they facilitate the measurement of closure phases. Closure phases are insensitive to differential piston in the wavefront of light captured by each subaperture, so are a precise observable encoding the structure of the observed object. Spatial structure in the wavefront of light over each subaperture biases visibilities and closure phases. All extant aperture masking data sets show residual closure phase dispersion after calibration larger than estimates based on photon-noise alone, suggesting time variable substructure in the wavefront is playing a role in limiting closure phase precision. We are developing a technique harnessing the capabilities of holographic aperture masks to multiplex subapertures to provide for simultaneous focal-plane wavefront sensing of each subaperture. This device can be used to measure the spatial structure of the wavefront, facilitating self-calibrating closure phases. We will present the results of simulations demonstrating the concept and describe a prototype instrument design.
13095-142
On demand | Presented live 19 June 2024
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Holographic aperture masking (HAM) is an imaging technique in which a conventional telescope pupil is made into an interferometric array by means of a diffractive liquid-crystal phase mask. HAM allows for angular resolutions that approach and surpass the conventional diffraction limit, while simultaneously increasing throughput compared to traditional sparse aperture masking. This technique allows for extraction of phase and amplitude information with low spectral resolution, making it especially useful for the detection of close-in asymmetries such as companions and protoplanetary disks.
We demonstrate the results of on-sky tests with the HAM in the Keck I / OSIRIS imager.
Observations of the known binary HD 44927 and the PSF reference star HD 13249 were taken at J-band (1.28 μm). Using the SAMpy data reduction pipeline and modifying it for the OSIRIS HAM optic, we calculate calibrated closure phases for HD 44927. We constrain astrometric and photometric measurements of the HD 44927 companion, finding agreement in its orbital parameters with previous measurements made using kernel phase interferometry.
Session PS6:
Posters - Data Processing, Analysis, Access, and Discovery
20 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
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Thursday Poster Session schedule and event details
Each day includes a unique set of posters. Poster groupings are listed below by topic.
13095-103
On demand | Presented live 20 June 2024
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The majority of the 5600+ confirmed exoplanets orbit stars that will eventually become white dwarfs (WDs). Very few planets have been discovered around WDs, and none have been directly imaged, which leaves gaps in our knowledge of how planetary systems evolve as stars evolve. Directly imaging planets orbiting WDs poses challenges, as WDs are very faint and the limitations of adaptive optics cause poor ground-based image quality, making it difficult to detect planets orbiting at tight angular separations. While space observatories can offer better image quality, there is a limit to detecting planets at solar system scales, due to their smaller telescope diameters. We utilize the data processing technique of kernel phase interferometry (KPI), boosting angular resolution by a factor of a few to several, to overcome these challenges. We are currently using KPI on archival Hubble Space Telescope data of seven WDs in the Hyades cluster to search for planets that have survived the death of their host star. Applying KPI to this dataset will result in the highest resolution planet search around WDs to date, and it will provide new constraints on post main sequence planetary evolution.
13095-104
On demand | Presented live 20 June 2024
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It has been more than 20 years since optical-interferometric facilities first started producing spectro-interferometric data, and yet the number of general user tools able to handle this type of data properly is limited. Moreover, they often either focus on simple generic cases (e.g., grey simple geometrical models defined with analytical functions) or very specific objects (e.g., binaries, kinematics in emissions lines of circumstellar disks, stellar photospheres). To overcome these limitations, we are developing oimodeler, a python-based optical-interferometric data modelling software allowing to build complex models from various type of components ranging from simple geometrical to external outputs of radiative transfer models. The software allows to add chromaticity (continuum, line and bands) and time-dependence easily. The code is object-oriented to be more flexible and easily expandable. Here we present its implementation and various examples of fitting of real data from various interferometric instruments. The code is available at https://github.com/oimodeler/oimodeler
13095-105
On demand | Presented live 20 June 2024
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The Magdalena Ridge Observatory Interferometer (MROI) will be commissioned with a first generation beam combiner for simultaneous observations in the J, H, and K bands called the Free-space Optical multi-apertUre combineR for IntERferometry (FOURIER). FOURIER is a three beam near infrared beam combiner designed for highly sensitive interferometric observations to take advantage of MROI’s unprecedented sensitivity. We present an overview of the data reduction pipeline under development for FOURIER including its design goals, features, and science objectives.
13095-106
CANCELED: PMOIRED: first two years of enabling science with sparse uv spectro-interferometric data
20 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
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Introduced in 2022, PMOIRED (Parametric Modelling of Optical Interferometric Data) was well received: more than a dozen refereed publication have made use of this code, confirming the need for a modern flexible tool to fit data with sparse u,v plane and rich spectroscopic information. I will review what was learn in the past two years, the features which have been added and the future ones I am working on.
13095-107
20 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
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The VLTI/MATISSE instrument provides interferometric measurements with an angular resolution of only a few milliarcseconds in the mid-infrared. The precision of the observables is essential to interpret them and reconstruct the dusty circumstellar environments as rigorously as possible. I study the variability of the visibilities of some reference stars observed by MATISSE with the atmospheric conditions. The goals are : (i) to find the ambient atmospheric parameters which have the main impact on the visibility measurements; and (ii) to give empirical laws governing the visibility behavior according to these parameters in order to reduce or even cancel their impacts on the measurements. In addition, since the usual uncertainties on the angular diameter of the MATISSE reference stars (mainly K-type giants) is of the order of 10%, I have developed a method to re-estimate their diameter in order to reduce these uncertainties and improve the robustness of the calibrated data.
13095-108
On demand | Presented live 20 June 2024
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Accurate piston error detection and closed-loop control are one of the key technologies to ensure the imaging quality of the interferometric imaging telescope. In this paper, we proposed a piston error detection and control scheme based on three computers and multithreading,which has been successfully applied to a four 0.1-m apertures interferometric telescope.This scheme adopts a kind of fringe contrast measurement and climbing method to achieve closed-loop control. The results implied that the fringe contrast can be raised through piston closed-loop correction. Compared with a single telescope with 0.1-m aperture, we can get a 2.63x improvement in resolution for the new interferometric telescope with four 0.1-m apertures. It is proved that the feasibility and effectiveness of this scheme. We will further carry out astronomical observation experiments and improve the piston error detection and control scheme, in order to provide technical guarantees for the implementation of interferometric imaging telescopes.
13095-147
On demand | Presented live 20 June 2024
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Scattered light in Advanced LIGO disrupts gravitational wave signals, hindering detections. It causes low-frequency noise (20-40 Hz) that interferes with the frequency band where gravitational detections occur (10-100 Hz). Identifying this noise as arches in the time-frequency plane is a critical tool to tracking the scattered light surface. Gravitational waves, predicted by Einstein's General Theory of Relativity, reveal hidden cosmic phenomena. LIGO's upgrades expanded its detection range to 150 Mpc for binary neutron star detections, further increasing the need for detector characterization. To further increase sensitivity, we investigate scattering surfaces with the intent to mitigate scattered light effects. We have created an algorithm used with GravitySpy's machine learning tool to filter noise and study arch properties. Observation Run 4 (O4) data shows that, scattered light occurrences decreased at LIGO Livingston Observatory (LLO), but their characteristics changed. The algorithm accurately calculates arch velocity and frequency in over 90% of cases. Future research will apply it to LIGO Hanford (LHO) data, and we plan to compare the FFT method with the HHT method.
Session PS7:
Posters - Space Interferometry Technology
20 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
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Thursday Poster Session schedule and event details
Each day includes a unique set of posters. Poster groupings are listed below by topic.
13095-109
On demand | Presented live 20 June 2024
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Astronomical space interferometers have the potential to achieve milliarcsecond resolution via formation-flying collectors hundreds of meters apart. The collectors’ role is to transfer the starlight beams to a combiner that coherently interferes them. One challenge is controlling optical distances within a fraction of a wavelength while maneuvering the spacecraft to maintain their relative position. Since measuring relative position is much easier than controlling it, we propose long compact delay lines that significantly relax formation flying requirements. We present a proof-of-concept demonstrating an optical 4-m free-space delay in the lab. The delay line utilizes four high-reflectance mirrors in a configuration that fits within a 10 cm x 20 cm footprint suitable for a CubeSat. We also describe a visible-laser metrology approach that controls the optical path across the 4-m range. The delay line and metrology system would be part of the combiner spacecraft. Such an arrangement will not only relax the relative positioning requirements but also enable a two-spacecraft (total) interferometer that would make a technology demonstration mission more feasible in the near future.
13095-110
On demand | Presented live 20 June 2024
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Formation flying interferometry can increase the distance between satellites compared to ground-based interferometers. However, as the baseline length increases, longer observing time is required to fill the U-V plane. Here, focusing on the continuity of observation wavelengths from space, we develop a method to reconstruct spectra of diffuse objects only by rotating the baseline without changing the baseline length. The proposed method enables future space interferometry, such as the Large Interferometer for Exoplanets (LIFE), to spatially resolve distant objects and obtain their spectra.
13095-111
On demand | Presented live 20 June 2024
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Drones provide a versatile platform for remote sensing and atmospheric studies. However, strict payload mass limits and intense vibrations have proven obstacles to adoption for astronomy. We present a concept for system-level testing of a long-baseline CubeSat space interferometer using drones, taking advantage of their cm-level xyz station-keeping, 6-dof freedom of movement, large operational environment, access to guide stars for end-to-end testing of optical train and control algorithms, and comparable mass and power requirements.
We have purchased two different drone platforms (Aurelia X6 Pro, Freefly Alta X)
and present characterization studies of vibrations, flight stability, gps positioning precision, and more. We also describe our progress in sub-system development, including inter-drone laser metrology, realtime gimbal control, and LED beacon tracking.
Lastly, we explore whether custom-built drone-borne telescopes could be used for interferometry of bright objects over km-level baselines using vibration-isolation platforms and a small fast delay for fringe-tracking.
13095-112
20 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
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Far-infrared (far-IR) astronomical observations with sub-arcsecond angular resolution and high spectral resolution require a space-based interferometer observatory with baselines of at least tens of meters in length. The European-funded Far Infrared Space Interferometer Critical Assessment (FISICA) studied Far Infrared Interferometer (FIRI) in detail, and developed software simulation tools (FIInS and PyFIInS) for modeling a FIRI-like interferometer and simulating the hyperspectral output datacubes. Here we present on-going work expanding upon the foundations of FIInS and pyFIInS towards an end-to-end simulation software suite. The software tools presented in this work provide a framework with which to study double Fourier interferometry in the far-IR and allow the astronomical community further exploration of the unique capabilities of such instrumentation.
13095-113
On demand | Presented live 20 June 2024
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One of the most ambitious goals of modern astronomy is to uncover signs of extraterrestrial biological activity. As the number of rocky exoplanets detected around nearby stars rises, questions about their atmospheric composition, evolutionary trajectory, and habitability increase. Measuring the infrared spectrum of these planets poses significant challenges due to the star/planet contrast and very small angular separation from their host stars.
Recently, we initiated a study with ESA to explore the design parameters and the performances related to an interferometric concept based on a single spacecraft. With a 15m baseline interferometer, the study reveals promising results with over 100 exoplanet detections in the infrared range (3-20μm).
13095-114
On demand | Presented live 20 June 2024
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The far-infrared (FIR; 25 - 350 um) band remains relatively unexplored in astronomy despite its importance for studying the formation and evolution of planets, stars, and galaxies. One factor which limits FIR observing capabilities is the impractically large single aperture telescopes that would be required to achieve the sub-arcsecond angular resolution that has been obtained in the optical and radio bands. A double-Fourier interferometer (DFI) has been proposed, which combines both a spatial interferometer and a Fourier transform spectrometer. Such an instrument, however, is lacking in experimental validation. This work contributes to DFI development by demonstrating the technique for a simple, spectrally uniform source.
13095-115
On demand | Presented live 20 June 2024
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We present our progress in stabilising the warm precursor of the Nulling Interferometry Cryogenic Experiment (NICE), a laboratory testbed demonstrating key mid-infrared nulling technologies for the Large Interferometer for Exoplanets (LIFE). To achieve deep and stable nulls at stellar flux levels, metrology and control systems are essential for mitigating vibrations and drifts during observations, and for optimising throughput and null depth during initial alignment.
A heterodyne laser metrology system was implemented to monitor optical path length differences, beam pointings, and beam positions in NICE. The metrology beams follow the science beams with low non-common paths, and modulation techniques enable simultaneous high-bandwidth measurements of all critical paths through the testbed.
We report on the performance of the control loop and the metrology under ambient conditions, and analyse the current limitations and future improvements of the setup.
Session PS8:
Posters - Future of Interferometry
20 June 2024 • 17:30 - 19:00 Japan Standard Time | Room G5, North - 1F
View
Thursday Poster Session schedule and event details
Each day includes a unique set of posters. Poster groupings are listed below by topic.
13095-116
On demand | Presented live 20 June 2024
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Spectro-interferometry is a powerful technique to study astrophysical objects. All modern interferometric instruments offer at least a limited spectral resolution allowing to probe geometry as the function of the wavelength. Some even offer high-enough resolutions to resolve narrow spectral features allowing to constrain physical, chemical and dynamical properties. However, due to detectors size, current instruments are either limited in term of resolution (up to 4000 for VLTI/GRAVITY to cover the full K-band) or bandwidth (20-50nm). To overcome this limitation, we started investigating the possibility of multi-order Echelle-spectro-interferometry. In such mode, the full spectrum is divided into multiple orders dispersed perpendicularly, taken advantage of the square size of modern detectors. We are currently building a first visible prototype, allowing to simultaneously observe the full R & I photometric bands (600-900nm) with a resolution of R=20000. We the instrumental concept, simulations, our first in-lab results and some driving science programs in the visible and near-infrared.
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