ORCID Profile
0000-0001-7026-6291
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Astronomical and Space Sciences | Astronomical and Space Instrumentation | Astronomy And Astrophysics | Stellar Astronomy and Planetary Systems | Optics And Opto-Electronic Physics | Photonics, Optoelectronics and Optical Communications | Optical Physics | Cosmology and Extragalactic Astronomy | Image Processing | Classical and Physical Optics | Galactic Astronomy | Astronomical sciences | Stellar astronomy and planetary systems | Machine learning not elsewhere classified | Optical technology | Biophysics | Opthalmology And Vision Science | Applied Statistics | Astrobiology |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Physical sciences | Expanding Knowledge in Technology | Scientific instrumentation | Combined operations | Industrial instrumentation | Medical instrumentation | Chemical sciences | Mathematical sciences | Expanding Knowledge in Engineering | Scientific Instruments | Expanding Knowledge in the Information and Computing Sciences
Related Links
Publications
GETTING LUCKY WITH ADAPTIVE OPTICS: FAST ADAPTIVE OPTICS IMAGE SELECTION IN THE VISIBLE WITH A LARGE TELESCOPE
Publisher: American Astronomical Society
Date: 10-02-2009
The Near Infrared Imager and Slitless Spectrograph for the James Webb Space Telescope. IV. Aperture Masking Interferometry
Publisher: IOP Publishing
Date: 2023
Abstract: The James Webb Space Telescope’s Near Infrared Imager and Slitless Spectrograph (JWST-NIRISS) flies a 7-hole non-redundant mask (NRM), the first such interferometer in space, operating at 3–5 μ m wavelengths, and a bright limit of ≃4 mag in W2. We describe the NIRISS Aperture Masking Interferometry (AMI) mode to help potential observers understand its underlying principles, present some s le science cases, explain its operational observing strategies, indicate how AMI proposals can be developed with data simulations, and how AMI data can be analyzed. We also present key results from commissioning AMI. Since the allied Kernel Phase Imaging (KPI) technique benefits from AMI operational strategies, we also cover NIRISS KPI methods and analysis techniques, including a new user-friendly KPI pipeline. The NIRISS KPI bright limit is ≃8 W2 (4.6 μ m) magnitudes. AMI NRM and KPI achieve an inner working angle of ∼70 mas, which is well inside the ∼400 mas NIRCam inner working angle for its circular occulter coronagraphs at comparable wavelengths.
Imaging exoplanets with nulling interferometry using integrated-photonics
Publisher: SPIE
Date: 03-01-2020
DOI: 10.1117/12.2539790
First on-sky demonstration of an integrated-photonic nulling interferometer
Publisher: Oxford University Press (OUP)
Date: 23-11-2020
Abstract: The characterization of exoplanets is critical to understanding planet ersity and formation, their atmospheric composition, and the potential for life. This endeavour is greatly enhanced when light from the planet can be spatially separated from that of the host star. One potential method is nulling interferometry, where the contaminating starlight is removed via destructive interference. The GLINT instrument is a photonic nulling interferometer with novel capabilities that has now been demonstrated in on-sky testing. The instrument fragments the telescope pupil into sub-apertures that are injected into waveguides within a single-mode photonic chip. Here, all requisite beam splitting, routing, and recombination are performed using integrated photonic components. We describe the design, construction, and laboratory testing of our GLINT pathfinder instrument. We then demonstrate the efficacy of this method on sky at the Subaru Telescope, achieving a null-depth precision on sky of ∼10−4 and successfully determining the angular diameter of stars (via their null-depth measurements) to milliarcsecond accuracy. A statistical method for analysing such data is described, along with an outline of the next steps required to deploy this technique for cutting-edge science.
The Palomar kernel-phase experiment: testing kernel phase interferometry for ground-based astronomical observations
Publisher: Oxford University Press (OUP)
Date: 17-11-2015
Interferometric radii of bright Kepler stars with the CHARA Array: θ Cygni and 16 Cygni A and B
Publisher: Oxford University Press (OUP)
Date: 30-05-2013
DOI: 10.1093/MNRAS/STT802
SUSI: an update on instrumental developments and science
Publisher: SPIE
Date: 14-06-2006
DOI: 10.1117/12.668982
Design of optically path-length-matched, three-dimensional photonic circuits comprising uniquely routed waveguides
Publisher: The Optical Society
Date: 12-09-2012
DOI: 10.1364/AO.51.006489
A demonstration of wavefront sensing and mirror phasing from the image domain
Publisher: Oxford University Press (OUP)
Date: 08-03-2014
DOI: 10.1093/MNRAS/STU218
Very high resolution spectro-interferometry with wavefront sensing capabilities on Subaru/SCExAO using photonics
Publisher: SPIE
Date: 09-2021
DOI: 10.1117/12.2594840
The radius and mass of the subgiant star β Hyi from interferometry and asteroseismology
Publisher: Oxford University Press (OUP)
Date: 09-12-0001
Validation of the exoplanet Kepler-21b using PAVO/CHARA long-baseline interferometry
Publisher: Oxford University Press (OUP)
Date: 03-04-2012
Imaging protoplanets: observing transition disks with non-redundant masking
Publisher: SPIE
Date: 04-08-2016
DOI: 10.1117/12.2231764
Resolved isotopic energy shift and hole burning in EuCl36H2O
Publisher: Elsevier BV
Date: 1998
The planet formation imager
Publisher: Springer Science and Business Media LLC
Date: 04-07-2018
Fabrication of ultra-low bend loss optical waveguides
Publisher: IEEE
Date: 05-2013
Photonic technologies for a pupil remapping interferometer
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856770
Interferometric diameters of five evolved intermediate-mass planet-hosting stars measured with PAVO at the CHARA Array
Publisher: Oxford University Press (OUP)
Date: 18-04-2018
DOI: 10.1093/MNRAS/STY898
Infrared Observations of the Asymmetric Mass Loss of an AGB Star
Publisher: MDPI AG
Date: 12-10-2018
Abstract: We report on the observations of the circumstellar envelope of the AGB star II Lup in the near- and mid-infrared with the use of direct imaging and interferometric techniques. Our findings indicate that the circumstellar envelope is not spherically symmetric and that the majority of the emission originates within 0.5 arcsec from the star.
Performance of the Gemini Planet Imager Non-redundant Mask and Spectroscopy of Two Close-separation Binaries: HR 2690 and HD 142527
Publisher: American Astronomical Society
Date: 03-06-2019
Adaptive optics for the CHARA array
Publisher: SPIE
Date: 13-09-2012
DOI: 10.1117/12.927031
Pulsation of M-type Mira variables with moderately different mass: Search for observable mass effects
Publisher: Oxford University Press (OUP)
Date: 12-2004
Low bend loss waveguides enable compact, efficient 3D photonic chips
Publisher: The Optical Society
Date: 31-01-2013
DOI: 10.1364/OE.21.002978
MID-INFRARED SIZE SURVEY OF YOUNG STELLAR OBJECTS: DESCRIPTION OF KECK SEGMENT-TILTING EXPERIMENT AND BASIC RESULTS
Publisher: American Astronomical Society
Date: 02-07-2009
Mapping the Shores of the Brown Dwarf Desert. III. Young Moving Groups
Publisher: American Astronomical Society
Date: 20-12-2012
First on-sky demonstration of a compact fully-integrated photonic waveguide nulling interferometer
Publisher: OSA
Date: 2016
A Tale of Two Herbig Ae Stars, MWC 275 and AB Aurigae: Comprehensive Models for Spectral Energy Distribution and Interferometry
Publisher: American Astronomical Society
Date: 10-12-2008
DOI: 10.1086/592346
Sparse aperture masking (SAM) at NAOS/CONICA on the VLT
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856806
First stellar photons through an integrated photonic pupil remapping interferometer
Publisher: IEEE
Date: 08-2011
HD 181068: A Red Giant in a Triply Eclipsing Compact Hierarchical Triple System
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-04-2011
Abstract: The Kepler satellite reveals details of the oscillations patterns of an evolved star in an exotic triple-star system.
The SUSI instrument: new science and technology
Publisher: SPIE
Date: 14-07-2008
DOI: 10.1117/12.787707
Scalable photonic-based nulling interferometry with the dispersed multi-baseline GLINT instrument
Publisher: Springer Science and Business Media LLC
Date: 29-04-2021
DOI: 10.1038/S41467-021-22769-X
Abstract: Characterisation of exoplanets is key to understanding their formation, composition and potential for life. Nulling interferometry, combined with extreme adaptive optics, is among the most promising techniques to advance this goal. We present an integrated-optic nuller whose design is directly scalable to future science-ready interferometric nullers: the Guided-Light Interferometric Nulling Technology, deployed at the Subaru Telescope. It combines four beams and delivers spatial and spectral information. We demonstrate the capability of the instrument, achieving a null depth better than 10 −3 with a precision of 10 −4 for all baselines, in laboratory conditions with simulated seeing applied. On sky, the instrument delivered angular diameter measurements of stars that were 2.5 times smaller than the diffraction limit of the telescope. These successes pave the way for future design enhancements: scaling to more baselines, improved photonic component and handling low-order atmospheric aberration within the instrument, all of which will contribute to enhance sensitivity and precision.
Dust scattering in the Miras R Car and RR Sco resolved by optical interferometric polarimetry
Publisher: Oxford University Press (OUP)
Date: 07-2005
Dynamical Mass of GJ 802B: A Brown Dwarf in a Triple System
Publisher: American Astronomical Society
Date: 05-2008
DOI: 10.1086/529578
Science programs for a 2-m class telescope at dome C, antarctica: PILOT, the pathfinder for an International Large Optical Telescope
Publisher: Cambridge University Press (CUP)
Date: 2005
DOI: 10.1071/AS04077
Abstract: The cold, dry, and stable air above the summits of the Antarctic plateau provides the best ground-based observing conditions from optical to sub-millimetre wavelengths to be found on the Earth. Pathfinder for an International Large Optical Telescope (PILOT) is a proposed 2 m telescope, to be built at Dome C in Antarctica, able to exploit these conditions for conducting astronomy at optical and infrared wavelengths. While PILOT is intended as a pathfinder towards the construction of future grand-design facilities, it will also be able to undertake a range of fundamental science investigations in its own right. This paper provides the performance specifications for PILOT, including its instrumentation. It then describes the kinds of projects that it could best conduct. These range from planetary science to the search for other solar systems, from star formation within the Galaxy to the star formation history of the Universe, and from gravitational lensing caused by exo-planets to that produced by the cosmic web of dark matter. PILOT would be particularly powerful for wide-field imaging at infrared wavelengths, achieving near diffraction-limited performance with simple tip–tilt wavefront correction. PILOT would also be capable of near diffraction-limited performance in the optical wavebands, as well be able to open new wavebands for regular ground-based observation, in the mid-IR from 17 to 40 μm and in the sub-millimetre at 200 μm.
Discovery of Seven Companions to Intermediate-mass Stars with Extreme Mass Ratios in the Scorpius-Centaurus Association
Publisher: American Astronomical Society
Date: 04-06-2015
Phase retrieval and design with automatic differentiation: tutorial
Publisher: Optica Publishing Group
Date: 06-08-2021
DOI: 10.1364/JOSAB.432723
Abstract: The principal limitation in many areas of astronomy, especially for directly imaging exoplanets, arises from instability in the point spread function (PSF) delivered by the telescope and instrument. To understand the transfer function, it is often necessary to infer a set of optical aberrations given only the intensity distribution on the sensor—the problem of phase retrieval . This can be important for post-processing of existing data, or for the design of optical phase masks to engineer PSFs optimized to achieve high-contrast, angular resolution, or astrometric stability. By exploiting newly efficient and flexible technology for automatic differentiation , which in recent years has undergone rapid development driven by machine learning, we can perform both phase retrieval and design in a way that is systematic, user-friendly, fast, and effective. By using modern gradient descent techniques, this converges efficiently and is easily extended to incorporate constraints and regularization. We illustrate the wide-ranging potential for this approach using our new package, Morphine. Challenging applications performed with this code include precise phase retrieval for both discrete and continuous phase distributions, even where information has been censored such as heavily saturated sensor data. We also show that the same algorithms can optimize continuous or binary phase masks that are competitive with existing best solutions for two ex le problems: an apodizing phase plate coronagraph for exoplanet direct imaging, and a diffractive pupil for narrow-angle astrometry. The Morphine source code and ex les are available open-source, with an interface similar to the popular physical optics package Poppy.
SUSI: recent technology and science
Publisher: SPIE
Date: 20-10-2004
DOI: 10.1117/12.549483
3D Photonics in the Mid-infrared: Parametric study of ultrafast laser inscribed waveguides for stellar interferometry
Publisher: OSA
Date: 2016
A CLOSE COMPANION SEARCH AROUND L DWARFS USING APERTURE MASKING INTERFEROMETRY AND PALOMAR LASER GUIDE STAR ADAPTIVE OPTICS
Publisher: American Astronomical Society
Date: 04-05-2010
High-resolution observations of the outer disk around T Chamaeleontis: the view from ALMA
Publisher: EDP Sciences
Date: 17-02-2015
Planet formation imager: project update
Publisher: SPIE
Date: 09-07-2018
DOI: 10.1117/12.2312683
Achromatic photonic tricouplers for application in nulling interferometry
Publisher: Optica Publishing Group
Date: 17-06-2021
DOI: 10.1364/AO.423541
Abstract: Integrated-optic components are being increasingly used in astrophysics, mainly where accuracy and precision are paramount. One such emerging technology is nulling interferometry that targets high contrast and high angular resolution. Two of the most critical limitations encountered by nullers are rapid phase fluctuations in the incoming light causing instability in the interference and chromaticity of the directional couplers that prevent a deep broadband interferometric null. We explore the use of a tricoupler designed by ultrafast laser inscription that solves both issues. Simulations of a tricoupler, incorporated into a nuller, result in an order of a magnitude improvement in null depth.
Mid-infrared astrophotonics: Study of ultrafast laser induced index change in compatible materials
Publisher: The Optical Society
Date: 02-02-2017
DOI: 10.1364/OME.7.000698
Optical interferometry of early-type stars with PAVO@CHARA – I. Fundamental stellar properties
Publisher: Oxford University Press (OUP)
Date: 09-07-2013
The science case for the Planet Formation Imager (PFI)
Publisher: SPIE
Date: 24-07-2014
DOI: 10.1117/12.2055544
Precision Masses of the Low‐Mass Binary System GJ 623
Publisher: American Astronomical Society
Date: 20-05-2007
DOI: 10.1086/513868
Building hybridized 28-baseline pupil-remapping photonic interferometers for future high-resolution imaging
Publisher: Optica Publishing Group
Date: 03-05-2021
DOI: 10.1364/AO.422729
Abstract: One key advantage of single-mode photonic technologies for interferometric use is their ability to easily scale to an ever-increasing number of inputs without a major increase in the overall device size, compared to traditional bulk optics. This is particularly important for the upcoming extremely large telescope (ELT) generation of telescopes currently under construction. We demonstrate the fabrication and characterization of a hybridized photonic interferometer, with eight simultaneous inputs, forming 28 baselines, which is the largest amount to date, to the best of our knowledge. Using different photonic fabrication technologies, we combine a 3D pupil remapper with a planar eight-port ABCD pairwise beam combiner, along with the injection optics necessary for telescope use, into a single integrated monolithic device. We successfully realized a combined device called Dragonfly, which demonstrates a raw instrumental closure-phase stability down to 0.9° over 8 π phase piston error, relating to a detection contrast of ∼ 6.5 × 10 − 4 on an adaptive-optics-corrected 8 m telescope. This prototype successfully demonstrates advanced hybridization and packaging techniques necessary for on-sky use for high-contrast detection at small inner working angles, ideally complementing what can currently be achieved using coronagraphs.
Non-redundant masking ideas on JWST
Publisher: SPIE
Date: 02-08-2014
DOI: 10.1117/12.2056639
Photonic mid-infrared nulling for exoplanet detection on a planar chalcogenide platform
Publisher: SPIE
Date: 09-07-2018
DOI: 10.1117/12.2311904
Chalcogenide glass planar MIR couplers for future chip based Bracewell interferometers
Publisher: SPIE
Date: 04-08-2016
DOI: 10.1117/12.2232199
On the full holonomy group of Lorentzian manifolds
Publisher: Springer Science and Business Media LLC
Date: 25-02-2014
Imaging rapid rotators with the PAVO beam combiner at CHARA
Publisher: SPIE
Date: 12-09-2012
DOI: 10.1117/12.926881
High performance 3D waveguide architecture for astronomical pupil-remapping interferometry
Publisher: SPIE
Date: 24-07-2014
DOI: 10.1117/12.2057282
What’s in a name? Preschoolers’ noun learning performance in relation to their risk for reading disability
Publisher: Springer Science and Business Media LLC
Date: 11-12-2008
A close halo of large transparent grains around extreme red giant stars
Publisher: Springer Science and Business Media LLC
Date: 04-2012
DOI: 10.1038/NATURE10935
Abstract: An intermediate-mass star ends its life by ejecting the bulk of its envelope in a slow, dense wind. Stellar pulsations are thought to elevate gas to an altitude cool enough for the condensation of dust, which is then accelerated by radiation pressure, entraining the gas and driving the wind. Explaining the amount of mass loss, however, has been a problem because of the difficulty of observing tenuous gas and dust only tens of milliarcseconds from the star. For this reason, there is no consensus on the way sufficient momentum is transferred from the light from the star to the outflow. Here we report spatially resolved, multiwavelength observations of circumstellar dust shells of three stars on the asymptotic giant branch of the Hertzsprung-Russell diagram. When imaged in scattered light, dust shells were found at remarkably small radii (less than about two stellar radii) and with unexpectedly large grains (about 300 nanometres in radius). This proximity to the photosphere argues for dust species that are transparent to the light from the star and, therefore, resistant to sublimation by the intense radiation field. Although transparency usually implies insufficient radiative pressure to drive a wind, the radiation field can accelerate these large grains through photon scattering rather than absorption--a plausible mass loss mechanism for lower- litude pulsating stars.
Two Wolf–Rayet stars at the heart of colliding-wind binary Apep
Publisher: Oxford University Press (OUP)
Date: 2020
Abstract: Infrared imaging of the colliding-wind binary Apep has revealed a spectacular dust plume with complicated internal dynamics that challenges standard colliding-wind binary physics. Such challenges can be potentially resolved if a rapidly rotating Wolf–Rayet star is located at the heart of the system, implicating Apep as a Galactic progenitor system to long-duration gamma-ray bursts. One of the difficulties in interpreting the dynamics of Apep is that the spectral composition of the stars in the system was unclear. Here, we present visual to near-infrared spectra that demonstrate that the central component of Apep is composed of two classical Wolf–Rayet stars of carbon- (WC8) and nitrogen-sequence (WN4-6b) subtypes. We argue that such an assignment represents the strongest case of a classical Wolf–Rayet+Wolf–Rayet binary system in the Milky Way. The terminal line-of-sight wind velocities of the WC8 and WN4-6b stars are measured to be 2100 ± 200 and 3500 ± 100 km s−1, respectively. If the mass-loss rate of the two stars are typical for their spectral class, the momentum ratio of the colliding winds is expected to be ≈0.4. Since the expansion velocity of the dust plume is significantly smaller than either of the measured terminal velocities, we explore the suggestion that one of the Wolf–Rayet winds is anisotropic. We can recover a shock-compressed wind velocity consistent with the observed dust expansion velocity if the WC8 star produces a significantly slow equatorial wind with a velocity of ≈530 km s−1. Such slow wind speeds can be driven by near-critical rotation of a Wolf–Rayet star.
The Angular Diameter and Fundamental Parameters of Sirius A
Publisher: Cambridge University Press (CUP)
Date: 2011
DOI: 10.1071/AS10010
Abstract: The Sydney University Stellar Interferometer (SUSI) has been used to make a new determination of the angular diameter of Sirius A. The observations were made at an effective wavelength of 694.1 nm and the new value for the limb-darkened angular diameter is 6.048 ± 0.040 mas (± 0.66%). This new result is compared with previous measurements and is found to be in excellent agreement with a conventionally calibrated measurement made with the European Southern Observatory's Very Large Telescope Interferometer (VLTI) at 2.176 μm (but not with a second globally calibrated VLTI measurement). A weighted mean of the SUSI and first VLTI results gives the limb-darkened angular diameter of Sirius A as 6.041 ± 0.017 mas (± 0.28%). Combination with the Hipparcos parallax gives the radius equal to 1.713 ± 0.009 R ⊙ . The bolometric flux has been determined from published photometry and spectrophotometry and, combined with the angular diameter, yields the emergent flux at the stellar surface equal to (5.32 ± 0.14) × 10 8 W m −2 and the effective temperature equal to 9845 ± 64 K. The luminosity is 24.7 ± 0.7 L ⊙ .
The Asymmetric Dust Environment of IK Tauri
Publisher: American Astronomical Society
Date: 10-01-2006
DOI: 10.1086/498062
The weather report from IRC+10216: evolving irregular clouds envelop carbon star
Publisher: Oxford University Press (OUP)
Date: 03-12-2015
Orbital elements, masses and distance of Scorpii A and B determined with the Sydney University Stellar Interferometer and high-resolution spectroscopy
Publisher: Oxford University Press (OUP)
Date: 08-2006
Probing dusty circumstellar environments with polarimetric aperture-masking interferometry
Publisher: SPIE
Date: 12-09-2012
DOI: 10.1117/12.925838
The AST3-NIR camera for the Kunlun Infrared Sky Survey
Publisher: SPIE
Date: 09-08-2016
DOI: 10.1117/12.2233317
Learning the lantern: neural network applications to broadband photonic lantern modeling
Publisher: SPIE-Intl Soc Optical Eng
Date: 29-06-2021
SCExAO, an instrument with a dual purpose: perform cutting-edge science and develop new technologies
Publisher: SPIE
Date: 13-07-2018
DOI: 10.1117/12.2314282
THE KECK APERTURE MASKING EXPERIMENT: SPECTRO-INTERFEROMETRY OF THREE MIRA VARIABLES FROM 1.1 TO 3.8 μm
Publisher: American Astronomical Society
Date: 02-2009
Low bend loss waveguides and photonic bandgaps enabled by high index contrast modifications
Publisher: EDP Sciences
Date: 2013
Progress and challenges with the Dragonfly instrument; An integrated-photonic pupil-remapping interferometer
Publisher: SPIE
Date: 12-09-2012
DOI: 10.1117/12.926012
Discovery of a Circumbinary Disk around Herbig Ae/Be System V892 Tauri
Publisher: American Astronomical Society
Date: 25-06-2008
DOI: 10.1086/590532
Starlight demonstration of the Dragonfly instrument: An integrated photonic pupil-remapping interferometer for high-contrast imaging
Publisher: Oxford University Press (OUP)
Date: 02-11-2012
Photonic ring resonator filters for astronomical OH suppression
Publisher: The Optical Society
Date: 27-06-2017
DOI: 10.1364/OE.25.015868
Modal noise in an integrated photonic lantern fed diffraction-limited spectrograph
Publisher: The Optical Society
Date: 06-10-2017
DOI: 10.1364/OE.25.025546
Non-redundant Aperture Masking Interferometry (AMI) and segment phasing with JWST-NIRISS
Publisher: SPIE
Date: 22-08-2012
DOI: 10.1117/12.925565
The keck aperture masking experiment: Multiwavelength observations of six Mira variables
Publisher: American Astronomical Society
Date: 08-01-2014
DOI: 10.1086/523936
Beyond the Kepler/K2 bright limit: Variability in the seven brightest members of the Pleiades
Publisher: Oxford University Press (OUP)
Date: 11-08-2017
High contrast imaging at the photon noise limit with self-calibrating WFS/C systems
Publisher: SPIE
Date: 09-2021
DOI: 10.1117/12.2594885
The Emergent Flux and Effective Temperature of δ Canis Majoris
Publisher: Cambridge University Press (CUP)
Date: 2007
DOI: 10.1071/AS07017
Abstract: New angular diameter determinations for the bright southern F8 supergiant δ CMa enable the bolometric emergent flux and effective temperature of the star to be determined with improved accuracy. The spectral flux distribution and bolometric flux have been determined from published photometry and spectrophotometry and combined with the angular diameter to derive the bolometric emergent flux ℱ = (6.50 ± 0.24) × 10 7 Wm −2 and the effective temperature T eff = 5818 ± 53 K. The new value for the effective temperature is compared with previous interferometric and infrared flux method determinations. The accuracy of the effective temperature is now limited by the uncertainty in the bolometric flux rather than by the uncertainty in the angular diameter.
The Sydney University Stellar Interferometer: A Major Upgrade to Spectral Coverage and Performance
Publisher: Cambridge University Press (CUP)
Date: 2007
DOI: 10.1071/AS07016
Abstract: A new beam-combination and detection system has been installed in the Sydney University Stellar Interferometer working at the red end of the visual spectrum (λλ 500–950 nm) to complement the existing blue-sensitive system (λλ 430–520 nm) and to provide an increase in sensitivity. Dichroic beam-splitters have been introduced to allow simultaneous observations with both spectral systems, albeit with some restriction on the spectral range of the longer wavelength system (λλ 550–760 nm). The blue system has been upgraded to allow remote selection of wavelength and spectral bandpass, and to enable simultaneous operation with the red system with the latter providing fringe-envelope tracking. The new system and upgrades are described and ex les of commissioning tests presented. As an illustration of the improvement in performance the measurement of the angular diameter of the southern F supergiant δ CMa is described and compared with previous determinations.
High-performance 3D waveguide architecture for astronomical pupil-remapping interferometry
Publisher: The Optical Society
Date: 22-07-2201
DOI: 10.1364/OE.22.018335
Improved performance characteristics for the integrated photonic pupil remapping interferometer dragonfly
Publisher: IEEE
Date: 05-2013
Low-cost scheme for high-precision dual-wavelength laser metrology
Publisher: The Optical Society
Date: 17-04-2013
DOI: 10.1364/AO.52.002808
Cepheid Observations with the Sydney University Stellar Interferometer: ℓCarinae and βDoradus
Publisher: Springer Berlin Heidelberg
Date: 2008
The radius and other fundamental parameters of the F9 v star β Virginis
Publisher: Oxford University Press (OUP)
Date: 11-02-2009
The James Webb Space Telescope aperture masking interferometer
Publisher: SPIE
Date: 14-12-2020
DOI: 10.1117/12.2560804
Planet formation imager (PFI): introduction and technical considerations
Publisher: SPIE
Date: 24-07-2014
DOI: 10.1117/12.2057262
VISUAL ORBIT OF THE LOW-MASS BINARY GJ 164 AB
Publisher: American Astronomical Society
Date: 07-04-2009
A companion candidate in the gap of the T Chamaeleontis transitional disk
Publisher: EDP Sciences
Date: 24-02-2011
Masses of Astrometrically Discovered and Imaged Binaries: G78‐28AB and GJ 231.1BC
Publisher: American Astronomical Society
Date: 20-09-2006
DOI: 10.1086/506192
Resolving Decades of Periodic Spirals from the Wolf–Rayet Dust Factory WR 112
Publisher: American Astronomical Society
Date: 15-09-2020
Simulating a dual beam combiner at SUSI for narrow-angle astrometry
Publisher: Springer Science and Business Media LLC
Date: 14-03-2013
Accreting protoplanets in the LkCa 15 transition disk
Publisher: Springer Science and Business Media LLC
Date: 11-2015
DOI: 10.1038/NATURE15761
Abstract: Exoplanet detections have revolutionized astronomy, offering new insights into solar system architecture and planet demographics. While nearly 1,900 exoplanets have now been discovered and confirmed, none are still in the process of formation. Transition disks, protoplanetary disks with inner clearings best explained by the influence of accreting planets, are natural laboratories for the study of planet formation. Some transition disks show evidence for the presence of young planets in the form of disk asymmetries or infrared sources detected within their clearings, as in the case of LkCa 15 (refs 8, 9). Attempts to observe directly signatures of accretion onto protoplanets have hitherto proven unsuccessful. Here we report adaptive optics observations of LkCa 15 that probe within the disk clearing. With accurate source positions over multiple epochs spanning 2009-2015, we infer the presence of multiple companions on Keplerian orbits. We directly detect Hα emission from the innermost companion, LkCa 15 b, evincing hot (about 10,000 kelvin) gas falling deep into the potential well of an accreting protoplanet.
Direct Detection of the Brown Dwarf GJ 802B with Adaptive Optics Masking Interferometry
Publisher: American Astronomical Society
Date: 10-10-2006
DOI: 10.1086/508771
Sensitive visible interferometry with PAVO
Publisher: SPIE
Date: 14-07-2008
DOI: 10.1117/12.788386
GLINT South: A photonic nulling interferometer pathfinder at the Anglo-Australian Telescope for high contrast imaging of substellar companions
Publisher: SPIE
Date: 09-07-2018
DOI: 10.1117/12.2313171
Status of the SCExAO instrument: recent technology upgrades and path to a system-level demonstrator for PSI
Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2562832
The expanding fireball of Nova Delphini 2013
Publisher: Springer Science and Business Media LLC
Date: 26-10-2014
DOI: 10.1038/NATURE13834
Abstract: A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common-envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 ± 0.59 kiloparsecs from the Sun.
Kernel Phase and Coronagraphy with Automatic Differentiation
Publisher: American Astronomical Society
Date: 2021
Abstract: The accumulation of aberrations along the optical path in a telescope produces distortions and speckles in the resulting images, limiting the performance of cameras at high angular resolution. It is important to achieve the highest possible sensitivity to faint sources, using both hardware and data analysis software. While analytic methods are efficient, real systems are better modeled numerically, but numerical models of complicated optical systems with many parameters can be hard to understand, optimize, and apply. Automatic differentiation or “backpropagation” software developed for machine-learning applications now makes calculating derivatives with respect to aberrations in arbitrary planes straightforward for any optical system. We apply this powerful new tool to the problem of high-angular-resolution astronomical imaging. Self-calibrating observables such as the “closure phase” or “bispectrum” have been widely used in optical and radio astronomy to mitigate optical aberrations and achieve high-fidelity imagery. Kernel phases are a generalization of closure phases valid in the limit of small phase errors. Using automatic differentiation, we reproduce existing kernel phase theory within this framework and demonstrate an extension to the case of a Lyot coronagraph, which is found to have self-calibrating combinations of speckles. which are resistant to phase noise, but only in the very high-wave-front-quality regime. As an illustrative ex le, we reanalyze Palomar adaptive optics observations of the binary α Ophiuchi, finding consistency between the new pipeline and the existing standard. We present a new Python package morphine that incorporates these ideas, with an interface similar to the popular package poppy , for optical simulation with automatic differentiation. These methods may be useful for designing improved astronomical optical systems by gradient descent.
THE USE OF SPATIAL FILTERING WITH APERTURE MASKING INTERFEROMETRY AND ADAPTIVE OPTICS
Publisher: American Astronomical Society
Date: 09-08-2012
Ultrafast laser inscribed 3D integrated photonics
Publisher: SPIE
Date: 19-12-2027
DOI: 10.1117/12.2025535
Instrumental developments for the Sydney University Stellar Interferometer
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.856557
SPARSE APERTURE MASKING OBSERVATIONS OF THE FL Cha PRE-TRANSITIONAL DISK
Publisher: American Astronomical Society
Date: 12-12-2012
Anisotropic winds in a Wolf–Rayet binary identify a potential gamma-ray burst progenitor
Publisher: Springer Science and Business Media LLC
Date: 19-11-2018
Observations of the pulsation of the Cepheid ℓ Car with the Sydney University Stellar Interferometer
Publisher: Oxford University Press (OUP)
Date: 11-04-2009
Review and scientific prospects of high-contrast optical stellar interferometry
Publisher: SPIE
Date: 13-12-2020
DOI: 10.1117/12.2561505
The curious case of II Lup: a complex morphology revealed with SAM/NACO and ALMA
Publisher: Oxford University Press (OUP)
Date: 19-07-2018
Challenges in photonic pupil remapping for optical stellar interferometry
Publisher: IEEE
Date: 08-2011
Born‐Again Protoplanetary Disk around Mira B
Publisher: American Astronomical Society
Date: 10-06-2007
DOI: 10.1086/517993
Double-Fourier spatio-spectral decoding
Publisher: SPIE
Date: 14-06-2006
DOI: 10.1117/12.672277
DANCING IN THE DARK: NEW BROWN DWARF BINARIES FROM KERNEL PHASE INTERFEROMETRY
Publisher: American Astronomical Society
Date: 02-04-2013
Planet Formation Imager (PFI): science vision and key requirements
Publisher: SPIE
Date: 04-08-2016
DOI: 10.1117/12.2231067
GLINT
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C7G_2
Abstract: Imaging exoplanets requires high angular resolution and high contrast capability. Nulling interferometry with integrated-photonics technology can address these challenges. This paper presents GLINT, a nulling interferometer based on photonic technologies and its first on-sky results.
Sparse aperture masking at the VLT
Publisher: EDP Sciences
Date: 25-07-2011
Image-plane fringe tracker for adaptive-optics assisted long baseline interferometry
Publisher: SPIE
Date: 09-07-2018
DOI: 10.1117/12.2314393
Planetary system and star formation science with non-redundant masking on JWST
Publisher: SPIE
Date: 20-08-2009
DOI: 10.1117/12.826633
Techniques for designing physically path-length matched optical circuitry
Publisher: IEEE
Date: 08-2011
Astrophotonics: the application of photonic technology to astronomy
Publisher: SPIE
Date: 17-05-2017
DOI: 10.1117/12.2265958
The radius and effective temperature of the binary Ap star β CrB from CHARA/FLUOR and VLT/NACO observations
Publisher: EDP Sciences
Date: 03-2010
Efficiently feeding single-mode fiber photonic spectrographs with an extreme adaptive optics system
Publisher: SPIE
Date: 03-08-2016
DOI: 10.1117/12.2234299
Demonstration of an efficient, photonic-based astronomical spectrograph on an 8-m telescope
Publisher: The Optical Society
Date: 17-07-2017
DOI: 10.1364/OE.25.017753
The SCExAO high contrast imager: Transitioning from commissioning to science
Publisher: SPIE
Date: 26-07-2016
DOI: 10.1117/12.2234294
Mid‐Infrared Interferometry of Dust around Massive Evolved Stars
Publisher: American Astronomical Society
Date: 20-12-2007
DOI: 10.1086/522515
Prospects for integrated photonics in space applications
Publisher: IEEE
Date: 08-2011
Two Rings and a Marginally Resolved, 5 au Disk around LkCa 15 Identified via Near-infrared Sparse Aperture Masking Interferometry
Publisher: American Astronomical Society
Date: 05-2022
Abstract: Sparse aperture masking interferometry (SAM) is a high-resolution observing technique that allows for imaging at and beyond a telescope’s diffraction limit. The technique is ideal for searching for stellar companions at small separations from their host star however, previous analyses of SAM observations of young stars surrounded by dusty disks have had difficulties disentangling planet and extended disk emission. We analyze VLT/SPHERE-IRDIS SAM observations of the transition disk LkCa 15, model the extended disk emission, probe for planets at small separations, and improve contrast limits for planets. We fit geometrical models directly to the interferometric observables and recover previously observed extended disk emission. We use dynamic nested s ling to estimate uncertainties on our model parameters and to calculate evidences to perform model comparison. We compare our extended disk emission models against point-source models to robustly conclude that the system is dominated by extended emission within 50 au. We report detections of two previously observed asymmetric rings at ∼17 and ∼45 au. The peak brightness location of each model ring is consistent with the previous observations. We also, for the first time with imaging, robustly recover an elliptical Gaussian inner disk, previously inferred via SED fitting. This inner disk has an FWHM of 5 au and a similar inclination and orientation to the outer rings. Finally, we recover no clear evidence for candidate planets. By modeling the extended disk emission, we are able to place a lower limit on the near-infrared companion contrast of at least 1000.
Low-loss photonic nulling interferometer in the mid-infrared for astronomical applications
Publisher: OSA
Date: 2017
The fundamental parameters of the roAp star α Circini
Publisher: Oxford University Press (OUP)
Date: 30-04-2008
DOI: 10.1111/J.1365-2966.2008.13167.X
Abstract: We have used the Sydney University Stellar Interferometer to measure the angular diameter of α Cir. This is the first detailed interferometric study of a rapidly oscillating A (roAp) star, α Cir being the brightest member of its class. We used the new and more accurate Hipparcos parallax to determine the radius to be 1.967 ± 0.066 R⊙. We have constrained the bolometric flux from calibrated spectra to determine an effective temperature of 7420 ± 170 K. This is the first direct determination of the temperature of an roAp star. Our temperature is at the low end of previous estimates, which span over 1000 K and were based on either photometric indices or spectroscopic methods. In addition, we have analysed two high-quality spectra of α Cir, obtained at different rotational phases and we find evidence for the presence of spots. In both spectra we find nearly solar abundances of C, O, Si, Ca and Fe, high abundance of Cr and Mn, while Co, Y, Nd and Eu are overabundant by about 1 dex. The results reported here provide important observational constraints for future studies of the atmospheric structure and pulsation of α Cir.
AU-scale radio imaging of the wind collision region in the brightest and most luminous non-thermal colliding wind binary Apep
Publisher: Oxford University Press (OUP)
Date: 16-12-2020
Abstract: The recently discovered colliding-wind binary (CWB) Apep has been shown to emit luminously from radio to X-rays, with the emission driven by a binary composed of two Wolf–Rayet (WR) stars of one carbon-sequence (WC8) and one nitrogen-sequence (WN4–6b). Mid-infrared imaging revealed a giant spiral dust plume that is reminiscent of a pinwheel nebula but with additional features that suggest Apep is a unique system. We have conducted observations with the Australian Long Baseline Array to resolve Apep’s radio emission on milliarcsecond scales, allowing us to relate the geometry of the wind-collision region to that of the spiral plume. The observed radio emission shows a bow-shaped structure, confirming its origin as a wind-collision region. The shape and orientation of this region is consistent with being originated by the two stars and with being likely dominated by the stronger wind of the WN4–6b star. This shape allowed us to provide a rough estimation of the opening angle of ∼150○ assuming ideal conditions. The orientation and opening angle of the emission also confirms it as the basis for the spiral dust plume. We also provide estimations for the two stars in the system to milliarcsecond precision. The observed radio emission, one order of magnitude brighter and more luminous than any other known non-thermal radio-emitting CWB, confirms it is produced by an extremely powerful wind collision. Such a powerful wind-collision region is consistent with Apep being a binary composed of two WR stars, so far the first unambiguously confirmed system of its kind.
Self-phase-referencing interferometry with SUSI
Publisher: SPIE
Date: 12-09-2012
DOI: 10.1117/12.925238
CHARA array adaptive optics II: non-common-path correction and downstream optics
Publisher: SPIE
Date: 07-08-2014
DOI: 10.1117/12.2056662
Planetary system and star formation science with non-redundant masking on JWST
Publisher: SPIE
Date: 16-07-2010
DOI: 10.1117/12.858161
Multiwavelength diameters of nearby Miras and semiregular variables
Publisher: Oxford University Press (OUP)
Date: 05-2004
Efficient coupling of starlight into single mode photonics using Adaptive Injection (AI)
Publisher: SPIE
Date: 09-08-2016
DOI: 10.1117/12.2233757
Dragonfly: On-chip pupil remapping for optical stellar interferometry
Publisher: IEEE
Date: 05-2011
2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments
Publisher: IOP Publishing
Date: 10-2023
Abstract: Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular ex le to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8-m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, plus integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, beam combiners enabling long baseline interferometry with for ex le, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of 1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc., 2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and 3) efficient integration of photonics with detectors. In this roadmap, we identify 23 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.
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