Aperture Masking Imaging

Ireland, Michael

doi:10.1007/978-3-319-39739-9_3

Cited by 5 publications

(5 citation statements)

References 17 publications

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“…The same holds for the kernel phase, which is a generalization of the closure phase (e.g. Ireland 2016). Practically however, one is limited by systematic errors caused by third order phase residuals (e.g.…”

Section: Kernel Phase Calibrationmentioning

confidence: 88%

“…In the Fourier transform of the detector image (hereafter referred to as Fourier plane), these sub-apertures map onto their auto-correlation (i.e. their spatial frequencies, Ireland 2016). The phase φ of each spatial frequency can be extracted and linearly combined in a way such that the resulting closure phase θ = K · φ is independent of the pupil plane (or instrumental) phase ϕ to second order (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…terms of first and second order in ϕ are vanishing), where the matrix K encodes this special linear combination (e.g. Ireland 2016). For observations from the ground, the pupil plane phase ϕ is affected by noise from atmospheric seeing and non-common path aberrations which ultimately cause quasi-static speckles.…”

Section: Introductionmentioning

confidence: 99%

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Kernel phase imaging with VLT/NACO: high-contrast detection of new candidate low-mass stellar companions at the diffraction limit

Kammerer

Ireland

Martinache

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Directly imaging exoplanets is challenging because quasi-static phase aberrations in the pupil plane (speckles) can mimic the signal of a companion at small angular separations. Kernel phase, which is a generalization of closure phase (known from sparse aperture masking), is independent of pupil plane phase noise to second order and allows for a robust calibration of full pupil, extreme adaptive optics observations. We applied kernel phase combined with a principal component based calibration process to a suitable but not optimal, high cadence, pupil stabilized L' band (3.8 µm) data set from the ESO archive. We detect eight low-mass companions, five of which were previously unknown, and two have angular separations of ∼ 0.8-1.2 λ/D (i.e. ∼ 80-110 mas), demonstrating that kernel phase achieves a resolution below the classical diffraction limit of a telescope. While we reach a 5σ contrast limit of ∼ 1/100 at such angular separations, we demonstrate that an optimized observing strategy with more diversity of PSF references (e.g. star-hopping sequences) would have led to a better calibration and even better performance. As such, kernel phase is a promising technique for achieving the best possible resolution with future space-based telescopes (e.g. JWST), which are limited by the mirror size rather than atmospheric turbulence, and with a dedicated calibration process also for extreme adaptive optics facilities from the ground.

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Section: Kernel Phase Calibrationmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Kernel phase imaging with VLT/NACO: high-contrast detection of new candidate low-mass stellar companions at the diffraction limit

Kammerer

Ireland

Martinache

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…AMI employs a non-redundant pupil plane mask to turn the telescope primary mirror into a sparse interferometric array [17] while KPI considers interference between all parts of the full pupil [18]. These techniques typically achieve contrasts of < 10 mag, but enable detections at small angular separations down to ∼ 0.5 λ/D, well inside the IWA of classical coronagraphs [19,20]. In this work, we aim to compare the performance of several JWST high-contrast imaging techniques in the 3-5 µm regime, where JWST is expected to reach its best IWA.…”

Section: Introductionmentioning

confidence: 99%

Performance of near-infrared high-contrast imaging methods with JWST from commissioning

Kammerer¹,

Girard²,

Carter³

et al. 2022

Preprint

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The James Webb Space Telescope (JWST ) will revolutionize the field of high-contrast imaging and enable both the direct detection of Saturn-mass planets and the characterization of substellar companions in the mid-infrared. While JWST will feature unprecedented sensitivity, angular resolution will be the key factor when competing with ground-based telescopes. Here, we aim to characterize the performance of several extreme angular resolution imaging techniques available with JWST in the 3-5 µm regime based on data taken during the instrument commissioning. Firstly, we introduce custom tools to simulate, reduce, and analyze JWST NIRCam and MIRI coronagraphy data and use these tools to extract companion detection limits from on-sky NIRCam round and bar mask coronagraphy observations. Secondly, we present on-sky JWST NIRISS aperture masking interferometry (AMI) and kernel phase imaging (KPI) observations from which we extract companion detection limits using the publicly available fouriever tool. Scaled to a total integration time of one hour and a target of the brightness of AB Dor (W1 ≈ 4.4 mag, W2 ≈ 3.9 mag), we find that NIRISS AMI and KPI reach contrasts of ∼ 7-8 mag at ∼ 70 mas and ∼ 9 mag at ∼ 200 mas. Beyond ∼ 250 mas, NIRCam coronagraphy reaches deeper contrasts of ∼ 13 mag at ∼ 500 mas and ∼ 15 mag at ∼ 2 arcsec. While the bar mask performs ∼ 1 mag better than the round mask at small angular separations 0.75 arcsec, it is the other way around at large angular separations 1.5 arcsec. Moreover, the round mask gives access to the full 360 deg field-of-view which is beneficial for the search of new companions. We conclude that already during the instrument commissioning, JWST high-contrast imaging in the L-and M-bands performs close to its predicted limits and is a factor of ∼ 10 times better at large separations than the best ground-based instruments operating at similar wavelengths despite its > 2 times smaller collecting area.

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“…The first speckle interferometry techniques only recovered auto-correlation maps [67], but further studies yielded to the recovery of true diffraction-limited images with the help of aperture masks [68]. This latter technique, generally referred to as aperture masking, is still providing results in astronomical research despite its age [69]. The fact of blocking part of the incoming light, however, means that only relatively bright stars can be observed.…”

Section: Speckle Interferometrymentioning

confidence: 99%

Contribuciones a tecnología y técnicas para astronomía terrestre y espacial síntesis de codecs EDAC, AOLI y COELI

Conde¹

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In no particular order, I would like to dedicate this thesis to: my mother, for her loving support in these times of hard work; my father, for his useful advice all along the elaboration of this thesis; my sister, for being my particular guide star in a wide range of targets; my brother, for caring about my work though sometimes pretending not to; the mother of the killer whale, for filling my everyday life with love and joy; my friends, for giving me the energy and enthusiasm that keep me moving forward; my work colleagues, for all the misfortunes and successes we have shared together; and lastly, to my supervisors, for having let me participate in such incredible projects, opening a wide path for me to keep working in all the things I like the most. Your tutoring during these years has truly made me grow as a researcher, as an engineer, and more importantly, as a person. 1. C. Colodro-Conde and R. Toledo-Moreo. "Design and analysis of efficient synthesis algorithms for EDAC functions in FPGAs". In: IEEE Transactions on Aerospace and Electronic Systems 51.4 (Oct. 2015), pp. 3332-3347.

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Aperture Masking Imaging

Cited by 5 publications

References 17 publications

Kernel phase imaging with VLT/NACO: high-contrast detection of new candidate low-mass stellar companions at the diffraction limit

Kernel phase imaging with VLT/NACO: high-contrast detection of new candidate low-mass stellar companions at the diffraction limit

Performance of near-infrared high-contrast imaging methods with JWST from commissioning

Contribuciones a tecnología y técnicas para astronomía terrestre y espacial síntesis de codecs EDAC, AOLI y COELI

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