Aperture Masking Interferometry used in combination with Adaptive Optics, is a powerful technique that permits the detection of faint companions at small angular separations. The precision calibration of the data achieved with this observing mode indeed leads to reliable results up to and beyond the formal diffraction limit, explaining why it has, in just a few years, been ported on most major telescopes. In this poster, we present its possible implementation on Subaru. We also discuss how the opportunity offered by the planned Extreme-AO upgrade to HiCIAO will push further the performance of this already successful technique, offering Subaru a unique access to a very exciting region of the "contrast-ratio - angular separation" parameter space.
Low wind and petaling effects, caused by the discontinuous apertures of telescopes, are poorly corrected -- if at all -- by commonly used workhorse wavefront sensors (WFSs). Wavefront petaling breaks the coherence of the point spread function core, splitting it into several side lobes, dramatically shutting off scientific throughput. We demonstrate the re-purposing of non-redundant sparse aperture masking (SAM) interferometers into low-order WFSs complementing the high-order pyramid WFS, on the SCExAO experimental platform at Subaru Telescope. The SAM far-field interferograms formed from a 7-h…
JWST's Near-Infrared Imager and Slitless Spectrograph (NIRISS) includes an Aperture Masking Interferometry (AMI) mode designed to be used between 2.7μm and 4.8μm. At these wavelengths, it will have the highest angular resolution of any mode on JWST, and, for faint targets, of any existing or planned infrastructure. NIRISS AMI is uniquely suited to detect thermal emission of young massive planets and will permit the characterization of the mid-IR flux of exoplanets discovered by the GPI and SPHERE adaptive optics surveys. It will also directly detect massive planets found by GAIA through astrom…
The exquisite precision delivered by interferometric techniques is rapidly being applied to more and more branches of optical astronomy. One particularly successful strategy to obtain structures at the scale of the diffraction limit is Aperture Masking Interferometry, which is presently experience a golden age with implementations at a host of large telescopes around the world. This startlingly durable technique, which turns 144 years old this year, presently sets the standard for the recovery of faint companions within a few resolution elements from the core of a stellar point spread function…
Radio interferometry is the current method of choice for deep space astronomy, but in the past few decades optical techniques have become increasingly common. This research seeks to characterize the performance of aperture masking interferometry in the near-infrared at small scales. A mask containing six pairs of apertures at varying diameters and separations was constructed for use with a 24-inch telescope at the MIT Wallace Astrophysical Observatory. Test images of Spica and Jupiter were captured for 28 different telescope configurations, varying aperture separation, aperture diameter, colle…
Single-aperture spectro-interferometry in the visible at the Subaru telescope with FIRST: First on-sky demonstration on Keho'oea (α Lyrae) and Hokulei (α Aurigae)
The new operational mode of aperture masking interferometry has been added to the CONICA camera which lies downstream of the Adaptive Optics (AO) corrected focus provided by NAOS on the VLT-UT4 telescope. Masking has been shown to deliver superior PSF calibration, rejection of atmospheric noise and robust recovery of phase information through the use of closure phases. Over the resolution range from about half to several resolution elements, masking interferometry is presently unsurpassed in delivering high fidelity imaging and direct detection of faint companions. Here we present results from…
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 \micron~wavelengths, and a bright limit of $\simeq 4$ magnitudes in W2. We describe the NIRISS Aperture Masking Interferometry (AMI) mode to help potential observers understand its underlying principles, present some sample 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 re…
At present, the principal limitation on the resolution and contrast of astronomical imaging instruments comes from aberrations in the optical path, which may be imposed by the Earth's turbulent atmosphere or by variations in the alignment and shape of the telescope optics. These errors can be corrected physically, with active and adaptive optics, and in post-processing of the resulting image. A recently-developed adaptive optics post-processing technique, called kernel phase interferometry, uses linear combinations of phases that are self-calibrating with respect to small errors, with the goal…
We present a close companion search around sixteen known early-L dwarfs using aperture masking interferometry with Palomar laser guide star adaptive optics. The use of aperture masking allows the detection of close binaries, corresponding to projected physical separations of 0.6-10.0 AU for the targets of our survey. This survey achieved median contrast limits of Delta_K ~ 2.3 for separations between 1.2 - 4 lambda/D, and Delta_K ~ 1.4 at (2/3)lambda/D. We present four candidate binaries detected with moderate to high confidence (90-98%). Two have projected physical separations less than 1.5 A…
Due to feedback from accretion onto supermassive black holes (SMBHs), Active Galactic Nuclei (AGNs) are believed to play a key role in LambdaCDM cosmology and galaxy formation. However, AGNs' extreme luminosities and the small angular size of their accretion flows create a challenging imaging problem. We show James Webb Space Telescope's Near Infrared Imager and Slitless Spectrograph (JWST-NIRISS) Aperture Masking Interferometry (AMI) mode will enable true imaging (i.e. without any requirement of prior assumptions on source geometry) at ~65 mas angular resolution at the centers of AGNs. This i…
Spectrally dispersed non-redundant aperture-masking interferometry in the thermal infrared with LBTI/ALES
The University of Arizona（亚利桑那大学）；University of Wyoming（怀俄明大学）；KU Leuven（荷语鲁汶大学）；Macquarie University（麦考瑞大学）；Large Binocular Telescope Observatory, The University of Arizona（大型双筒望远镜天文台，亚利桑那大学）
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 analysis of SAM observations of young stars surrounded by dusty disks have had difficulties disentangling planet and extended disk emission. We analyse 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 f…
We present the earliest results of our NACO/VLT sparse aperture masking (SAM) campaign to search for binarity in a sample of 60 O-type stars. We detect Delta Ks < 5 mag companions for 20-25% of our targets with separations in the range 30-100 mas (typically, 40 - 200 A.U.). Most of these companions were unknown, shedding thus new light on the multiplicity properties of massive stars in a separation and brightness regime that has been difficult to explore so far. Adding detections from other techniques (spectroscopy, interferometry, speckle, lucky imaging, AO), the fraction of O stars with at l…
The detection and characterisation of extra-solar planets is a major theme driving modern astronomy, with the vast majority of such measurements being achieved by Doppler radial-velocity and transit observations. Another technique -- direct imaging -- can access a parameter space that complements these methods, and paves the way for future technologies capable of detailed characterization of exoplanetary atmospheres and surfaces. However achieving the required levels of performance with direct imaging, particularly from ground-based telescopes which must contend with the Earth's turbulent atmo…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IV: NIRISS Aperture Masking Interferometry Performance and Lessons Learned
Filling out the dearth of detections between direct imaging and radial velocity surveys will test theories of planet formation and (sub)stellar binarity across the full range of semi-major axes, connecting formation of close to wide separation gas giants and substellar companions. Direct detection of close-in companions is notoriously difficult: coronagraphs and point spread function (PSF) subtraction techniques fail near the $λ/D$ diffraction limit. We present a new faint companion detection pipeline called Argus which analyzes kernel phases, an interferometric observable analogous to closure…
The detection of high contrast companions at small angular separation appears feasible in conventional direct images using the self-calibration properties of interferometric observable quantities. The friendly notion of closure-phase, which is key to the recent observational successes of non-redundant aperture masking interferometry used with Adaptive Optics, appears to be one example of a wide family of observable quantities that are not contaminated by phase-noise. In the high-Strehl regime, soon to be available thanks to the coming generation of extreme Adaptive Optics systems on ground bas…
To reach its optimal performance, Fizeau interferometry requires that we work to resolve instrumental biases through calibration. One common technique used in high contrast imaging is angular differential imaging, which calibrates the point spread function and flux leakage using a rotation in the focal plane. Our aim is to experimentally demonstrate and validate the efficacy of an angular differential kernel-phase approach, a new method for self-calibrating interferometric observables that operates similarly to angular differential imaging, while retaining their statistical properties. We used…
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems III: Aperture Masking Interferometric Observations of the star HIP 65426 at 3.8 um
