A5009977996- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Optical Systems and Laser Technology
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Calibration and Measurement Techniques
- Advanced optical system design
- Astro and Planetary Science
- Optical Coherence Tomography Applications
- Optical Wireless Communication Technologies
- Solid State Laser Technologies
- Metallurgical Processes and Thermodynamics
- Advanced Fiber Optic Sensors
- Geophysics and Sensor Technology
- Atmospheric Ozone and Climate
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Magnetic confinement fusion research
- Electric Motor Design and Analysis
- Gamma-ray bursts and supernovae
- Recommender Systems and Techniques
- Optical Coatings and Gratings
- Scientific Research and Discoveries
- Advanced Measurement and Metrology Techniques
MIT Lincoln Laboratory
2023
Center for Astrophysics Harvard & Smithsonian
2015-2022
Harvard University Press
2017-2019
University of Arizona
2008-2014
Max Planck Institute for Astronomy
2013-2014
Cornell University
2003-2004
Fusion Academy
2003
Plasma Technology (United States)
2003
The intermittent turbulent transport in the scrape-off-layer (SOL) of Alcator C-Mod [I.H. Hutchinson, R. Boivin, P.T. Bonoli et al., Nucl. Fusion 41, 1391 (2001)] is studied experimentally by imaging with a very high density spatial measurements. two-dimensional structure and dynamics emission from localized gas puff are observed, features (also sometimes called “filaments” or “blobs”) typically seen. characteristics turbulence their relationship to time-averaged SOL profiles discussed...
Young giant exoplanets are a unique laboratory for understanding cool, low-gravity atmospheres. A quintessential example is the massive extrasolar planet $β$ Pic b, which 9 AU from and embedded in debris disk of young nearby A6V star Pictoris. We observed system with first light Magellan Adaptive Optics (MagAO) system. In Paper I we presented CCD detection this MagAO+VisAO. Here present four MagAO+Clio images b at 3.1 $μ$m, 3.3 $L^\prime$, $M^\prime$, including observation fundamental CH$_4$...
We present the first ground-based CCD ($\lambda < 1\mu$m) image of an extrasolar planet. Using MagAO's VisAO camera we detected giant planet (EGP) $\beta$ Pictoris b in $Y$-short ($Y_S$, 0.985 $\mu$m), at a separation $0.470 \pm 0.010''$ and contrast $(1.63 0.49) \times 10^{-5}$. This detection has signal-to-noise ratio 4.1, with empirically estimated upper-limit on false alarm probability 1.0%. also new photometry from NICI instrument Gemini-South telescope, $CH_{4S,1\%}$ ($1.58$ $\mu m$),...
We utilized the new high-order (250-378 mode) Magellan Adaptive Optics system (MagAO) to obtain very high spatial resolution observations in "visible light" with MagAO's VisAO CCD camera. In good-median seeing conditions of (0.5-0.7") we find MagAO delivers individual short exposure images as good 19 mas optical resolution. Due telescope vibrations, long (60s) r' (0.63 micron) are slightly coarser at FWHM=23-29 (Strehl ~28%) bright (R<9 mag) guide stars. These highest filled-aperture...
We are developing a stable and precise spectrograph for the Large Binocular Telescope (LBT) named "iLocater." The instrument comprises three principal components: cross-dispersed echelle that operates in YJ-bands (0.97-1.30 microns), fiber-injection acquisition camera system, wavelength calibration unit. iLocater will deliver high spectral resolution (R~150,000-240,000) measurements permit novel studies of stellar substellar objects solar neighborhood including extrasolar planets. Unlike...
The heart of the 6.5 Magellan AO system (MagAO) is a 585 actuator adaptive secondary mirror (ASM) with <1 msec response times (0.7 ms typically). This will allow low emissivity and high-contrast science. We fabricated high order (561 mode) pyramid wavefront sensor (similar to that now successfully used at Large Binocular Telescope). relatively count (and small projected ~23 cm pitch) allows moderate Strehls be obtained by MagAO in "visible" (0.63-1.05 μm). To take advantage this we have an...
MagAO is the new adaptive optics system with visible-light and infrared science cameras, located on 6.5-m Magellan "Clay" telescope at Las Campanas Observatory, Chile. The instrument locks natural guide stars (NGS) from 0th to 16th R-band magnitude, measures turbulence a modulating pyramid wavefront sensor binnable 28×28 7×7 subapertures, uses 585-actuator secondary mirror (ASM) provide wavefronts two cameras. mutated clone of similar AO systems Large Binocular Telescope (LBT) Mt. Graham,...
One of the primary goals exoplanet science is to find and characterize habitable planets, direct imaging will play a key role in this effort. Though true Earth analog likely out reach from ground, coming generation giant telescopes many planets near zones (HZs) nearby stars. Radial velocity transit searches indicate that such are common, but them require achieving extreme contrasts at very small angular separations, posing challenges for adaptive optics (AO) system design. Giant HZ may even...
The Magellan Clay telescope is a 6.5m Gregorian located in Chile at Las Campanas Observatory. design allows for an adaptive secondary mirror that can be tested off-sky straightforward manner. We have fabricated 85 cm diameter aspheric with our subcontractors and partners, the ASM passed acceptance tests July 2010. This has 585 actuators <1 msec response times (0.7 ms typically). will allow low emissivity AO science. achieve very high Strehls (~98%) Mid-IR (3-26 microns) BLINC/MIRAC4 science...
We review astronomical results in the visible (λ<1μm) with adaptive optics. Other than a brief period early 1990s, there has been little science done AO until recently. The most productive system to date is our 6.5m Magellan telescope (MagAO). MagAO an advanced Adaptive Secondary at Chile. This secondary 585 actuators < 1 msec response times (0.7 ms typically). use pyramid wavefront sensor. relatively small actuator pitch (~23 cm/subap) allows moderate Strehls be obtained (0.63-1.05...
We present the novel design, laboratory verification, and on-sky performance of our advanced triplet atmospheric dispersion corrector (ADC), an important component Magellan Adaptive Optics system (MagAO), which recently achieved first light in December 2012. High-precision broadband (0.5-1.0 microns) correction at visible wavelengths is essential both for wavefront sensing (WFS) on fainter guide stars, performing AO science using VisAO camera. At 2 airmasses (60 degrees from zenith) over...
WISE J085510.83-071442.5 (hereafter, 0855-07) is the coolest Y dwarf known to date and located at a distance of 2.31 ± 0.08 pc, giving it fourth largest parallax any star or brown system. We report deep z-band observations 0855-07 using FORS2 on UT1/Very Large Telescope. do not detect counterpart in our images estimate brightness upper limit AB mag > 24.8 (Fν < 0.45 μJy) 910 65 nm with 3σ confidence. combine previous near- mid-infrared photometry place constraints atmospheric properties via...
Enabling efficient injection of light into single-mode fibers (SMFs) is a key requirement in realizing diffraction-limited astronomical spectroscopy on ground-based telescopes. SMF-fed spectrographs, facilitated by the use adaptive optics (AO), offer distinct advantages over comparable seeing-limited designs, including higher spectral resolution within compact and stable instrument volume, telescope independent spectrograph design. iLocater an extremely precise radial velocity (EPRV) being...
We utilize the new Magellan adaptive optics system (MagAO) to image binary proplyd LV 1 in Orion Trapezium at Hα. This is among first AO results visible wavelengths. The Hα clearly shows ionization fronts, interproplyd shell, and cometary tails. Our astrometric measurements find no significant relative motion between components over ∼18 yr, implying that a low-mass system. also analyze Large Binocular Telescope observations, point source which may be embedded protostar's photosphere...
We present high resolution adaptive optics (AO) corrected images of the silhouette disk Orion 218-354 taken with Magellan AO (MagAO) and its visible light camera, VisAO, in simultaneous differential imaging (SDI) mode at H-alpha. This is first image a circumstellar seen among results literature. derive extent, geometry, intensity extinction profiles find, contrast previous work, that likely optically-thin Our data provide an estimate column density primitive, ISM-like grains as function...
The LINC-NIRVANA Pathfinder experiment is a test-bed to verify very complex sub-system: the Ground-layer Wavefront Sensor, or GWS. will test GWS in its final working environment and demonstrate on-sky performance achievable with multiple natural guide star, ground-layer adaptive optics system wide FoV. uses up 12 stars within 2.8'-6' annular field of view drives LBT secondary mirror correct lower layers atmospheric turbulence. This paper trace path instrument on way First Light November...
Abstract Precision radial velocity spectrographs that use adaptive optics (AO) show promise to advance telescope observing capabilities beyond those of seeing-limited designs. We are building a spectrograph for the Large Binocular Telescope (LBT) named iLocater uses AO inject starlight directly into single mode fibers. iLocater's first acquisition camera system (the SX camera), which receives light from one 8.4 m diameter primary mirrors LBT, was initially installed in summer 2019 and has...
ABSTRACT Diffraction-limited radial-velocity instruments offer a pathway towards improved precision and stability, the exploration of new parameter spaces at high spatial spectral resolution. However, achieving necessary performance requires careful instrument design considerable on-sky testing. We describe construction ‘Little iLocater’ (Lili), compact spectrograph that has been used to validate front-end fibre-injection system iLocater spectrograph. present design, assembly, using data...
The Magellan Adaptive Secondary AO system, scheduled for first light in the fall of 2011, will be able to simultaneously perform diffraction limited science both mid-IR, using BLINC/MIRAC4 10μm camera, and visible our novel VisAO camera. camera operate as either an imager, a CCD47 with 8.5 mas pixels, or IFS, custom fiber array at focal plane 20 elements its highest resolution mode. In imaging mode, have full suite filters, coronagraphic occulting spots, SDI prism/filters. mode should...
The Acquisition Guiding and Wavefront Sensing System (AGWS) is responsible for making the measurements required to keep optics of seven-segment GMT coaligned, phased, pointing in correct direction, conforming mirror shape. AGWS consists four identical probes that patrol outer parts field view. Each probe comprised two channels. visible channel contains can provide high-speed full aperture guiding, segment or Shack-Hartmann wavefront sensing feeding an EMCCD camera. In natural seeing...
We present descriptions of the alignment and calibration tests Pathfinder, which achieved first light during our 2013 commissioning campaign at LBT. The full LINC-NIRVANA instrument is a Fizeau interferometric imager with fringe tracking 2-layer natural guide star multi-conjugate adaptive optics (MCAO) systems on each eye MCAO correction for side using ground layer wavefront sensor that drives LBT secondary mirror mid-high Xinetics 349 actuator DM conjugated to an altitude 7.1 km. When...
The GMT is an aplanatic Gregorian telescope consisting of 7 primary and secondary mirror segments that must be phased to within a fraction imaging wavelength allow the 25.4 meter reach its diffraction limit. When operating in Laser Tomographic Adaptive Optics (LTAO) mode, on-axis guide stars will not available for segment phasing. In this GMT's Acquisition, Guiding, Wavefront Sensing system (AGWS) deploy four pickoff probes acquire natural 6-10 arcmin annular FOV guiding, active optics,...
The positions of the IRAS counterparts to 420 OH/IR stars in Arecibo sky (0° < δ +38°) are usually accurate better than 10''. But every star has recently been observed by Two Micron All Sky Survey (2MASS), which provides ∼02 quality positions, while those with |b| ≤ 45 have also Midcourse Space Experiment (MSX), ∼2'' positions. We use MSX and/or coordinates guide us 2MASS for 134 images second release Point Source Catalog. An unexpected by-product having J-H versus H-Ks plot generated from...
The Magellan Clay telescope is a 6.5m Gregorian located in southern Chile at Las Campanas Observatory. design allows for an adaptive secondary mirror that can be tested off-sky straight-forward manner. We have fabricated 85 cm diameter aspheric with our subcontractors and partners. This has 585 actuators <1 msec response times. chopping will allow low emissivity AO science. achieve very high Strehls (~98%) the Mid-IR (8-26 microns) BLINC/MIRAC4 science camera. first "super-resolution"...
The Magellan AO system combines a pyramid wavefront sensor and high-order adaptive secondary mirror, will see first light on the Clay telescope in November 2012. With 24 cm projected actuator pitch, this powerful enable good correction optical (0.5 to 1 μm). Realistic laboratory testing has produced Strehl ratios greater than 40% i' (0.765 μm) bright simulated stars. On fainter stars our visible camera, VisAO, work partially corrected regime with only short moments of correction. We have...