Angular Differential Imaging: A Powerful High-Contrast Imaging Technique

By C. Marois, D. Lafrèniere, R. Doyon, B. Macintosh, D. Nadeau. 2005

961 citations recorded by the source corpus.

Angular differential imaging is a high-contrast imaging technique that reduces quasistatic speckle noise and facilitates the detection of nearby companions. A sequence of images is acquired with an altitude/azimuth telescope while the instrument field derotator is switched off. This keeps the instrument and telescope optics aligned and allows the field of view to rotate with respect to the instrument. For each image, a reference point-spread function (PSF) is constructed from other appropriately selected images of the same sequence and subtracted to remove quasistatic PSF structure. All residual images are then rotated to align the field and are combined. Observed performances are reported for Gemini North data. It is shown that quasistatic PSF noise can be reduced by a factor ~5 for each image subtraction. The combination of all residuals then provides an additional gain of the order of the square root of the total number of acquired images. A total speckle noise attenuation of 20-50 is obtained for a 1 hr long observing sequence compared to a single 30 s exposure. A PSF noise attenuation of 100 was achieved for a 2 hr long sequence of images of Vega, reaching a 5 σ contrast of 20 mag for separations greater than 8''. For a 30 minute long sequence, ADI achieves signal-to-noise ratios 30 times better than a classical observation technique. The ADI technique can be used with currently available instruments to search for ~1MJup exoplanets with orbits of radii between 50 and 300 AU around nearby young stars. The possibility of combining the technique with other high-contrast imaging methods is briefly discussed.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d6aefa76cc9053beb85c3d3871a18826059aadf0

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In Astronomy and Astrophysics

1. B. Bowler
2. Michael C. Liu
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4. Jon Fortney
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Citations in the corpus

• A COMBINED SUBARU/VLT/MMT 1–5 μm STUDY OF PLANETS ORBITING HR 8799: IMPLICATIONS FOR ATMOSPHERIC PROPERTIES, MASSES, AND FORMATION (2011, methodology): “All of our data were taken in angular differential imaging mode (Marois et al. 2006), where the instrument rotator is adjusted to stay at a fixed angle with respect to the (changing) parallactic angle, resulting in the field of view rotating with time.”
• DISCOVERY OF A PROBABLE 4–5 JUPITER-MASS EXOPLANET TO HD 95086 BY DIRECT IMAGING (2013, methodology): “Stellarhalo subtraction was also done using all the ADI algorithms implemented in the pipeline: cADI, sADI (Marois et al. 2006), and LOCI (Lafrenière et al. 2007).”
• ORBITAL MOTION OF HR 8799 b, c, d USING HUBBLE SPACE TELESCOPE DATA FROM 1998: CONSTRAINTS ON INCLINATION, ECCENTRICITY, AND STABILITY (2011, methodology): “Advanced point spread function (PSF) subtractions based on rolldeconvolution or angular differential imaging (Schneider & Silverstone 2003; Marois et al. 2006a; Lafrenière et al. 2007b) are required because the coronagraph alone is not sufficient to provide sufficient dynamic range, and the images…”
• PLANETS AROUND LOW-MASS STARS (PALMS). IV. THE OUTER ARCHITECTURE OF M DWARF PLANETARY SYSTEMS (2014, methodology): “Observing strategies based on field of view (FOV) rotation (Liu 2004; Marois et al. 2006) and/or chromatic dependencies of the PSF pattern (e.g., Sparks & Ford 2002; Marois et al. 2005; Thatte et al. 2007; Biller et al. 2008; Crepp et al. 2011) together with more sophisticated processing techniques…”
• Photometric characterization of exoplanets using angular and spectral differential imaging (2010, methodology): “…allow to use different observing strategies such as Spectral Differential Imaging (SDI, Racine et al. 1999) or Angular Differential Imaging (ADI, Marois et al. 2006) to obtain data which will be analyzed using advanced methods such as Spectral Deconvolution (Sparks & Ford 2002) or Localy…”
• Imaging Extrasolar Giant Planets (2016, methodology): “Different methods of PSF subtraction can bias photometry if planet self-subtraction or speckle over-subtraction is not properly corrected (e.g., Marois et al. 2006; Lafrenière et al. 2007a; Soummer et al. 2012).”
• Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager (2015, neutral): “We made use of the basic ADI or classic ADI ( 65 ), LOCI ( 73 ) with the typical parameters dr=5, Na=200, g=2, and N_delta=0.75 FWHM, and PCA keeping 10% of the modes.”
• CLOUDS AND CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HR8799b (2011, methodology): “Photometry On August 7 2009 (UT), when OSIRIS was too warm to operate, an angular differential imaging (ADI, Marois et al. 2006) sequence was taken with NIRC2 using four narrow-band filters in the K-band window (see Table ??).”
• A New Algorithm for Point-Spread Function Subtraction in High-Contrast Imaging: A Demonstration with Angular Differential Imaging (2007, methodology): “At all separations, the LOCI algorithm yields a S/N that is better than or equal to that obtained with the algorithm of Marois et al. (2006).”
• EXOPLANET ALBEDO SPECTRA AND COLORS AS A FUNCTION OF PLANET PHASE, SEPARATION, AND METALLICITY (2010, methodology): “…2002; Kasdin et al. 2003; Guyon et al. 2005; Trauger & Traub 2007; Mawet et al. 2009), external occulters (Cash 2006), and optical nullers (Wallace et al. 2000; Martin Levine et al. 2006), as well as post-processing algorithms such as those used by Marois et al. (2006) and Lafreniere et al. (2007).”
• FUNDAMENTAL LIMITATIONS OF HIGH CONTRAST IMAGING SET BY SMALL SAMPLE STATISTICS (2014, methodology): “Fortunately, observing strategies such as angular differential imaging (ADI, Marois et al. 2006), and data reduction techniques such as the locally optimized combination of images (LOCI, Lafrenière et al. 2007; Marois et al. 2008) or principal component analysis (PCA, Soummer et al. 2012; Meshkat…”
• THE GEMINI/NICI PLANET-FINDING CAMPAIGN: THE FREQUENCY OF PLANETS AROUND YOUNG MOVING GROUP STARS (2013, background): “…(2) dual-channel imaging for spectral differential imaging (SDI; Racine et al. 1999; Marois et al. 2005; Biller et al. 2007), and (3) operation in a fixed Cassegrain rotator mode for angular differential imaging (ADI; Liu 2004; Marois et al. 2006; Lafrenière et al. 2007b; Biller et al. 2008).”
• Adaptive Optics for Astronomy (2012, background): “It was first demonstrated by Marois et al. (2006) and is now widely used for high-contrast imaging.”
• DETECTION AND CHARACTERIZATION OF EXOPLANETS AND DISKS USING PROJECTIONS ON KARHUNEN–LOÈVE EIGENIMAGES (2012, background): “Indeed, most recent direct imaging results were enabled by key advances in observational procedures, e.g. Angular Differential Imaging (ADI) (Marois et al. 2006), simultaneous imaging of contiguous wavelengths (Marois et al. 2000; Sparks & Ford 2002; Pueyo et al. 2012), in conjunction with…”
• Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk (2018, methodology): “For this image the data were processed with a classical ADI reduction technique (Marois et al. 2006) to minimize self-subtraction of the disk.”
• Combining high-dispersion spectroscopy with high contrast imaging : Probing rocky planets around our nearest neighbors (2015, background): “These include Angular Differential Imaging (ADI; Marois et al. 2006), Spectral Differential Imaging (SDI; Racine et al. 1999), Locally Optimized Combinations of Images (LOCI; Lafrenière et al. 2007), and Principal Component Analysis (PCA; Amara & Quanz 2012, Soummer et al. 2012, Meshkat et al.…”
• SPHERE: the exoplanet imager for the Very Large Telescope (2019, background): “…timescales the alignment needed for coronagraphic extinction at any given time, it is also needed with an even finer accuracy within a typically 1-hour long observation sequence to guarantee the performance of speckle subtraction thanks to an- gular differential imaging (ADI; Marois et al. 2006).”
• A YOUNG PROTOPLANET CANDIDATE EMBEDDED IN THE CIRCUMSTELLAR DISK OF HD 100546 (2013, neutral): “We used the L27 camera (∼ 27 mas pixel−1) with the L′ filter (λc = 3.8µm, ∆λ = 0.62µm) in angular differential imaging mode (ADI; Marois et al. 2006).”