OPTIMIZED PRINCIPAL COMPONENT ANALYSIS ON CORONAGRAPHIC IMAGES OF THE FOMALHAUT SYSTEM

We present the results of a study to optimize the principal component analysis (PCA) algorithm for planet detection, a new algorithm complementing angular differential imaging and locally optimized combination of images (LOCI) for increasing the contrast achievable next to a bright star. The stellar point spread function (PSF) is constructed by removing linear combinations of principal components, allowing the flux from an extrasolar planet to shine through. The number of principal components used determines how well the stellar PSF is globally modeled. Using more principal components may decrease the number of speckles in the final image, but also increases the background noise. We apply PCA to Fomalhaut Very Large Telescope NaCo images acquired at 4.05 μm with an apodized phase plate. We do not detect any companions, with a model dependent upper mass limit of 13-18 M Jup from 4-10 AU. PCA achieves greater sensitivity than the LOCI algorithm for the Fomalhaut coronagraphic data by up to 1 mag. We make several adaptations to the PCA code and determine which of these prove the most effective at maximizing the signal-to-noise from a planet very close to its parent star. We demonstrate that optimizing the number of principal components used in PCA proves most effective for pulling out a planet signal.

[1]  B. Macintosh,et al.  Angular Differential Imaging: A Powerful High-Contrast Imaging Technique , 2005, astro-ph/0512335.

[2]  S. Ridgway,et al.  Exoplanet Imaging with a Phase-induced Amplitude Apodization Coronagraph. I. Principle , 2004, astro-ph/0412179.

[3]  Julien H. Girard,et al.  An apodizing phase plate coronagraph for VLT/NACO , 2010, Astronomical Telescopes + Instrumentation.

[4]  D. Mouillet,et al.  A giant planet candidate near a young brown dwarf - Direct VLT/NACO observations using IR wavefront sensing , 2004 .

[5]  David Mouillet,et al.  NAOS, the first AO system of the VLT: on-sky performance , 2003, SPIE Astronomical Telescopes + Instrumentation.

[6]  Adam Burrows,et al.  SPECTRAL AND PHOTOMETRIC DIAGNOSTICS OF GIANT PLANET FORMATION SCENARIOS , 2011, 1108.5172.

[7]  A. Vigan,et al.  The International Deep Planet Survey - I. The frequency of wide-orbit massive planets around A-stars , 2012, 1206.4048.

[8]  R. Soummer,et al.  DETECTION AND CHARACTERIZATION OF EXOPLANETS AND DISKS USING PROJECTIONS ON KARHUNEN–LOÈVE EIGENIMAGES , 2012, 1207.4197.

[9]  M. Kenworthy,et al.  PLANETARY CONSTRUCTION ZONES IN OCCULTATION: DISCOVERY OF AN EXTRASOLAR RING SYSTEM TRANSITING A YOUNG SUN-LIKE STAR AND FUTURE PROSPECTS FOR DETECTING ECLIPSES BY CIRCUMSECONDARY AND CIRCUMPLANETARY DISKS , 2011, 1108.4070.

[10]  C. A. Grady,et al.  NEW TECHNIQUES FOR HIGH-CONTRAST IMAGING WITH ADI: THE ACORNS-ADI SEEDS DATA REDUCTION PIPELINE , 2012, 1209.3014.

[11]  B. Macintosh,et al.  Direct Imaging of Multiple Planets Orbiting the Star HR 8799 , 2008, Science.

[12]  Laird M. Close,et al.  An Imaging Survey for Extrasolar Planets around 45 Close, Young Stars with the Simultaneous Differential Imager at the Very Large Telescope and MMT , 2007 .

[13]  B. Oppenheimer,et al.  The Gemini Deep Planet Survey , 2007, 0705.4290.

[14]  Julien H. Girard,et al.  CORONAGRAPHIC OBSERVATIONS OF FOMALHAUT AT SOLAR SYSTEM SCALES , 2012, 1212.1459.

[15]  J. Angel,et al.  First On-Sky High-Contrast Imaging with an Apodizing Phase Plate* , 2007, astro-ph/0702324.

[16]  Anne-Marie Lagrange,et al.  NAOS-CONICA first on sky results in a variety of observing modes , 2003, SPIE Astronomical Telescopes + Instrumentation.

[17]  David Lafreniere,et al.  Direct Imaging and Spectroscopy of a Planetary-Mass Candidate Companion to a Young Solar Analog , 2008, 0809.1424.

[18]  Julien H. Girard,et al.  A survey of young, nearby, and dusty stars conducted to understand the formation of wide-orbit giant planets - VLT/NaCo adaptive optics thermal and angular differential imaging , 2013 .

[19]  Paul S. Smith,et al.  SEARCHING FOR PLANETS IN HOLEY DEBRIS DISKS WITH THE APODIZING PHASE PLATE , 2014, 1412.5179.

[20]  D. Frail,et al.  A planetary system around the millisecond pulsar PSR1257 + 12 , 1992, Nature.

[21]  Suresh Sivanandam,et al.  Deep L'- and M-band Imaging for Planets around Vega and Eridani , 2008 .

[22]  Adam Amara,et al.  PYNPOINT: An image processing package for finding exoplanets , 2012, 1207.6637.

[23]  P. H. Hauschildt,et al.  Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458 , 2003 .

[24]  M. Ireland,et al.  LkCa 15: A YOUNG EXOPLANET CAUGHT AT FORMATION? , 2011, 1110.3808.

[25]  Mark Clampin,et al.  Optical Images of an Exosolar Planet 25 Light-Years from Earth , 2008, Science.

[26]  Julien H. Girard,et al.  DISCOVERY OF A PROBABLE 4–5 JUPITER-MASS EXOPLANET TO HD 95086 BY DIRECT IMAGING , 2013, 1305.7428.

[27]  CfAO,et al.  SPECKLE SUPPRESSION THROUGH DUAL IMAGING POLARIMETRY, AND A GROUND-BASED IMAGE OF THE HR 4796A CIRCUMSTELLAR DISK , 2009, 0906.3010.

[28]  Jean-Pierre Véran,et al.  Exoplanet imaging with LOCI processing: photometry and astrometry with the new SOSIE pipeline , 2010, Astronomical Telescopes + Instrumentation.