Improving and Assessing Planet Sensitivity of the GPI Exoplanet Survey with a Forward Model Matched Filter

Journal Article · Sat Jun 10 00:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA72DD· OSTI ID:22663532

Ruffio, Jean-Baptiste; Macintosh, Bruce; Nielsen, Eric L.; Czekala, Ian; Bailey, Vanessa P.; Follette, Katherine B. ^[1]; Wang, Jason J.; Rosa, Robert J. De; Duchêne, Gaspard ^[2]; Pueyo, Laurent ^[3]; Marley, Mark S. ^[4]; Arriaga, Pauline; Fitzgerald, Michael P. ^[5]; Barman, Travis ^[6]; Bulger, Joanna ^[7]; Chilcote, Jeffrey ^[8]; Cotten, Tara ^[9]; Doyon, Rene ^[10]; Gerard, Benjamin L. ^[11]; others, and

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1. Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA, 94305 (United States)
2. Astronomy Department, University of California, Berkeley CA, 94720 (United States)
3. Space Telescope Science Institute, Baltimore, MD, 21218 (United States)
4. NASA Ames Research Center, Mountain View, CA, 94035 (United States)
5. Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095 (United States)
6. Lunar and Planetary Laboratory, University of Arizona, Tucson AZ, 85721 (United States)
7. Subaru Telescope, NAOJ, 650 North A’ohoku Place, Hilo, HI 96720 (United States)
8. Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON, M5S 3H4 (Canada)
9. Department of Physics and Astronomy, University of Georgia, Athens, GA, 30602 (United States)
10. Institut de Recherche sur les Exoplanètes, Départment de Physique, Université de Montréal, Montréal QC, H3C 3J7 (Canada)
11. University of Victoria, 3800 Finnerty Road, Victoria, BC, V8P 5C2 (Canada)

We present a new matched-filter algorithm for direct detection of point sources in the immediate vicinity of bright stars. The stellar point-spread function (PSF) is first subtracted using a Karhunen-Loéve image processing (KLIP) algorithm with angular and spectral differential imaging (ADI and SDI). The KLIP-induced distortion of the astrophysical signal is included in the matched-filter template by computing a forward model of the PSF at every position in the image. To optimize the performance of the algorithm, we conduct extensive planet injection and recovery tests and tune the exoplanet spectra template and KLIP reduction aggressiveness to maximize the signal-to-noise ratio (S/N) of the recovered planets. We show that only two spectral templates are necessary to recover any young Jovian exoplanets with minimal S/N loss. We also developed a complete pipeline for the automated detection of point-source candidates, the calculation of receiver operating characteristics (ROC), contrast curves based on false positives, and completeness contours. We process in a uniform manner more than 330 data sets from the Gemini Planet Imager Exoplanet Survey and assess GPI typical sensitivity as a function of the star and the hypothetical companion spectral type. This work allows for the first time a comparison of different detection algorithms at a survey scale accounting for both planet completeness and false-positive rate. We show that the new forward model matched filter allows the detection of 50% fainter objects than a conventional cross-correlation technique with a Gaussian PSF template for the same false-positive rate.

• OSTI ID: 22663532
• Journal Information: Astrophysical Journal, Vol. 842, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ALGORITHMS
ASTROPHYSICS
COMPARATIVE EVALUATIONS
CORRELATIONS
DETECTION
FILTERS
IMAGES
INJECTION
LOSSES
NOISE
OPTICS
PERFORMANCE
PLANETS
REDUCTION
RESOLUTION
SENSITIVITY
SIGNAL-TO-NOISE RATIO
SPECTRA
STARS