Article: Ruffio, JB; Macintosh, B; Wang, JJ; Pueyo, L; Nielsen, EL; De Rosa, RJ; Czekala, I; Marley, MS; Arriaga, P; Bailey, VP; Barman, T; Bulger, J; Chilcote, J; Cotten, T; Doyon, R; Duchene, G; Fitzgerald, MP; Follette, KB; Gerard, BL; Goodsell, SJ; Graham, JR; Greenbaum, AZ; Hibon, P; Hung, LW; Ingraham, P; Kalas, P; Konopacky, Q; Larkin, JE; Maire, J; Marchis, F; Marois, C; Metchev, S; Millar-Blanchaer, MA; Morzinski, KM; Oppenheimer, R; Palmer, D; Patience, J; Perrin, M; Poyneer, L; Rajan, A; Rameau, J; Rantakyro, FT; Savransky, D; Schneider, AC; Sivaramakrishnan, A; Song, I; Soummer, R; Thomas, S; Wallace, JK; Ward-Duong, K; Wiktorowicz, S; Wolff, S; “Improving and Assessing Planet Sensitivity of the GPI Exoplanet Survey with a Forward Model Matched Filter”, Astrophysical Journal, 842 (1)
Abstract: 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-Love 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 signalto-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.
Funding Acknowledgement: NSF [AST-1411868, AST-1518332]; NASA [NNX14AJ80G, NNX15AD95G, NAS5-26555]; NASAs Science Mission Directorate; NASA Exoplanets Research Program (XRP) [NNX16AD44G]; NASA through Hubble Fellowship [51378.01-A]; Space Telescope Science Institute; Fonds de Recherche du Quebec
Funding Text: This work is based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy under a cooperative agreement with NSF on behalf of the Gemini partnership, whose membership includes NSF (United States); the National Research Council (Canada); the Comision Nacional de Investigacion Cientifica y Tecnologica (Chile); the Australian Research Council (Australia); the Ministerio da Ciencia, Tecnologia e Inovacao (Brazil); and Ministerio de Ciencia, Tecnologia e Innovacion Productiva (Argentina). GPI data are archived at the Gemini Observatory Archive33:https://archive.geminiedu/searchform. The research was supported by grants from NSF, including AST-1411868 (J.-B.R. B.M., K.F., A.R., J.L.P.) and AST-1518332 (J.J.W., R.J.D., J.R.G., and P.K.). Support was provided by grants from NASA, including NNX14AJ80G (B.M., E.N., and V.P.B.), NNX15AD95G (J.J.W., R.J.D., J.R.G., and P.K.). This work benefited from NASAs Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASAs Science Mission Directorate. K.M.M.’s and T.B.’s work is supported by the NASA Exoplanets Research Program (XRP) by cooperative agreement NNX16AD44G. M.A.M.B. was supported for this work by NASA through Hubble Fellowship grant #51378.01-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. J.R. and R.D. acknowledge support from the Fonds de Recherche du Quebec.