Improving and Assessing Planet Sensitivity of the GPI Exoplanet Survey with a Forward Model Matched Filter
Improving and Assessing Planet Sensitivity of the GPI Exoplanet Survey with a Forward Model Matched Filter
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使用正向模型匹配滤波器改进和评估 GPI 系外行星巡天的行星灵敏度
DOI：
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发表时间：
2017
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通讯作者：
S. Wolff
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作者：
J. Ruffio;B. Macintosh;Jason J. Wang;L. Pueyo;E. Nielsen;E. Nielsen;R. J. Rosa;I. Czekala;M. Marley;P. Arriaga;V. Bailey;T. Barman;J. Bulger;J. Chilcote;T. Cotten;R. Doyon;G. Duchêne;M. Fitzgerald;K. Follette;B. Gerard;B. Gerard;S. Goodsell;J. Graham;A. Greenbaum;P. Hibon;L. Hung;P. Ingraham;P. Kalas;P. Kalas;Q. Konopacky;J. Larkin;J. Maire;F. Marchis;C. Marois;C. Marois;S. Metchev;S. Metchev;M. Millar;K. Morzinski;R. Oppenheimer;D. Palmer;J. Patience;M. Perrin;L. Poyneer;A. Rajan;J. Rameau;F. Rantakyrö;D. Savransky;A. Schneider;A. Sivaramakrishnan;I. Song;R. Soummer;Sandrine Thomas;J. Wallace;K. Ward;S. Wiktorowicz;S. Wolff
我们提出了一种新的匹配滤波器算法直接检测点源在明亮的恒星附近。首先使用Karhunen-Loéve图像处理（KLIP）算法减去恒星点扩散函数（PSF），并使用角度和光谱差分成像（ADI和SDI）。通过计算图像中每个位置处的PSF的前向模型，将KLIP引起的天体物理信号失真包括在匹配滤波器模板中。为了优化算法的性能，我们进行了广泛的行星注入和恢复测试，并调整系外行星光谱模板和KLIP减少积极性，以最大限度地提高恢复行星的信噪比（S/N）。我们表明，只有两个光谱模板是必要的，以最小的S/N损失恢复任何年轻的木星系外行星。我们还开发了一个完整的管道，用于点源候选者的自动检测，受试者工作特征（ROC）的计算，基于假阳性的对比度曲线和完整性轮廓。我们以统一的方式处理来自双子座行星成像仪系外行星调查的330多个数据集，并评估GPI典型的灵敏度作为星星和假设的伴星光谱类型的函数。这项工作允许第一次比较不同的检测算法在调查规模占行星的完整性和假阳性率。我们表明，新的前向模型匹配滤波器允许检测比传统的互相关技术与高斯PSF模板相同的假阳性率的50%微弱的对象。
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.