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Transit Analysis Package Zach Gazak John Tonry John Johnson
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Extrasolar Planets 1992: First discovered (pulsar timing variations) 1995: First orbiting Main Sequence star (radial velocity) 1999: First photometric transit light curve: (Charbonneau et al. 2000)
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Transiting Extrasolar Planets ~80 transiting exoplanets Transits give us access to the geometry of the system (Charbonneau et al. 2000) NASA
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Modeling Transit Photometry Analytic light curve of (Mandel & Agol 2002) Period, Inclination, Rp, a, Rs, e, ω, T mid, limb darkening Inclination, Rp/Rs, a/Rs:
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Parameter Statistics: MCMC Markov Chain Monte Carlo Gives access to Bayesian probability distribution model x 0 trial state x ’ Likelihood: –– ‾ 2 ~exp [ ] ℒ’ℒ’ If z ≤ then x 1 = x ’ ℒ’ℒ’ ℒ0ℒ0 0≤z≤1 (random uniform) otherwise, x 1 = x 0 More likely states always selected, but MCMC can explore.
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Parameter Statistics: MCMC Markov Chain Monte Carlo Gives access to Bayesian probability distribution model x 0 trial state x ’ Likelihood: –– ‾ 2 ~exp [ ] ℒ’ℒ’ ℒ’ℒ’ ℒ0ℒ0 meets Jump probability?
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Parameter Statistics: MCMC Markov Chain Monte Carlo Gives access to Bayesian probability distribution model x 0 trial state x ’ More likely states always selected, but MCMC can explore.... xNxN
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MCMC Bayesian Distributions 15.1%
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MCMC Bayesian Distributions
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Testing the MCMC Algorithm Generate and Analyze Synthetic Transits WASP 10bHAT 12b
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Testing the MCMC Algorithm Transits of varying precision must agree:
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Where is Transit Science Going?
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Is the “Classic” MCMC Enough? Most light curves show correlated “red” noise: But “classic” MCMC is not able to compensate.
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Wavelet Processing “Fourier Like” but sensitive to frequency and scale. Daubechies 4th order
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Wavelet Processing “Fourier Like” but sensitive to frequency and scale. Daubechies 4th order
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Red Noise Filtering How “Likely” is the noise described by a (σ white, σ red ) pair? (Carter & Winn 2009) Maximize that “Wavelet Likelihood”:
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Wavelet Basis MCMC Wavelet decompose residuals (data - model fit) Use wavelet likelihood instead of “Classic”
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Wavelet Basis MCMC For contaminated data, “Classic” MCMC is insufficient! Severely underestimates probability distributions. “True” value Classic Wavelet
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TrES-3b
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TAP in Action
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Transit Analysis Package Zach Gazak John Tonry John Johnson
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