Extrasolar Planets via Bayesian Model Fitting

Phil Gregory

September 02, 2010

–

Abstract: I will describe a Bayesian nonlinear model fitting program based on a new hybrid Markov chain Monte Carlo (HMCMC) algorithm which incorporates parallel tempering, simulated annealing and genetic crossover operations. Each of these features facilitate the detection of a global minimum in chi-squared. By combining all three, the HMCMC greatly increases the probability of realizing this goal. The algorithm also incorporates a new form of differential evolution to handle highly correlated parameters. When applied to the Kepler problem it acts as a powerful multi-planet Kepler periodogram. Recently, the algorithm has been used to resolve the issue of a disputed second planet in 47 Ursae Majoris and provide evidence of a new third planet. The talk will commence with an introduction to Bayesian analysis and MCMC.