Séminaire Doctorants / Seminar PhD students |
| « MCMC parameter retrieval for the ARIEL/CASE mission » |
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Lahna Admeziem |
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Transit spectroscopy is a widely spread characterization method for exoplanet atmospheres. Its content is constrained using the exoplanet transit spectrum. Forward models based on radiative transfer are used to transform atmospheric parameters into a prediction of a transit spectrum. We then constrain the model parameters by comparing models with the measurements.
These models have a highly non-linear behavior with respect to their input parameters. A key question is whether this non-linearity affects the parameter's posterior distributions obtained from retrievals using the Markov Chain Monte Carlo (MCMC) method. In this work, which takes place in the ARIEL/CASE mission context, we show that this nonlinearity does have an impact, as it introduces a bias in the retrieved values of the physical parameters. We present the method we used to identify and analyze this effect, not only in the case of simulated data for targets of the ARIEL/CASE mission, but also applying it to contemporaneous data sets, such as James Webb Space Telescope (JWST) observations. |
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vendredi 6 février 2026 - 16:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique |
| Page web du Séminaire / Seminar's webpage |