Near-instantaneous Atmospheric Retrievals and Model Comparison with FASTER

Fuente: arXiv
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Auteurs principaux: Lueber, Anna, Karchev, Konstantin, Fisher, Chloe, Heim, Matthias, Trotta, Roberto, Heng, Kevin
Format: Preprint
Publié: 2025
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author Lueber, Anna
Karchev, Konstantin
Fisher, Chloe
Heim, Matthias
Trotta, Roberto
Heng, Kevin
author_facet Lueber, Anna
Karchev, Konstantin
Fisher, Chloe
Heim, Matthias
Trotta, Roberto
Heng, Kevin
contents In the era of the James Webb Space Telescope (JWST), the dramatic improvement in the spectra of exoplanetary atmospheres demands a corresponding leap forward in our ability to analyze them: atmospheric retrievals need to be performed on thousands of spectra, applying to each large ensembles of models (that explore atmospheric chemistry, thermal profiles and cloud models) to identify the best one(s). In this limit, traditional Bayesian inference methods such as nested sampling become prohibitively expensive. We introduce FASTER (Fast Amortized Simulation-based Transiting Exoplanet Retrieval), a neural-network based method for performing atmospheric retrieval and Bayesian model comparison at a fraction of the computational cost of classical techniques. We demonstrate that the marginal posterior distributions of all parameters within a model as well as the posterior probabilities of the models we consider match those computed using nested sampling both on mock spectra, and for the real NIRSpec PRISM spectrum of WASP-39b. The true power of the FASTER framework comes from its amortized nature, which allows the trained networks to perform practically instantaneous Bayesian inference and model comparison over ensembles of spectra -- real or simulated -- at minimal additional computational cost. This offers valuable insight into the expected results of model comparison (e.g., distinguishing cloudy from cloud-free and isothermal from non-isothermal models), as well as their dependence on the underlying parameters, which is computationally unfeasible with nested sampling. This approach will constitute as large a leap in spectral analysis as the original retrieval methods based on Markov Chain Monte Carlo have proven to be.
format Preprint
id arxiv_https___arxiv_org_abs_2502_18045
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Near-instantaneous Atmospheric Retrievals and Model Comparison with FASTER
Lueber, Anna
Karchev, Konstantin
Fisher, Chloe
Heim, Matthias
Trotta, Roberto
Heng, Kevin
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Data Analysis, Statistics and Probability
In the era of the James Webb Space Telescope (JWST), the dramatic improvement in the spectra of exoplanetary atmospheres demands a corresponding leap forward in our ability to analyze them: atmospheric retrievals need to be performed on thousands of spectra, applying to each large ensembles of models (that explore atmospheric chemistry, thermal profiles and cloud models) to identify the best one(s). In this limit, traditional Bayesian inference methods such as nested sampling become prohibitively expensive. We introduce FASTER (Fast Amortized Simulation-based Transiting Exoplanet Retrieval), a neural-network based method for performing atmospheric retrieval and Bayesian model comparison at a fraction of the computational cost of classical techniques. We demonstrate that the marginal posterior distributions of all parameters within a model as well as the posterior probabilities of the models we consider match those computed using nested sampling both on mock spectra, and for the real NIRSpec PRISM spectrum of WASP-39b. The true power of the FASTER framework comes from its amortized nature, which allows the trained networks to perform practically instantaneous Bayesian inference and model comparison over ensembles of spectra -- real or simulated -- at minimal additional computational cost. This offers valuable insight into the expected results of model comparison (e.g., distinguishing cloudy from cloud-free and isothermal from non-isothermal models), as well as their dependence on the underlying parameters, which is computationally unfeasible with nested sampling. This approach will constitute as large a leap in spectral analysis as the original retrieval methods based on Markov Chain Monte Carlo have proven to be.
title Near-instantaneous Atmospheric Retrievals and Model Comparison with FASTER
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
Data Analysis, Statistics and Probability
url https://arxiv.org/abs/2502.18045