Institution(s): 1. European Southern Observatory
Time-series photometry and spectroscopy of transiting exoplanets allow us to study their atmospheres. Unfortunately, the required precision to extract atmospheric information surpasses the design specifications of most general purpose instrumentation. This results in instrumental systematics in the light curves that are typically larger than the target precision. Systematics must therefore be modelled, leaving the inference of light-curve parameters conditioned on the subjective choice of systematics models and model-selection criteria. These choices are significant contributors to the error budget, yet are often neglected when extracting exoplanet spectra. I will review the use of deterministic and stochastic systematics models commonly used for transmission and emission spectroscopy. This will cover model selection, marginalisation over families of systematic models, and Gaussian processes. I will focus on how these techniques may be used to objectively extract spectra of exoplanets in the presence of complex noise sources, therefore reliably inferring the composition and structure of their atmospheres.