The 1D radiative-equilibrium model Exo-REM simulates young gas giants far from their star and brown dwarfs. Fluxes are calculated using the two-stream approximation assuming hemispheric closure. The radiative-convective equilibrium is solved assuming that the net flux (radiative + convective) is conservative. The conservation of flux over the pressure grid is solved iteratively using a constrained linear inversion method. Rayleigh scattering from H2, He, and H2O, as well as absorption and scattering by clouds (calculated from extinction coefficient, single scattering albedo, and asymmetry factor interpolated from precomputed tables for a set of wavelengths and particle radii), are also taken into account.

ATMOSPHERIX reads t.fits files from the Canada-France-Hawaii Telescope's near-infrared spectropolarimeter SPIRou, processes the data to remove telluric/stella contributions, and performs the correlation analysis for a given planet atmosphere template. The correlation function computes the correlation between the data and model for a grid of planet velocimetric semi-amplitude and systemic velocity. ATMOSPHERIX takes transmission spectroscopy into account and allows the user to inject a synthetic planet if desired.