ExoSim 2. The new time-domain simulator applied to the Ariel space mission

<p>ExoSim 2 is a time-domain simulator for exoplanet observations. The software can simulate exoplanetary transit, eclipse and phase curve observations from ground and space-based instruments. Such simulation can capture temporal effects, such as correlated noise and systematics on the light curve. The simulator will produce spectral images like those produced by an actual observation.</p> <p>ExoSim 2 has been developed for the Ariel Space Mission, to assess the impact of astronomical and instrumental systematic on astrophysical measurement, and to prepare the data reduction pipeline against realistic data sets. ExoSim 2 output can be utilised by different data reduction methods, not only to determine the best pipeline strategy to remove the systematics in the measurements but also to assess the confidence level of retrieved quantities.</p> <p>ExoSim 2 is a refactored version of ExoSim: an end-to-end simulator that models noise and systematics in a dynamical simulation. The first version of ExoSim (Sarkar et al. 2020) was developed for the Ariel Space Mission, then adapted to the James Webb Telescope and presented to the community as JexoSim (Sarkar et al. 2019 and Sarkar et al. 2021).</p> <p>ExoSim 2 is meant to be easier to use than its predecessor and largely customizable. It is completely written in Python, tested against Python 3.7+, and follows the object-oriented philosophy. It comes with an installer, documented examples, a comprehensive guide, and almost every part of the code can be replaced by a user-defined function, which allows the user to include new functionalities to the simulator.</p> <p>We believe that ExoSim 2 is a versatile tool, which can be used for the development of instruments other than Ariel, or to assess the impact of different astronomical or instrumental systematics.</p>