Speaker
Description
We present ExoSim 2, a next-generation, fully modular simulator for astronomical observations, initially developed to support the study of transiting exoplanets in the context of the Ariel space mission. Implemented in Python 3 and built on an object-oriented design, ExoSim 2 is publicly available and offers a flexible, open framework for simulating time-resolved spectro-photometric data from space-based, sub-orbital, and ground-based observatories.
Its architecture is based on user-definable Task classes, allowing researchers to customise every stage of the simulation pipeline: from optical and detector models to astrophysical signals and observing strategies. ExoSim 2 also supports temporal effects across multiple timescales, enabling the simulation of a wide range of time-domain phenomena beyond planetary transits, such as stellar activity and instrumental systematics.
ExoSim 2 has been extensively validated against ArielRad and benchmarked across multiple platforms, achieving over 90% test coverage and demonstrating efficient scaling with CPU threads. The simulator is already being applied to other missions, including EXCITE, confirming its versatility and mission-agnostic design.
More than a simulator, ExoSim 2 is a framework for building simulators: a tool that enables researchers to model the physical and observational properties of complex systems. As such, it plays a key role in developing data reduction pipelines, systematics mitigation techniques, and mission planning strategies for the next generation of astronomical instruments.
