Joint Astrophysical Colloquium
GalaPy: the highly optimized C++/Python spectral modelling tool for galaxies
Andrea Lapi (SISSA)
Thursday 02/05/2024 @ 11:30, Sala Antonio Sollima (IV piano Battiferro)
In this talk I will present GalaPy, a new library for modelling and fitting the spectral energy distributions of galaxies from the X-ray to the radio band, as well as the evolution of their components and dust attenuation/reradiation. On the physical side, GalaPy incorporates both empirical and physically-motivated star formation histories, state-of-the-art single stellar population synthesis libraries, a two component dust model for attenuation, an age-dependent energy conservation algorithm to compute dust reradiation, and additional sources of stellar continuum such as synchrotron, nebular/free-free emission and X-ray radiation from low and high mass binary stars. On the computational side, GalaPy implements a hybrid approach that combines the high performance of compiled C++ with the user-friendly flexibility of Python, and exploits an object-oriented design via advanced programming techniques. GalaPy is the fastest SED generation tool of its kind, with a peak performance of almost 1000 SEDs per second. The models are generated on the fly without relying on templates, thus minimizing memory consumption. It exploits fully Bayesian parameter space sampling, which allows for the inference of parameter posteriors and thus facilitates the study of the correlations between the free parameters and the other physical quantities that can be derived from modelling. The API and functions of GalaPy are under continuous development, with planned extensions in the near future (e.g., joint fitting of AGN and host galaxy, Bayesian samplers, parallelization), that I will briefly discuss toward the end of the talk.