The dynamical mass of the Coma cluster from deep learning

In 1933, Fritz Zwicky's famous investigations of the mass of the Coma cluster led him to infer the existence of dark matter¹. His fundamental discoveries have proven to be foundational to modern cosmology; as we now know, such dark matter makes up 85% of the matter and 25% of the mass-energy content in the universe. Galaxy clusters like Coma are massive, complex systems of dark matter, hot ionized gas and thousands of galaxies, and serve as excellent probes of the dark matter distribution. However, empirical studies show that the total mass of such systems remains elusive and difficult to precisely constrain. Here we present new estimates for the dynamical mass of the Coma cluster based on Bayesian deep learning methodologies developed in recent years. Using our novel data-driven approach, we predict Coma's M_200c mass to be 10^15.10±0.15 h⁻¹ M_⊙ within a radius of 1.78 ± 0.03 h⁻¹ Mpc of its centre. We show that our predictions are rigorous across multiple training datasets and statistically consistent with historical estimates of Coma's mass. This measurement reinforces our understanding of the dynamical state of the Coma cluster and advances rigorous analyses and verification methods for empirical applications of machine learning in astronomy.