Variational inference results for the core of Perseus as seen by Hitomi. (a) ELBO metric during variational distribution optimisation. (b) Redshift, bulk motion (v_bulk), and velocity dispersion (σ_v) posterior distributions obtained for the central regions of the Perseus cluster as seen by Hitomi/SXS, superimposed on the prior distribution for the redshift and the previous results from (Hitomi Collaboration 2016) in the central region. (c) Count spectra of the observations used in this spectral fit, superimposed on the folded model for each observation, and the corresponding residuals in σ.