Evolution strategies applied to the problem of line profile decomposition in QSO spectra

This animation illustrates the decomposition of an ensemble of absorption lines into individual model components by means of an evolution strategy (ES) with covariance matrix adaption (CMA).

A simulated ensemble of eight absorption lines (red dots) is parametrised by three parameters per individual line and three parameters for the background continuum. The simulation resembles the intergalactic metal lines typically seen in lines of sight toward quasi-stellar objects (QSOs, here Ca II associated with the damped Lyman-alpha system toward HE 0515-4414).

Even after random initialisation, the CMA-ES eventually finds the optimal parametric decomposition of the spectrum (blue curve). In contrast, classic deterministic optimisation strategies require a very particular initialisation.