Detectable Signatures of Star Formation Stochasticity in Galaxy Spectra

Galaxy formation and evolution involves a variety of effectively stochastic processes operating over a range of timescales. We model variability in galaxy star formation histories (SFHs) using physically motivated log-Gaussian processes that incorporate variability due to stochastic gas inflows, baryon cycling and GMC creation and destruction. Using stellar population synthesis models, we explore how changes in model stochasticity can affect spectral signatures across galaxy populations with properties similar to the Milky Way and present-day dwarfs as well as at higher redshifts. We find that perturbing the stochasticity model by changing the amount of stochasticity or the effective timescales associated with the physical processes leaves unique spectral signatures across idealised and more realistic galaxy populations. Through distributions of spectral features, these provide testable predictions with larger sample sizes of galaxy populations from present and upcoming surveys with JWST & NGRST.