Systematic evaluation of variability detection methods for eROSITA

The reliability of detecting source variability in sparsely and irregularly sampled X-ray light curves is investigated. This motivated by the unprecedented survey capabilities eROSITA on board Spektrum-Roentgen-Gamma observatory, providing for many thousand sources its final-depth equatorial deep-field survey. Four methods are evaluated: excess variance, amplitude maximum deviations, Bayesian blocks, a new formulation variance. We judge false-detection rate based simulated Poisson constant sources, calibrate significance thresholds. Simulations which flares injected favour deviation as most sensitive at low false detections. with white red stochastic methods. results applicable also million expected all-sky