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 is motivated by the unprecedented survey capabilities of eROSITA onboard SRG, providing light curves for many thousand sources in its final-depth equatorial deep field survey....

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Bibliographic Details
Published inarXiv.org
Main Authors Buchner, Johannes, Boller, Thomas, Bogensberger, David, Malyali, Adam, Nandra, Kirpal, Wilms, Joern, Dwelly, Tom, Liu, Teng
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 17.01.2022
Subjects
Amplitudes
Bayesian analysis
Deviation
Light curve
Physics - High Energy Astrophysical Phenomena
Physics - Instrumentation and Methods for Astrophysics
Reliability analysis
Simulation
Sky surveys (astronomy)
Statistics - Computation
Statistics - Methodology
Variability
Variance
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Summary:The reliability of detecting source variability in sparsely and irregularly sampled X-ray light curves is investigated. This is motivated by the unprecedented survey capabilities of eROSITA onboard SRG, providing light curves for many thousand sources in its final-depth equatorial deep field survey. Four methods for detecting variability are evaluated: excess variance, amplitude maximum deviations, Bayesian blocks and a new Bayesian formulation of the excess variance. We judge the false detection rate of variability based on simulated Poisson light curves of constant sources, and calibrate significance thresholds. Simulations with flares injected favour the amplitude maximum deviation as most sensitive at low false detections. Simulations with white and red stochastic source variability favour Bayesian methods. The results are applicable also for the million sources expected in eROSITA's all-sky survey.
ISSN:2331-8422
DOI:10.48550/arxiv.2106.14529