VizieR Online Data Catalog: Variable eROSITA X-ray sources in SEP (Bogensberger+, 2024)

The data were collected in the interval from December 13, 2019, until June 16, 2021. Some X-ray sources were only detected in eRASS3, and were not matched to optical counterparts, as that used the positions in the eRASS:2 catalogue. Coordinates are based on the J2000 epoch. An X-ray source was deemed to be variable if it exceeded the 3 sigma variability thresholds defined in the paper in either the AMPL_SIG or SCATT_LO variability quantifiers, in at least one of the three all-sky surveys. NEV_b adapts the normalised excess variance for the low count rate regime. It employs Bayesian statistics and remains accurate despite the varying fractional exposures of the eROSITA data. The normalised intrinsic variance changes stochastically over time, even if the process generating the variability is stationary, even without measurement uncertainties. Therefore, when comparing the NEV_b of different sources or the same source at different times, the intrinsic scatter in the normalised intrinsic variance should be included in the error. The total error in the measurement of NIV_{infinity} is found by adding the measurement error and the intrinsic scatter in quadrature. The periodograms of the brightest variable extragalactic sources were fitted with an aliased power-law model of the form P{prop.to}nu^-α. The periodogram index lists the best-fit values of α.

(1 data file).