088188

In performing multiple all-sky X-ray surveys and monitoring several hundredthousand AGN every six months eROSITA has the capability to identify exceptionalAGN with a periodic X-ray flux signal. These objects are interpreted as closesupermassive black hole binary (SMBHB) candidates. Additional Swift data betweenthe half-a-year eROSITA data will be used first to confirm i) the periodicsignal and ii) the accurate period. Only in a such case will we initiate ourXMM-Newton pilot study program requesting one ToO observation of 120 ks for thebest eROSITA/Swift-selected periodic AGN. The detection of a double-peaked FeK$alpha$ emission will establish the SMBHB nature of the object. Due to theeROSITA observing pattern we can identify the closest-distance pairs ever discovered. [truncated! Please see actual data for full text]