Abstract for Proposal 096065

SWIFT-XRT + XMM ToO follow-up of a new eROSITA QPE candidate

To date, only 8 bona-fide QPE sources are publicly known, of which only 4 were found through systematic X-ray searches allowing a calculation of their intrinsic volumetric rates. eROSITA archival data, despite the halt of operations, are still being screened to provide further candidates. We request followup on a further QPE candidate from eROSITA, which was recently re-prioritized based on its recent counterpart identification with a galaxy. Deep XMM data are needed for characterization of both eruptions and quiescence, although we conservatively request ~21ks of Swift-XRT time to trigger, in case eruptions are observed, a full XMM-Newton orbit with P_trigger~60%%.



Details on Observing Strategy and Trigger Criteria
We request the XRT monitoring to be taken any time before the start of the first XMM visibility window of the target. In case we see eruptions, we will trigger the XMM aToO. Urgency is medium-low, since QPEs would have been observed from 2020 until 2025 at that point.