Abstract for Proposal 094351

Following up on a new serendipitous XMM-Newton TDE to find new QPEs

Quasi-Periodic Eruptions (QPEs) are the latest addition to the ever-growing family of extra-galactic transients. The first QPE source was discovered in 2019, with a current total of six sources. They appear to be linked to Tidal Disruption Events. Several models have been suggested, trying to account for the complex observed behaviour of these puzzling objects, but they all fall short in some aspects. Understanding these peculiar objects might help us constrain the physics of super-Eddington accretion, that happens in both TDEs and QPEs. To improve our knowledge of QPEs, a larger sample is required. We propose to follow up on a new X-ray serendipitous TDE, expected to be found by the newly deployed transient detection system STONKS, in order to assess the presence of QPEs in its decay.



Details on Observing Strategy and Trigger Criteria
We request an Anticipated ToO, joint with Swift. The first step will be triggered by the detection of a serendipitous X-ray TDE candidate in new XMM-Newton observations by the newly deployed STONKS transient detection system. We request 12 ks of Swift time, one 3 ks exposure every week over a month, starting the week after the alert is communicated by us. These will then lead to the trigger of a 100 ks XMM-Newton ToO if the source is showing a TDE-like decay (probability ~0.5), in the week after this second trigger is confirmed. A second observation of 100ks (probability ~0.5) is asked in the next visibility window of the source, typically a few months later. The total weighted observing time is 100ks XMM-Newton and 12ks Swift.