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arXiv · 2602.03932

Discovery of crested quasi-periodic eruptions following the most luminous SRG/eROSITA tidal disruption event

Pietro Baldini·Arne Rau·Andrea Merloni·Benny Trakhtenbrot·Riccardo Arcodia·Margherita Giustini·Giovanni Miniutti·Seán J. Brennan·Michael Freyberg·Paula Sánchez-Sáez·Iuliia Grotova·Zhu Liu·Tianying Lian·Kirpal Nandra
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Abstract

We report the discovery of complex flaring activity from the galactic nucleus hosting the five-year-old tidal disruption event eRASSt J234402.9-352640 (J2344). With Einstein Probe and XMM-Newton observations, we detected highly structured soft X-ray variability. Through temporal decomposition of the XMM-Newton light curve and time-resolved spectral analysis, we identified broad, thermal flares recurring every $\sim$12 hours and lasting $\sim$2 hours, consistent with quasi-periodic eruptions (QPEs). Remarkably, these QPEs are accompanied by an unprecedented crest of hotter, shorter flares, each lasting between 5 and 30 minutes. These flares are predominantly found in the rising phases of the QPEs, although they also appear throughout the quiescence. These findings establish J2344 as a new member of the QPE emitter population and uncover a previously unobserved phenomenology that challenges current models of QPEs. In this letter, we present the phenomenological properties of this unique source and discuss possible interpretations within the framework of extreme-mass-ratio inspirals.

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Pietro Baldini, Arne Rau, Andrea Merloni, Benny Trakhtenbrot, Riccardo Arcodia, Margherita Giustini, Giovanni Miniutti, Seán J. Brennan, Michael Freyberg, Paula Sánchez-Sáez, Iuliia Grotova, Zhu Liu, Tianying Lian, Kirpal Nandra. 2026-02-03. Discovery of crested quasi-periodic eruptions following the most luminous SRG/eROSITA tidal disruption event. https://doi.org/10.1051/0004-6361%2F202558241

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