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arXiv · 2608.12261

The Delay Time Distribution of Quasi-Periodic Eruptions

Margaret Shepherd·K. Decker French·Jason T. Hinkle·Ferdinand·Samaresh Mondal·Yashasvi Moon·Margaret E. Verrico
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Abstract

Quasi-periodic eruptions (QPEs) are quasi-periodic X-ray bursts observed in the nucleus of a galaxy. Multiple pieces of observational evidence link QPEs to tidal disruption events (TDEs), which occur when stars are disrupted after approaching a supermassive black hole too closely. Post-starburst galaxies are overrepresented among the host galaxies of both TDEs and QPEs, though the mechanism causing this overrepresentation is unknown. While their physical origin is unclear, the delay time distribution (DTD) of QPEs, or rate of QPEs as a function of time since a burst of star formation, can constrain what mechanisms influence the QPE rate and possible QPE formation channels. We compile a catalog of 10 QPE host galaxies with optical spectra, model the stellar populations with Bagpipes, and retrieve the age of the most recent burst of star formation to construct the DTD of QPEs. We find that the QPE rate increases with post-burst age to reach a peak at ~1 Gyr relative to a control sample, similar to the observational TDE DTD, though we cannot rule out a flat distribution of burst ages relative to a control sample. However, the fraction of QPE host galaxies with high (>1%) burst mass fractions is larger than the fraction of galaxies with high burst mass fractions in either a sample of TDE host galaxies or a sample of control galaxies. If the preferred QPE formation channel requires extreme mass ratio inspirals (EMRIs), then such EMRIs may be more readily produced by large, ~1-Gyr-old bursts of star formation.

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Margaret Shepherd, K. Decker French, Jason T. Hinkle, Ferdinand, Samaresh Mondal, Yashasvi Moon, Margaret E. Verrico. 2026-08-12. The Delay Time Distribution of Quasi-Periodic Eruptions. https://doi.org/10.3847/2041-8213%2Fae9c30

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