March 4, 2026

Two-body relaxation in the EMRI-TDE disk model for Quasi Periodic Eruptions

Chiara Maria Allievi, Luca Broggi, Alberto Sesana, and Matteo Bonetti Quasi Periodic Eruptions (QPEs) are luminous bursts of soft X-rays recently discovered in galactic nuclei. They repeat on timescales of hours to weeks, superimposed to an otherwise stable quiescent X-ray level, consistent with emission from a radiatively efficient accretion flow around relatively low-mass massive black holes (MBHs). Although their physical origin is still debated, their quasi- periodicity naturally arises within the ’impact model’, in which the X-ray bursts are generated by the interaction between a stellar black hole (sBH) or a star in a close orbit around the central MBH and the accretion disk formed by a tidal disruption event (TDE).

September 3, 2025

Eccentricity distribution of extreme mass ratio inspirals

D. Mancieri, L. Broggi, M. Vinciguerra, A. Sesana, and M. Bonetti We present realistic eccentricity distributions for extreme mass ratio inspirals (EMRIs) forming via the two-body relaxation channel in nuclear star clusters, tracking their evolution up to the final plunge onto the central Schwarzschild massive black hole (MBH). We find that EMRIs can retain significant eccentricities at plunge, with a distribution peaking at \(e_\mathrm{pl}≈0.2\), and a considerable fraction reaching much higher values.

May 29, 2025

Updated predictions for gravitational wave emission from TDEs for next generation observatories

M. Toscani, L. Broggi, A. Sesana, and E. M. Rossi In this paper, we investigate the gravitational wave (GW) emission from stars tidally disrupted by black holes (TDEs), using a semi- analytical approach. Contrary to previous works where this signal is modeled as a monochromatic burst, we here take into account all its harmonic components. On top of this, we also extend the analysis to a population of repeated-partial TDEs, where the star undergoes multiple passages around the black hole before complete disruption.