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

TL;DR

This paper models gravitational wave emissions from tidal disruption events (TDEs), considering harmonic components and repeated disruptions, to predict detection prospects for future observatories like LISA and dHz missions.

Contribution

It introduces a comprehensive semi-analytical model for GW signals from TDEs, including harmonic analysis and repeated disruptions, extending previous monochromatic models.

Findings

Full disruptions are undetectable by LISA but targetable by dHz observatories.

Repeated disruptions produce GWs unlikely to be detected soon.

The results align with previous literature despite more conservative assumptions.

Abstract

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. For both populations, we estimate the rate of individual GW-detections considering future observatories like LISA and a potential deci-Hertz (dHz) mission, and derive the GW background from these sources. Our conclusions, even if more conservative, are consistent with previous results presented in literature. In fact, full disruptions of stars will not be seen by LISA but will be important targets for dHz observatories. In contrast, GWs from repeated disruptions will not be detectable in the near future.