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Public Seminar of RPg Student:
Gravitational-Wave Signatures from Quasi-Periodic Eruptions

Speaker Mr. Leif LUI
Affiliation The University of Hong Kong
Date June 18, 2024 (Tuesday)
Time 4:00 p.m.
Venue Room 522, 5/F, Chong Yuet Ming Physics Building, The University of Hong Kong

Abstract

Quasi-periodic eruptions (QPEs) have evaded physicists and astronomers for the past couple of years, as we have detected their ultraluminous X-ray signatures from detectors like Chandra and XMM-Newton, but the mechanism that powers them remains a mystery. Given the elusive physical origin of QPEs, many theoretical models attempt to explain their electromagnetic (EM) signatures, with the most widely accepted being the extreme-mass-ratio-inspiral (EMRI) secondary disk collision model. In this seminar, we provide a theoretical framework to predict the gravitational-wave (GW) signatures from the collision of stellar-mass black holes (BH)/stars with an accretion disk from a supermassive black hole (SMBH) from black hole perturbation theory (BHPT). We first perform geodesic ray tracing (GRT) to reproduce the EM signatures seen by observations like GSN069. Subsequently, we compute the GW strain for quasi-elliptical EMRI orbits using the Teukolsky equation coupled to an energy-momentum tensor that mimics QPEs and the FastEMRIWaveform (FEW) software package. We plan to extend our analyses to generic Kerr geodesics and perform some Markov-Chain-Monte-Carlo (MCMC) simulations to predict the GW signatures for current QPEs. Assuming the EMRI secondary disk collision model is valid, the objective of this research is to provide novel predictions of the GW signatures of QPEs based on this model, and hopefully, these signatures can be detected by future space-based detectors like LISA, TianQin, or µ-Hz.

 

Anyone interested is welcome to attend.