Beijing Institute of Mathematical Sciences and Applications

Jahed Abedi , Dey Dipanjan , Puskar Mondal , Alejandro Torres-Orjuela

Pau Amaro Seoane

Wednesday, March 25, 2026 2:30 PM - 3:30 PM

A3-2-301

Zoom 928 682 9093 (BIMSA)

The Galactic Centre contains populations of stellar-mass and substellar-mass compact objects orbiting the central black hole, classified as early extreme-mass ratio inspirals (E-EMRIs) and extremely large mass ratio inspirals (XMRIs). These systems constitute asymmetric binaries, characterized by mass ratios exceeding 10,0000 to 1. This mass differential causes the secondary body to approximate a test particle, completing tens of thousands or millions of orbital cycles prior to coalescence. This high cycle count delineates the spacetime geometry and multipolar structure of the central black hole with greater resolution than comparable-mass supermassive black hole binaries, which undergo rapid coalescence and exhibit fewer in-band cycles. The prolonged orbital data can in principle also facilitate topological analysis. By applying the Gauss-Bonnet theorem, the accumulated orbital precession parameters relate the integrated curvature of the spacetime to its topological invariants. The continuous gravitational wave emission from these populations generates a non-Gaussian, non-stationary composite signal within the frequency band of the Laser Interferometer Space Antenna. This aggregated signal comprises an incoherent superposition of individual waveforms from eccentric and circular orbits, which superimposes upon the spectral signatures of other target sources, including binaries of supermassive black holes and verification binaries. Spectral analysis indicates that sources with minimal frequency drift constitute an unresolved stochastic background, while systems with measurable frequency evolution produce distinct spectral components. Extracting targeted signals from this composite data requires time-frequency domain modeling and non-Poissonian statistical subtraction protocols.

I am working at the Institute for Multidisciplinary Mathematics of the Universitat Politècnica de València, I am also affiliated at the Max Planck Institute for Extraterrestrial Physics and at the group of Nobel laureate Reinhard Genzel. My background is in theoretical physics in Spain and I did my PhD on astrophysics at the University of Heidelberg. Since 2004 I have been working on gravitational waves, mostly from the point of view of source formation and evolution. I like to talk to people outside my research field, so I have been gradually expanding my interests: from accretion discs to tidal disruptions, stellar collisions, and supermassive black hole seed formation. However, lately my strongest interest lies in the connection between gravitational wave astrophysics with fundamental physics and spacetime geometry around supermassive black holes.