TripleGW: Comprehensive gravitational waveforms in hierarchical triples for LISA

Objective

This year, the LIGO-Virgo-KAGRA (LVK) collaboration announced detections of unusually massive and rapidly spinning binary black holes (BH) are difficult to reconcile with isolated stellar evolution, pointing instead to dynamical assembly and repeated mergers in galactic nuclei (GN). LISA, launching in the coming decade, will directly probe such environments through long-baseline phase and amplitude modulations—including line-of-sight acceleration and Doppler shifts and de Sitter/Lense–Thirring precession—thereby revealing the influence of a nearby supermassive BH. Existing studies largely assume circular, Newtonian orbits and non-spinning GN, leaving the relativistic, eccentric, and inclined regime near spinning GN essentially unexplored. The TripleGW project aims at filling this gap by developing new techniques for the rich phenomenology that GN can modify the binary BH waveforms. As a Marie Curie Fellow at the NBIA, I will develop theoretical techniques for eccentric, relativistic trajectories near spinning GN and novel techniques for orbital precession effects. I will release these advances as a rigorously validated, open-source Python package for LISA Working Groups and Open Data Challenges. Using these tools, I will perform end-to-end parameter-estimation and population studies to (i) detect and characterize GN environmental effects, and (ii) measure GN properties directly from gravitational wave data. The results will establish GN as a demonstrable formation channel for binary BH and deliver the first gravitational wave map of dynamical conditions in GN, precisely timed with LVK upgrades, third-generation ground-based detectors, and LISA's launch.