Seeing Unseen Gravitational Wave Inspirals at the Galactic Center
Abstract
The Galactic Center is expected to host a population of extremely large mass-ratio inspirals (X-MRIs) migrating toward the supermassive black hole. We propose an observational approach utilizing the secular gravitational torque exerted by X-MRIs on the highly eccentric S-star S301. This approach is intrinsically limited by the stochastic nature of the surrounding stellar-mass black hole cusp. As S301 propagates through this granular medium, it experiences discrete gravitational encounters. Standard orbital fitting procedures inherently assume a smooth background potential; applying them to stochastic trajectories averages these discrete velocity discontinuities into a continuous secular drift. This introduces a systematic bias that mimics the X-MRI precession signal, invalidating traditional mass estimation techniques. To resolve this degeneracy, we implement a methodology based on the Wavelet Transform Modulus Maxima method to characterize the local Hölder regularity of the orbital motion. This model isolates the singular discontinuities induced by stellar-mass black hole encounters from the continuous torque of the X-MRI distribution, allowing for detection even when instantaneous accelerations are below the instrumental noise threshold. We demonstrate analytically that S301 is highly sensitive to the interior X-MRI population while remaining dynamically decoupled from the secular influence of the exterior cusp. Combining precision astrometry and radial velocity projections, we establish that a minimal population of two X-MRIs is detectable within a five to nine-year timeframe, allowing us to constrain the presence of an unseen orbiter population prior to the launch of space-based gravitational wave detectors.
Related
- Seeing in the Dark: Gravitational Waves from Resonant Production of Dark Photon Dark Matter
- A compact time-domain reduced order quadrature for gravitational wave inspirals with non-stationary noise
- Extreme Mass Ratio Inspirals in Light of Quasi-periodic Eruptions: Milli-Hertz Gravitational Wave Background
- A Multipole Technique for the Simulation and Analysis of Gravitational Waveforms from Extreme Mass Ratio Inspirals
- Associating binary black holes with galactic centres using lensed gravitational waves
BibTeX
@misc{seoane2026seeing,
title = {{Seeing Unseen Gravitational Wave Inspirals at the Galactic Center}},
author = {Pau Amaro Seoane and Qimin Song and Shao-Dong Zhao and Kostas Tzanavaris and Reinhard Genzel and Frank Eisenhauer and Thomas Ott and Stefan Gillessen and Guillaume Bourdarot and Diogo C. Ribeiro and Matteo Sadun Bordoni and Simran Joharle and Felix Mang and Andreas Burkert and Jorge Cuadra and Diego Calderón and Re'em Sari},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.37757},
eprint = {2610.37757},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.37757},
}
RIS
TY - UNPB
TI - Seeing Unseen Gravitational Wave Inspirals at the Galactic Center
AU - Pau Amaro Seoane
AU - Qimin Song
AU - Shao-Dong Zhao
AU - Kostas Tzanavaris
AU - Reinhard Genzel
AU - Frank Eisenhauer
AU - Thomas Ott
AU - Stefan Gillessen
AU - Guillaume Bourdarot
AU - Diogo C. Ribeiro
AU - Matteo Sadun Bordoni
AU - Simran Joharle
AU - Felix Mang
AU - Andreas Burkert
AU - Jorge Cuadra
AU - Diego Calderón
AU - Re'em Sari
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.37757
UR - https://arxiv.org/abs/2610.37757
AB - The Galactic Center is expected to host a population of extremely large mass-ratio inspirals (X-MRIs) migrating toward the supermassive black hole. We propose an observational approach utilizing the secular gravitational torque exerted by X-MRIs on the highly eccentric S-star S301. This approach is intrinsically limited by the stochastic nature of the surrounding stellar-mass black hole cusp. As S301 propagates through this granular medium, it experiences discrete gravitational encounters. Standard orbital fitting procedures inherently assume a smooth background potential; applying them to stochastic trajectories averages these discrete velocity discontinuities into a continuous secular drift. This introduces a systematic bias that mimics the X-MRI precession signal, invalidating traditional mass estimation techniques. To resolve this degeneracy, we implement a methodology based on the Wavelet Transform Modulus Maxima method to characterize the local Hölder regularity of the orbital motion. This model isolates the singular discontinuities induced by stellar-mass black hole encounters from the continuous torque of the X-MRI distribution, allowing for detection even when instantaneous accelerations are below the instrumental noise threshold. We demonstrate analytically that S301 is highly sensitive to the interior X-MRI population while remaining dynamically decoupled from the secular influence of the exterior cusp. Combining precision astrometry and radial velocity projections, we establish that a minimal population of two X-MRIs is detectable within a five to nine-year timeframe, allowing us to constrain the presence of an unseen orbiter population prior to the launch of space-based gravitational wave detectors.
ER -