| Name: Banibrata Sarkar |
| Affiliation: Jadavpur University |
| Conference ID: ASI2026_100 |
| Title: Accretion Disk Signatures in Higher-Order Vacuum Gravitational Waves |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Banibrata Sarkar(Jadavpur University, Kolkata-700032, India), Soumen Mondal(Jadavpur University, Kolkata-700032, India), Prasad Basu(Cotton University, Assam-781001, India) |
| Abstract: Extreme mass-ratio inspirals (EMRIs) are expected to be one of the most prominent sources of gravitational waves for future space-based detectors like LISA and Taiji. However, most waveform models assume vacuum dynamics, while realistic EMRIs are likely to inhabit environments containing accretion disks, dark matter halos, and other material components.
Previous studies have shown that accretion disk effects are generally weaker than the leading-order vacuum gravitational-wave contributions, yet can still produce measurable imprints on the waveform. In this work, we systematically compare the impact of accretion disk–induced modifications with higher-order corrections to vacuum gravitational-wave fluxes. We construct a flux-modulated inspiral model in which additional disk-sourced angular momentum and energy fluxes are incorporated into the orbital evolution.
Using this framework, we compute gravitational-wave phase shifts relative to the vacuum case and assess their detectability with LISA. We further investigate how the accumulated dephasing depends on key accretion disk parameters. In addition, we perform a full Bayesian parameter estimation analysis to quantify the biases that arise when environmental effects are neglected in waveform modelling.
Our results show that disk-induced phase dephasings can accumulate to several radians over a typical LISA observation window, exceeding the threshold for detectability and leading to significant parameter biases if ignored. Accounting for these contributions will be essential for avoiding biases in black hole parameter inference and may even enable probing the properties of accretion disks through gravitational waves coupled with the electromagnetic observations, hence providing a path towards Multi-Messenger Astronomy.
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