Work

Dynamical Response of Viscous Objects to Gravitational Waves

Year: 2025

Type: article

Abstract: We study the dynamical response of viscous materials to gravitational waves, in the context of a fully relativistic theory of fluid dynamics. For the first time, we calculate oscillation modes and scattering properties of viscous stars. Viscous stars absorb high-frequency radiation, following a dispersion relation introduced by Press. In the extremely large viscosity regime, stars would become reflectors of waves, but this regime appears to be forbidden by causality bounds. In the context of black hole mimickers, we show how maximally viscous stars on the threshold of stability mimic the absorption of a black hole with the same mass. Our results suggest that rotating viscous stars will amplify incoming radiation.

Source: Physical Review Letters

DOI: 10.1103/smlr-v7b2

Authors: Valentin Boyanov, Vitor Cardoso, Kostas D. Kokkotas, Jaime Redondo-Yuste

Institutions: University of Lisbon, Instituto Superior Técnico, University of Copenhagen, University of Tübingen

Language: English

Topic: Pulsars and Gravitational Waves Research

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green