Detectability of Massive Boson Stars using Gravitational Waves from Fundamental Oscillations

TL;DR

This paper develops analytical models for gravitational wave signals from massive Boson stars' fundamental oscillations, enabling their detection and dark matter property inference across various detectors and distances.

Contribution

It provides analytical fits for scaling relations and universal relations of Boson star oscillations, facilitating future gravitational wave studies without extensive numerical calculations.

Findings

Current detectors can detect Boson star $f$-modes up to 1 Mpc.

Future detectors like Cosmic Explorer and Einstein Telescope can reach 30 Mpc.

LISA could detect signals up to 300 Mpc in optimal scenarios.

Abstract

Boson Stars are macroscopic self-gravitating configurations made of complex scalar fields. These exotic compact objects would manifest as dark Boson stars and, in the absence of electromagnetic signatures, could mimic properties of compact stars in the gravitational wave spectrum. In a recent study, using the simplest potential for massive Boson stars, we demonstrated that fundamental non-radial oscillations ($f$-modes) obey scaling relations that allow them to be distinguished from neutron stars and black holes. In this work, we provide analytical fits for these scaling relations, valid for the dark matter parameter space compatible with current astrophysical and cosmological data, that can be directly incorporated into future studies of massive Boson stars in the strong coupling regime, avoiding the need for numerical calculations. We also provide analytical fits for empirical and universal relations for gravitational wave asteroseismology, which can be used to infer microscopic dark matter properties following a successful detection. Further, we investigate the possibility of detection of $f$-modes and the dark matter parameter space that can be probed with current and future gravitational wave detectors across multiple frequency bands. Assuming a burst gravitational wave model and demanding a signal-to-noise ratio of 5, we show that the current and future detectors can, in principle, probe Boson star $f$-modes up to cosmological distances: 1 Mpc with aLIGO, 30 Mpc with Cosmic Explorer and Einstein Telescope, and in the best case scenario, about 300 Mpc with LISA.