TY - JOUR

T1 - Astrophysical signatures of boson stars

T2 - Quasinormal modes and inspiral resonances

AU - Macedo, Caio F. B.

AU - Pani, Paolo

AU - Cardoso, Vitor

AU - Crispino, Luis C. B.

PY - 2013/9/23

Y1 - 2013/9/23

N2 - Compact bosonic field configurations, or boson stars, are promising dark matter candidates which have been invoked as an alternative description for the supermassive compact objects in active galactic nuclei. Boson stars can be comparable in size and mass to supermassive objects, and they might be hard to distinguish by electromagnetic observations. However, boson stars do not possess an event horizon, and their global spacetime structure is different from that of a black hole. This leaves a characteristic imprint in the gravitational-wave emission, which can be used as a discriminant between black holes and other horizonless compact objects. Here we perform a detailed study of boson stars and their gravitational-wave signatures in a fully relativistic setting, a study which was lacking in the existing literature in many respects. We construct several fully relativistic boson star configurations, and we analyze their geodesic structure and free oscillation spectra, or quasinormal modes. We explore the gravitational and scalar response of boson star spacetimes to an inspiraling stellar-mass object and compare it to its black hole counterpart. We find that a generic signature of compact boson stars is the resonant-mode excitation by a small compact object on stable quasicircular geodesic motion.

AB - Compact bosonic field configurations, or boson stars, are promising dark matter candidates which have been invoked as an alternative description for the supermassive compact objects in active galactic nuclei. Boson stars can be comparable in size and mass to supermassive objects, and they might be hard to distinguish by electromagnetic observations. However, boson stars do not possess an event horizon, and their global spacetime structure is different from that of a black hole. This leaves a characteristic imprint in the gravitational-wave emission, which can be used as a discriminant between black holes and other horizonless compact objects. Here we perform a detailed study of boson stars and their gravitational-wave signatures in a fully relativistic setting, a study which was lacking in the existing literature in many respects. We construct several fully relativistic boson star configurations, and we analyze their geodesic structure and free oscillation spectra, or quasinormal modes. We explore the gravitational and scalar response of boson star spacetimes to an inspiraling stellar-mass object and compare it to its black hole counterpart. We find that a generic signature of compact boson stars is the resonant-mode excitation by a small compact object on stable quasicircular geodesic motion.

KW - NONRADIAL OSCILLATIONS

KW - ACCRETION DISC

KW - STELLAR MODELS

KW - STABILITY

KW - EQUATION

KW - PULSATION

KW - RADIATION

U2 - 10.1103/PhysRevD.88.064046

DO - 10.1103/PhysRevD.88.064046

M3 - Journal article

VL - 88

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 6

M1 - 064046

ER -