TY - JOUR

T1 - Applications of the close-limit approximation

T2 - horizonless compact objects and scalar fields

AU - Annulli, Lorenzo

AU - Cardoso, Vitor

AU - Gualtieri, Leonardo

PY - 2022/5/19

Y1 - 2022/5/19

N2 - The ability to model the evolution of compact binaries from the inspiral to coalescence is central to gravitational wave astronomy. Current waveform catalogues are built from vacuum binary black hole models, by evolving Einstein equations numerically and complementing them with knowledge from slow-motion expansions. Much less is known about the coalescence process in the presence of matter, or in theories other than general relativity. Here, we explore the close limit approximation as a powerful tool to understand the coalescence process in general setups. In particular, we study the head-on collision of two equal-mass, compact but horizonless objects. Our results show the appearance of 'echoes' and indicate that a significant fraction of the merger energy goes into these late-time repetitions. We also apply the close limit approximation to investigate the effect of colliding black holes on surrounding scalar fields. Notably, our results indicate that observables obtained through perturbation theory may be extended to a significant segment of the merger phase, where in principle only a numerical approach is appropriate.

AB - The ability to model the evolution of compact binaries from the inspiral to coalescence is central to gravitational wave astronomy. Current waveform catalogues are built from vacuum binary black hole models, by evolving Einstein equations numerically and complementing them with knowledge from slow-motion expansions. Much less is known about the coalescence process in the presence of matter, or in theories other than general relativity. Here, we explore the close limit approximation as a powerful tool to understand the coalescence process in general setups. In particular, we study the head-on collision of two equal-mass, compact but horizonless objects. Our results show the appearance of 'echoes' and indicate that a significant fraction of the merger energy goes into these late-time repetitions. We also apply the close limit approximation to investigate the effect of colliding black holes on surrounding scalar fields. Notably, our results indicate that observables obtained through perturbation theory may be extended to a significant segment of the merger phase, where in principle only a numerical approach is appropriate.

KW - binary black holes

KW - extreme compact objects

KW - gravitational waves

KW - scalar fields

KW - COLLIDING BLACK-HOLES

KW - HEAD-ON COLLISIONS

KW - GRAVITATIONAL-RADIATION

KW - RELATIVISTIC STARS

KW - NORMAL-MODES

KW - INITIAL DATA

KW - BRANS-DICKE

KW - MASS

KW - SYSTEMS

KW - ENERGY

U2 - 10.1088/1361-6382/ac6410

DO - 10.1088/1361-6382/ac6410

M3 - Journal article

VL - 39

JO - Classical and Quantum Gravity

JF - Classical and Quantum Gravity

SN - 0264-9381

IS - 10

M1 - 105005

ER -