Abstract The Einstein Telescope (ET), the European project for a third-generation
gravitational-wave detector, has a reference configuration based on a triangular shape …

The birth of gravitational wave astronomy was triggered by the first detection of a signal
produced by the merger of two compact objects (also known as a compact binary …

Direct detection of gravitational waves has become a powerful new tool of multi-messenger
astrophysics. Apart from short-duration (transient) events, such as the inspirals and mergers …

Seven years after the first direct detection of gravitational waves, from the collision of two
black holes, the field of gravitational wave astronomy is firmly established. A first detection of …

We study the electrodynamics of a kinetically mixed dark photon cloud that forms through
superradiance around a spinning black hole, and design strategies to search for the …

Gravitational signatures of black hole superradiance are a unique probe of ultralight
particles that are weakly coupled to ordinary matter. The existence of an ultralight boson …

Sunlike stars can transmute into comparable mass black holes by steadily accumulating
heavy nonannihilating dark matter particles over the course of their lives. If such stars form in …

A massive spin-2 field can grow unstably around a black hole, giving rise to a potential
probe of the existence of such fields. In this work, we use time-domain evolutions to study …

Ultralight bosons are predicted in many extensions to the Standard Model and are popular
dark matter candidates. The black hole superradiance mechanism allows for these particles …

We study the impact of a binary companion on black hole superradiance at orbital
frequencies away from the resonance bands of the superradiant cloud. A superradiant state …