Cristina Mondino (Perimeter Institute)

10:00am Wednesday March 15, 2023

Dark photon superradiance: Electrodynamics and multimessenger signals

Black hole superradiance is a unique mechanism that allows a large cloud of ultralight bosons to grow around spinning black holes, requiring only gravitational interactions. I will focus on superradiance of vector fields around stellar mass black holes and consider a dark photon that kinetically mixes with the Standard Model photon. The dark photon superradiance cloud sources a strong rotating electromagnetic field around the black hole and initiates a transient phase of electron-positron pair production that populates a plasma inside the cloud. I will discuss the electrodynamics of the system, which shares qualitative features with a neutron star pulsar magnetosphere, and identify the main sources of electromagnetic emissions. The result is a new type of very luminous object, comparable to the brightest X-ray sources on the sky, with several unique features that can be looked for with existing and future telescopes. Observational strategies will be presented and include electromagnetic follow-ups of compact binary mergers and gravitational wave follow-ups of anomalous pulsars.