Effect of accretion on scalar superradiant instability

TL;DR

This paper investigates how accretion influences scalar superradiant instabilities around black holes, revealing that accretion enhances gravitational wave emission and alters the GW signal characteristics.

Contribution

It provides analytical approximations for the evolution of superradiant systems with accretion, considering multiple modes, and explores their gravitational wave signatures.

Findings

Accretion significantly boosts GW emission.

Accretion shortens the GW signal duration.

GW beat signatures are notably affected.

Abstract

Superradiance can lead to the formation of a black hole (BH) condensate system. We thoroughly investigate the accretion effect on the evolution of this system, and the gravitational wave signals it emits in the presence of multiple superradiance modes. Assuming the multiplication of the BH mass and scalar mass as a small number, we obtain the analytical approximations of all important quantities, which can be directly applied to phenomenological studies. In addition, we confirm that accretion could significantly enhance the gravitational wave (GW) emission and reduce its duration, and show that the GW beat signature is similarly modified.